We have assessed the different adhesive properties of some of the most common bacteria associated with periprosthetic joint infection on various types of ultra high molecular Weight Polyethylene (UHMWPE). Quantitative in vitro analysis of the adhesion of biofilm producing strains of Staphylococcus aureus and Escherichia coli to physically and chemically characterised standard UHMWPE (PE), vitamin E blended UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) was performed using a sonication protocol. A significant decreased bacterial adhesion was registered for both strains on VE-PE, in comparison with that observed on PE, within 48 hours of observation (S. aureus p = 0.024 and E. coli p = 0.008). Since Vitamin E reduces bacterial adhesive ability, VE-stabilised UHMWPE could be valuable in joint replacement by presenting excellent mechanical properties, while reducing bacterial adhesiveness. Cite this article: Bone Joint J 2014;96-B:497–501

Aim

Ciprofloxacin is recommended as anti-biofilm therapy for gram-negative periprosthetic joint infection. With ciprofloxacin monotherapy, resistance in gram-negative bacteria was observed. Therefore, we evaluated in vitro synergistic activity of fosfomycin, ciprofloxacin and gentamicin combinations against biofilms formed by E. coli and P. aeruginosa strains.

Aim. We aimed to assess the incidence and the outcome of Gram-negative prosthetic-joint infections (PJI) in 3 international tertiary hospital. Method. We included patients with Gram-negative PJI at Humanitas Clinical and Research Hospital (Milan, Italy), Centre Hospitalier Universitaire Vaudois (Lausanne, Switzerland) and Hospital Parc de Salut Mar (Barcelona, Spain) between 2014 and 2018 in a retrospective cohort. We described the treatment's success rate according to Gram-negative species and type of surgical procedure. Results. In the present cohort we have 780 PJI out of which 71 (9.1%) were caused by Gram-negative bacteria (polymicrobial infection 30%, Escherichia coli 25%, Pseudomonas aeruginosa 20%, Proteus spp. 4%, Klebsiella spp. 3%, Morganella morganii 3%, Enterobacter 3%, others 12%). Gram-negative PJI were more common in females (60%) than males (40%). Sixty percent had a hip infection, 40% a knee infection, the median age was 74 years and the median ASA score was 3. It was a chronic infection in 60% of the cases and an acute one in 40%. Two-step exchange was performed in 55%, débridement and retention (DAIR) in 30%, one-step exchange in 11% and implant removal without replacement in 4% of the patients. The overall treatment success rate was 89%. The success rate was better for two-step exchange (95%) compared to DAIR (81%) and one-step exchange (87%) (p=0.068). The median antibiotic duration was 68 days and ciprofloxacin was used in 70% of the cured patients versus in 88% of the failures (p=0.388). Infections caused by Escherichia coli were associated with a lower success rate (83%) especially compared to Pseudomonas aeruginosa (93%) and polymicrobial infections (90%) (p=0.358). Finally, the success rate was better in knee PJI compared to hip PJI (97% versus 83%, p=0.121) and in females compared to males (93% versus 82%, p=0.121). Conclusions. The treatment's success of Gram-negative PJI is comparable to reported rates for all bacteria. However, our results suggest that surgical management with two-step exchange might be useful in selected patients’ groups such as those with Escherichia coli PJI. Moreover, ciprofloxacin use seems not to improve cure rate

Aims. Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity. Methods. We retrospectively reviewed 32 patients (22 hips and 11 knees) who underwent single-stage revision combined with IA carbapenem infusion between November 2013 and March 2020. The IA and intravenous (IV) carbapenem infusions were administered for a single Gram-negative infection, and IV vancomycin combined with IA carbapenems and vancomycin was applied for polymicrobial infection including Gram-negative bacteria. The bacterial community distribution, drug sensitivity, infection control rate, functional recovery, and complications were evaluated. Reinfection or death caused by PJI was regarded as a treatment failure. Results. Gram-negative PJI was mainly caused by Escherichia coli (8/34), Enterobacter cloacae (7/34), and Klebsiella pneumoniae (5/34). Seven cases (7/32) involved polymicrobial PJIs. The resistance rates of penicillin, cephalosporin, quinolones, and sulfonamides were > 10%, and all penicillin and partial cephalosporins (first and second generation) were > 30%. Of 32 cases, treatment failed to eradicate infection in only three cases (9.4%), at a mean follow-up of 55.1 months (SD 25 to 90). The mean postoperative Harris Hip Score and Hospital for Special Surgery knee score at the most recent follow-up were 81 (62 to 91) and 79 (56 to 89), respectively. One patient developed a fistula, and another presented with a local rash on an infected joint. Conclusion. The use of IA carbapenem delivered alongside one-stage revision effectively controlled Gram-negative infection and obtained acceptable clinical outcomes with few complications. Notably, first- and second-generation cephalosporins and penicillin should be administrated with caution, due to a high incidence of resistance. Cite this article: Bone Joint J 2023;105-B(3):284–293

Aims. Trained immunity confers non-specific protection against various types of infectious diseases, including bone and joint infection. Platelets are active participants in the immune response to pathogens and foreign substances, but their role in trained immunity remains elusive. Methods. We first trained the innate immune system of C57BL/6 mice via intravenous injection of two toll-like receptor agonists (zymosan and lipopolysaccharide). Two, four, and eight weeks later, we isolated platelets from immunity-trained and control mice, and then assessed whether immunity training altered platelet releasate. To better understand the role of immunity-trained platelets in bone and joint infection development, we transfused platelets from immunity-trained mice into naïve mice, and then challenged the recipient mice with Staphylococcus aureus or Escherichia coli. Results. After immunity training, the levels of pro-inflammatory cytokines (tumour necrosis factor alpha (TNF-α), interleukin (IL)-17A) and chemokines (CCL5, CXCL4, CXCL5, CXCL7, CXCL12) increased significantly in platelet releasate, while the levels of anti-inflammatory cytokines (IL-4, IL-13) decreased. Other platelet-secreted factors (e.g. platelet-derived growth factor (PDGF)-AA, PDGF-AB, PDGF-BB, cathepsin D, serotonin, and histamine) were statistically indistinguishable between the two groups. Transfusion of platelets from trained mice into naïve mice reduced infection risk and bacterial burden after local or systemic challenge with either S. aureus or E. coli. Conclusion. Immunity training altered platelet releasate by increasing the levels of inflammatory cytokines/chemokines and decreasing the levels of anti-inflammatory cytokines. Transfusion of platelets from immunity-trained mice conferred protection against bone and joint infection, suggesting that alteration of platelet releasate might be an important mechanism underlying trained immunity and may have clinical implications. Cite this article: Bone Joint Res 2022;11(2):73–81

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.

Aims. Gram-negative infections are associated with comorbid patients, but outcomes are less well understood. This study reviewed diagnosis, management, and treatment for a cohort treated in a tertiary spinal centre. Methods. A retrospective review was performed of all gram-negative spinal infections (n = 32; median age 71 years; interquartile range 60 to 78), excluding surgical site infections, at a single centre between 2015 to 2020 with two- to six-year follow-up. Information regarding organism identification, antibiotic regime, and treatment outcomes (including clinical, radiological, and biochemical) were collected from clinical notes. Results. All patients had comorbidities and/or non-spinal procedures within the previous year. Most infections affected lumbar segments (20/32), with Escherichia coli the commonest organism (17/32). Causative organisms were identified by blood culture (23/32), biopsy/aspiration (7/32), or intraoperative samples (2/32). There were 56 different antibiotic regimes, with oral (PO) ciprofloxacin being the most prevalent (13/56; 17.6%). Multilevel, contiguous infections were common (8/32; 25%), usually resulting in bone destruction and collapse. Epidural collections were seen in 13/32 (40.6%). In total, five patients required surgery, three for neurological deterioration. Overall, 24 patients improved or recovered with a mean halving of CRP at 8.5 days (SD 6). At the time of review (two to six years post-diagnosis), 16 patients (50%) were deceased. Conclusion. This is the largest published cohort of gram-negative spinal infections. In older patients with comorbidities and/or previous interventions in the last year, a high level of suspicion must be given to gram-negative infection with blood cultures and biopsy essential. Early organism identification permits targeted treatment and good initial clinical outcomes; however, mortality is 50% in this cohort at a mean of 4.2 years (2 to 6) after diagnosis. Cite this article: Bone Jt Open 2024;5(5):435–443

Aims. In wound irrigation, 1 mM ethylenediaminetetraacetic acid (EDTA) is more efficacious than normal saline (NS) in removing bacteria from a contaminated wound. However, the optimal EDTA concentration remains unknown for different animal wound models. Methods. The cell toxicity of different concentrations of EDTA dissolved in NS (EDTA-NS) was assessed by Cell Counting Kit-8 (CCK-8). Various concentrations of EDTA-NS irrigation solution were compared in three female Sprague-Dawley rat models: 1) a skin defect; 2) a bone exposed; and 3) a wound with an intra-articular implant. All three models were contaminated with Staphylococcus aureus or Escherichia coli. EDTA was dissolved at a concentration of 0 (as control), 0.1, 0.5, 1, 2, 5, 10, 50, and 100 mM in sterile NS. Samples were collected from the wounds and cultured. The bacterial culture-positive rate (colony formation) and infection rate (pus formation) of each treatment group were compared after irrigation and debridement. Results. Cell viability intervened below 10 mM concentrations of EDTA-NS showed no cytotoxicity. Concentrations of 1, 2, and 5 mM EDTA-NS had lower rates of infection and positive cultures for S. aureus and E. coli compared with other concentrations in the skin defect model. For the bone exposed model, 0.5, 1, and 2 mM EDTA-NS had lower rates of infection and positive cultures. For intra-articular implant models 10 and 50 mM, EDTA-NS had the lowest rates of infection and positive cultures. Conclusion. The concentrations of EDTA-NS below 10 mM are safe for irrigation. The optimal concentration of EDTA-NS varies by type of wound after experimental inoculation of three types of wound. Cite this article: Bone Joint Res 2021;10(1):68–76

Objectives. Irrigation is the cornerstone of treating skeletal infection by eliminating pathogens in wounds. A previous study shows that irrigation with normal saline (0.9%) and ethylenediaminetetraacetic acid (EDTA) could improve the removal of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) compared with normal saline (NS) alone. However, it is still unclear whether EDTA solution is effective against infection with drug-resistant bacteria. Methods. We established three wound infection models (skin defect, bone-exposed, implant-exposed) by inoculating the wounds with a variety of representative drug-resistant bacteria including methicillin-resistant S. aureus (MRSA), extended spectrum beta-lactamase-producing E. coli (ESBL-EC), multidrug-resistant Pseudomonas aeruginosa (MRPA), vancomycin-resistant Enterococcus (VRE), multidrug-resistant Acinetobacter baumannii (MRAB), multidrug-resistant Enterobacter (MRE), and multidrug-resistant Proteus mirabilis (MRPM). Irrigation and debridement were repeated until the wound culture became negative. The operating times required to eliminate pathogens in wounds were compared through survival analysis. Results. Compared with other groups (NS, castile soap, benzalkonium chloride, and bacitracin), the EDTA group required fewer debridement and irrigation operations to achieve pathogen eradication in all three models of wound infection. Conclusion. Irrigation with EDTA solution was more effective than the other irrigation fluids used in the treatment of wound infections caused by drug-resistant pathogens. Cite this article: Z. Deng, F. Liu, C. Li. Therapeutic effect of ethylenediaminetetraacetic acid irrigation solution against wound infection with drug-resistant bacteria in a rat model: an animal study. Bone Joint Res 2019;8:189–198. DOI: 10.1302/2046-3758.85.BJR-2018-0280.R3

Introduction: Platelets play a central role in hemostasis and healing processes. Upon their activation, platelet alfa-granules release over 30 cytokines including platelet-derived growth factor (PDGF), transforming growth factor-alfa (TGF-alfa), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), epidermal growth factor (EGF) and also active substances like serotonin, catecholamines, von Willebrand factor, proaccelerin, osteonectin and antimicrobial proteins. By concentrating platelets, platelet-rich plasma (PRP) with higher levels of growth factors might be reached, which could stimulate the healing processes. The activator for PRP is a mixture of thrombin and calcium chloride. After connecting these substances platelet-rich gel (PRG) is formed. Aims: In present study, we investigated in vitro antimicrobial activity of PRG after antibiotic administration. Material and Methods: 30 minutes after iv Amoxillin/ clavulanic acid administration 54 ml of whole blood was collected from each of 10 donors. PRPs were prepared with using GPS system from Biomet. In vitro laboratory susceptibility to PRG was determined by the Kirby-Bauer disc diffusion method on Mueller-Hinton agar (Becton Dickinson). Baseline antimicrobial activity was assessed by measuring the zones of inhibition. Agar plates were coated with one of the following strain: Staphylococcus aureus ATCC 43300 (MRSA), Staphylococcus aureus ATCC 25923 (MSSA), Klebsiella pneumoniae ATCC 700603 (ESBL), Escherichia coli ATCC 35218 (ESBL), Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 27853. Results: We tested 10 samples of PRG. Zones of inhibition produced by PRG ranged between 6 – 23 mm in diameter. PRG inhibited the growth of Staphylococcus aureus. PG also was active against Escherichia coli, Enterococcus faecalis. No activity against Klebsiella pneumoniae and Pseudomonas aeruginosa was detected. Conclusions: Our previous study showed PRG no activity against Enterococcus faecalis without antibiotic administration. In this investigation we observed PRG strong activity against this bacteria after iv Amoxicillin-clavulanic acid administration. In infections during antibiotic treatment, PRG antimicrobial properties are enhanced by antibiotics that are concentrated in plasma

Aspiration arthrography using an iodinated contrast medium is a useful tool for the investigation of septic or aseptic loosening of arthroplasties and of septic arthritis. Previously, the contrast media have been thought to cause false negative results in cultures when present in aspirated samples of synovial fluid, probably because free iodine is bactericidal, but reports have been inconclusive. We examined the influence of the older, high osmolar contrast agents and the low osmolar media used currently on the growth of ten different micro-organisms capable of causing deep infection around a prosthesis. Five media were tested, using a disc diffusion technique and a time-killing curve method in which high and low inocula of micro-organisms were incubated in undiluted media. The only bactericidal effects were found with low inocula of Escherichia coli and Pseudomonas aeruginosa in ioxithalamate, one of the older ionic media. The low and iso-osmolar iodinated contrast media used currently do not impede culture. Future study must assess other causes of false negative cultures of synovial fluid and new developments in enhancing microbial recovery from aspirated samples

Hypochlorous acid (HOCl) is a potent anti-bacterial agent which could reduce periprosthetic joint infection. Early infection complications in joint replacements are often considered to be due to local contamination at the time of surgery and result in a significant socioeconomic cost. Current theatre cleaning procedures produce “clean” operating theatres which still contain bacteria (colony forming units, CFU). Reducing this bacterial load may reduce local contamination at the time of surgery. HOCl is produced naturally in the human neutrophil and has been implicated as the primary agent involved in bacterial killing during this process. In vitro research confirms its efficacy against essentially all clinically relevant bacteria. The recent advent of commercial production of HOCl, delivered as a fog, has resulted in extensive use in the food industry. Reported lack of corrosion and high anti-bacterial potency are seen as two key factors for the use of HOCl in the orthopaedic environment. Prior work by the authors comparing human cell toxicity of HOCl, chlorhexidine and iodine solutions shows favourable results. This study evaluates use of neutral HOCl applied as a dry room fog to decrease bacteria in the operating theatre environment. Using an animal operating theatre as the test site, bacterial swabs were taken from ten 100cm. 2. sample areas before standard cleaning with detergent, after standard cleaning, and again after 60 minutes exposure to HOCl fog. After standard cleaning, 6 of 10 sample sites recorded significant bacterial growth (>10 CFU/100cm. 2. ). After exposure to HOCl fog, growth in all 10 sites was below detection limits (<10 CFU/100cm. 2. ). This was repeated with specific exposure to Staphylococcus aureus and Escherichia coli. We can conclude that HOCl is effective when used as a fogging agent to reduce bacterial loading within an operating theatre environment and as such has significant potential to reduce intraoperative contamination and periprosthetic infection

Aim. Currently, gram-negative bacteria (GNB), including multidrug-resistant (MDR-GNB) pathogens, are gaining importance in the aetiology of prosthetic joint infection (PJI). To characterize the antimicrobial resistance patterns of Gram-negative bacteria (GNB) causing hip prosthetic joint infections in elderly patients treated at a Brazilian tertiary academic hospital. Method. This is a retrospective, cross-sectional study of patients over 60 years of age undergoing hip arthroplasty from 2018 to 2023 at a tertiary academic trauma, which were diagnosed with hip prosthetic joint infection. PJI diagnosed was based on EBJIS criteria, in which intraoperative tissue cultures identified the pathogens. Demographics, reason for arthroplasty, type of implant and susceptibility patterns using disk diffusion method were analysed. Results. Overall, among 17 elderly patients diagnosed with hip infected arthroplasty, 45 bacterial isolated were identified. Debridement, irrigation, antibiotic and implant retention (DAIR) procedures due to uncontrolled infection occurred in 47.0% (n=8/17), and five patients underwent more than two DAIR surgeries. Tissue cultures yielded eleven different bacterial species, with GNB accounted for 64.4% (n=29/45) of pathogens. Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, and Pseudomonas aeruginosa were identified in 34.5% (n=10/29), 17.25% (n=5/29), 13.8% (n=4/29), and 13.8% (n=4/29), respectively. In the resistance profile analysis, E. coli was most sensitive to antibiotics, whereas K. pneumoniae showed resistance rates higher than 70% for cephalosporins, carbapenems, and quinolones. All A. baumannii isolates were resistant to meropenem, and 80% of these isolates were resistant to amikacin. Conclusions. This study emphasizes the role of GNB in the microbiological profile of PJI among elderly patients at a tertiary hospital in a Brazilian centre. The present study portrays a worryingly higher rates of MDR-GNB, mainly to quinolones and cephalosporins resistance which have been the cornerstone of PJI antibiotic treatment. In addition, higher rates carbapenems and aminoglycosides resistance shows a threat to antibiotic treatment of PJI. More global studies need to be carried out to show a likely change in the microbial epidemiology of PJI

Aim. Prosthetic joint infections pose a major clinical challenge. Developing novel material surface technologies for orthopedic implants that prevent bacterial adhesion and biofilm formation is essential. Antimicrobial coatings applicable to articulating implant surfaces are limited, due to the articulation mechanics inducing wear, coating degradation, and toxic particle release. Noble metals are known for their antimicrobial activity and high mechanical strength and could be a viable coating alternative for orthopaedic implants [1]. In this study, the potential of thin platinum-based metal alloy coatings was developed, characterized, and tested on cytotoxicity and antibacterial properties. Method. Three platinum-based metal alloy coatings were sputter-coated on medical-grade polished titanium discs. The coatings were characterized using optical topography and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Ion release was measured using inductively coupled plasma optical emission spectrometry (ICP-OES). Cytotoxicity was tested according to ISO10993-5 using mouse fibroblasts (cell lines L929 and 3T3). Antibacterial surface activity, bacterial adhesion, bacterial proliferation, and biofilm formation were tested with gram-positive Staphylococcus aureus ATCC 25923 and gram-negative Escherichia coli ATCC 25922. Colony forming unit (CFU) counts, live-dead fluorescence staining, and SEM-EDS images were used to assess antibacterial activity. Results. Three different platinum-based metal alloys consisting of platinum-iridium, platinum-copper, and platinum-zirconium. The coatings were found 80 nm thick, smooth (roughness average < 60 nm), and non-toxic. The platinum-copper coating showed a CFU reduction larger than one logarithm in adherent bacteria compared to uncoated titanium. The other coatings showed a smaller reduction. This data was confirmed by SEM and live-dead fluorescence images, and accordingly, ICP-OES measurements showed low levels of metal ion release from the coatings. Conclusions. The platinum-copper coating showed low anti-adhesion properties, even with extremely low metal ions released. These platinum-based metal alloy coatings cannot be classified as antimicrobial yet. Further optimization of the coating composition to induce a higher ion release based on the galvanic principle is required and copper looks most promising as the antimicrobial compound of choice. Acknowledgments. This publication is supported by the DARTBAC project (with project number NWA.1292.19.354) of the research program NWA-ORC which is (partly) financed by the Dutch Research Council (NWO); and the AMBITION project (with project number NSP20–1-302), co-funded by the PPP Allowance made available by Health-Holland, Top Sector Life Sciences & Health to ReumaNederland

Aim. Antibacterial activity of coatings based on metal and metal oxide nanoparticles (NPs) often depends on materials and biotic targets resulting in a material-specific killing activity of selected Gram-positive and Gram-negative bacteria, including drug-resistant strains. In this perspective, the NPs loading amount, the relative elemental concentration inside the nanogranular building blocks and the deposition method are of paramount importance when the goal is to widen the antimicrobial spectrum, but at the same time to avoid high levels of metal content to limit undesired toxic effects. Aim of the present study was evaluation of the antimicrobial properties of two multielement nanogranular coatings composed of Titanium-Silver and Copper and of Magnesium-Silver and Copper. Method. Ti-Ag-Cu and Mg-Ag-Cu NPs were deposited on circular cover glasses (VWR) by Supersonic Cluster Beam Deposition. Biofilm-producer strains of Staphylococcus aureus (methicillin susceptible and resistant), Staphylococcus epidermidis (methicillin susceptible and resistant), Escherichia coli (fully susceptible and producer of extended spectrum beta lactamases), and Pseudomonas aeruginosa (susceptible and multidrug-resistant) were selected. The abilities of the selected strains to adhere, colonize and produce biofilm on the discs coated with Ti-Ag-Cu or Mg-Ag-Cu NPs were compared to uncoated circular cover glasses which were used as growth control. Cytotoxicity was also evaluated in order to assess the biocompatibility of the newly synthesized NPs. Results. In comparison to uncoated controls, both coatings showed significant anti-adhesive properties against S. aureus, S. epidermidis, and E. coli. Reduction in adhesion to Mg-Ag-Cu coated discs was observed also for P. aeruginosa isolates, although differences vs uncoated controls did not reach statistical significance. Biofilm formation was reduced on discs coated with Mg-Ag-Cu compared to Ti-Ag-Cu and, again, coatings had a milder effect on P. aeruginosa, probably due to its exceptional capability of attachment and matrix production. These results were confirmed by the evaluation of bacterial colonization on nanoparticles-coated discs by means of confocal laser scanning microscopy. A viability of 95.8% and 89.4% of cells cultured in the presence of Ti-Ag-Cu and Mg-Ag-Cu discs, respectively, when compared to negative controls was observed, thus excluding cytotoxic effects on eukaryotic cells. Conclusions. The newly synthesized Ti-Ag-Cu and Mg-Ag-Cu coatings are able to limit bacterial adhesion colonization and biofilm production, thus highlighting the safe use of multi-element families of NPs as new strategies against bacterial attachment to the surface of biomedical implants. However, further studies addressing activity against P. aeruginosa and including a wide number of isolates are warranted

Prosthetic joint infections represent complications connected to the implantation of biomedical devices. Bacterial biofilm is one of the main issues causing infections from contaminated orthopaedic prostheses. Biofilm is a structured community of microbial cells that are firmly attached to a surface and have unique metabolic and physiological attributes that induce improved resistance to environmental stresses including toxic compounds like antimicrobial molecules (e.g. antibiotics). Therefore, there is increasing need to develop methods/treatments exerting antibacterial activities not only against planktonic (suspended) cells but also against adherent cells of pathogenic microorganisms forming biofilms. In this context, metal-based coatings with antibacterial activities have been widely investigated and used in the clinical practice. However, traditional coatings exhibit some drawbacks related to the insufficient adhesion to the substrate, scarce uniformity and scarce control over the toxic metal release reducing the biofilm formation prevention efficacy. Additionally, standardized and systematic approaches to test antibacterial activity of newly developed coatings are still missing, while standard microbiological tests (e.g. soft-agar assays) are typically used that are limited in terms of simultaneous conditions that can be tested, potentially leading to scarce reproducibility and reliability of the results. In this work, we combined the Calgary Biofilm Device (CBD) as a device for high-throughput screening, together with a novel plasma-assisted technique named Ionized Jet Deposition (IJD), to generate and test new generation of nanostructured silver- and zinc-based films as coatings for biomedical devices with antibacterial and antibiofilm properties. During the experiments we tested both planktonic and biofilm growth of four bacterial strains, two gram-positive and two gram-negative bacterial strains, i.e. Staphylococcus aureus ATCC 6538P, Enterococcus faecalis DP1122 and Escherichia coli ATCC 8739 and Pseudomonas aeruginosa PAO1, respectively. The use of CBD that had the only wells covered with the metal coatings while the biofilm supports (pegs) were not sheltered allowed to selectively define the toxic effect of the metal release (from the coating) against biofilm development in addition to the toxic activity exerted by contact killing mechanism (on biofilms formed on the coating). The results indicated that the antibacterial and antibiofilm effects of the metal coatings was at least partly gram staining dependent. Indeed, Gram negative bacterial strains showed high sensitivity toward silver in both planktonic growth and biofilm formation, whereas zinc coatings provided a significant inhibitory activity against Gram positive bacterial strains. Furthermore, the coatings showed the maximal activity against biofilms directly forming on them, although, Zn coating showed a strong effect against biofilms of gram-positive bacteria also formed on uncoated pegs. We conclude that the metal-based coatings newly developed and screened in this work are efficient against bacterial growth and adherence opening possible future applications for orthopedic protheses manufacturing

Objective. To assess the beneficial use of polypropylene mesh impregnated with vancomycin in an experimental model open fractures Gustilo IIIa in rabbits. Material and Method. We worked with 15 New Zeland White rabbits. All of them were carried out under general anaesthetic, a 5-cm incision longitudinal was made at the back of the right thigh. The femur was aproached and a fracture was performed with a shear, giving rise to a multifragment fracture. The wound remained open for 6 hours with the bone exposed, in a non-surgical ambient. Subsequently underwent surgical cleaning of the open fractures in two stages. The fracture was stabilized with an intramedular pin. The animals were sorted in 3 different therapeutic groups:. Group 1: (5 rabbits) without other treatment. Group 2: (5 rabbits) a polypropylene mesh was placed around the fracture. Group 3: (5 rabbits) a polypropylene mesh with vancomycin was placed around the fracture. The wound was closed with nylon stiches. Three weeks postoperative, the animals were intervened surgically under general anesthesia, after aseptic cure and placement of surgical fields, femoral bone biopsies, soft tissue and mesh were taken. The rabbits were sacrified. The samples were sent to pathology and bacteriology labs. Results. The bacteria isolated were as follows: Escherichia coli, Pasteurella multocida, Staphylococcus spp., Clostridium spp. Mamheinia spp. The Clostridium spp. is a common contaminant in the exposed fractures present in the environment. The Pasteurella mustocida is a microorganism present in the oral cavity of rabbits, as well as Escherichia coli is a germ present in the animal's digestive tract. Mannheimia spp. It is a beta-hemolytic organism, found in the nasal flora of these animals and their pathological role is not elucidated. Staphylococcus spp. is a germ that is found in the normal flora of the animals skin. Group 1 showed a relative risk for an infection. For Group 2 the relative risk was substantially greater than 1.4, while in Group 3, the relative risk was 0.6, significantly lower than the previous two groups. The results have shown a beneficial effect of the use of impregnated polypropylene mesh with vancomycin in this animal group. Conclusion. The use of polypropylene meshes with vancomycin could be useful in the treatment of muscle and ligamentary deficits in patients with open fractures Gustillo IIIa

Objectives. There is increasing application of bone morphogenetic proteins (BMPs) owing to their role in promoting fracture healing and bone fusion. However, an optimal delivery system has yet to be identified. The aims of this study were to synthesise bioactive BMP-2, combine it with a novel α-tricalcium phosphate/poly(D,L-lactide-co-glycolide) (α-TCP/PLGA) nanocomposite and study its release from the composite. Methods. BMP-2 was synthesised using an Escherichia coli expression system and purified. In vitro bioactivity was confirmed using C2C12 cells and an alkaline phosphatase assay. The modified solution-evaporation method . was used to fabricate α-TCP/PLGA nanocomposite and this was characterised using X-ray diffraction and scanning electron microscopy. Functionalisation of α-TCP/PLGA nanocomposite by adsorption of BMP-2 was performed and release of BMP-2 was characterised using an enzyme-linked immunosorbent assay (ELISA). Results. Alkaline phosphatase activity of C2C12 cells was increased by the presence of all BMP-2/nanocomposite discs compared with the presence of a blank disc (p = 0.0022), and increased with increasing incubation concentrations of BMP-2, showing successful adsorption and bioactivity of BMP-2. A burst release profile was observed for BMP-2 from the nanocomposite. . Conclusions. Functionalisation of α-TCP/PLGA with BMP-2 produced osteoinduction and was dose-dependent. This material therefore has potential application as an osteoinductive agent in regenerative medicine

Aim. The efficacy of various irrigation solutions in removing microbial contamination of a surgical wound and reducing the rate of subsequent surgical site infection (SSI), has been demonstrated extensively. However, it is not known if irrigation solutions have any activity against established biofilm. This issue is pertinent as successful management of patients with periprosthetic joint infection (PJI) includes the ability to remove biofilm established on the surface of implants and necrotic tissues. The purpose of this study was to evaluate the efficacy of various irrigation solutions in eradicating established biofilm, as opposed to planktonic bacteria, in a validated in vitro model. Method. Established biofilms of Staphylococcus aureus and Escherichia coli were exposed to different irrigation solutions that included Polymyxin 500,000U/L plus bacitracin 50,000U/L, Vancomycin 1g/L, Gentamicin 80mg/L, Normal saline 0.9%, off-the-shelf Betadine 0.3%, Chlorhexidine 0.05%, Benzalkonium 1.3g/L, Sodium hypochlorite 0.125%, and Povidone-iodine 0.5%. Each experiment was conducted in a 96-well microtiter plate with a peg lid and standardized per the MBEC assay manufacturer's protocol. Following 2 minutes of solution exposure to the irrigation solution, residual biofilms were recovered by sonication. Outcome measures for antibiofilm efficacy were residual colony forming units (CFU) and optical density (690nm). Experiments were conducted in 24 replicates and the observations recorded by two blinded observers. Statistical analysis involved t-tests with Bonferonni adjustment. Results. Povidone-iodine 0.5%, Betadine 0.3%, Benzalkonium 1.3g/L, and Sodium hypochlorite 0.125% were significantly more efficacious against S.aureus biofilm versus all other solutions (p<0.001). Against E.coli biofilm, Povidone-iodine-0.5%, Benzalkonium-1.3g/L and Sodium hypochlorite-0.125% were also most effective compared to other irrigation solutions (p<0.001). Polymyxin-bacitracin, Gentamicin, Vancomycin, and Saline solutions had minimal activity against both E.coli and S.aureus biofilms (p<0.001). Similar trends were observed using both experimental endpoints (CFU and Turbidity) and both investigators (interrater reliability; r=0.99). Conclusion. This in vitro study observed that topical antibiotic solutions do not have any activity against established biofilms. Irrigations solutions containing adequate amount of povidone-iodine, betadine, sodium hypochlorite, and benzalkonium appear to have activity against established biofilm by gram positive and gram negative organisms. The use of these irrigation solutions may need to be considered in patients with established PJI

Platelet-rich plasma is a new inductive therapy which is being increasingly used for the treatment of the complications of bone healing, such as infection and nonunion. The activator for platelet-rich plasma is a mixture of thrombin and calcium chloride which produces a platelet-rich gel. We analysed the antibacterial effect of platelet-rich gel in vitro by using the platelet-rich plasma samples of 20 volunteers. In vitro laboratory susceptibility to platelet-rich gel was determined by the Kirby-Bauer disc-diffusion method. Baseline antimicrobial activity was assessed by measuring the zones of inhibition on agar plates coated with selected bacterial strains. Zones of inhibition produced by platelet-rich gel ranged between 6 mm and 24 mm (mean 9.83 mm) in diameter. Platelet-rich gel inhibited the growth of Staphylococcus aureus and was also active against Escherichia coli. There was no activity against Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa. Moreover, platelet-rich gel seemed to induce the in vitro growth of Ps. aeruginosa, suggesting that it may cause an exacerbation of infections with this organism. We believe that a combination of the inductive and antimicrobial properties of platelet-rich gel can improve the treatment of infected delayed healing and nonunion

We have investigated the contaminating bacteria in primary hip arthroplasty and their sensitivity to the prophylactic antibiotics currently in use. Impressions (627) of the gloved hands of the surgical team in 50 total hip arthroplasties were obtained on blood agar. The gloves were changed after draping, at intervals of 20 minutes thereafter, and before using cement. Changes were also undertaken whenever a visible puncture was detected. The culture plates were incubated at 37°C for 48 hours. Isolates were identified and tested for sensitivity to flucloxacillin, which is a recognised indicator of sensitivity to cefuroxime. They were also tested against other agents depending upon their appearance on Gram staining. We found contamination in 57 (9%) impressions and 106 bacterial isolates. Coagulase-negative staphylococci were seen most frequently (68.9%), but we also isolated Micrococcus (12.3%), diphtheroids (9.4%), Staphylococcus aureus (6.6%) and Escherichia coli (0.9%). Of the coagulase-negative staphylococci, only 52.1% were sensitive to flucloxacillin and therefore to cefuroxime. We believe that it is now appropriate to review the relevance of prophylaxis with cefuroxime and to consider the use of other agents

Aim. Bone and joint infections are frequent in African countries and their prevention and treatment remain a great challenge. This study aimed to determine the bacterial ecology and sensitivity of isolates to locally available antibiotics in orthopedic unit of a tertiary care hospital in Cameroun. Method. During a 12 months period, all the patients presenting with osteomyelitis or septic arthritis irrespective of the mechanism and the location were enrolled in this study. Intraoperative samples (biopsies) were taken and sent for microbiological analysis, and all strains isolated were tested for antibiotic sensitivity according to conventional methods. Results. on the 52 bacteriological analysis performed, 48 were positive. The most isolated germs were staphylococcus aureus (41.9 % of isolates), pseudomonas aeruginosa (14.5 %), Escherichia coli (14.5 %) and Klebsiella pneumonia (12.9 %). The antibiotic sensitivity pattern revealed worrying resistance rates for common and affordable antibiotics: ampicillin (94 %), amoxicillin + clavulanic acid (63.9 %), ceftazidim (65.5%), ticarcillin + clavulanate (57.4%), gentamycin (49 %), ciprofloxacin (40 %), cefuroxim (40 %), tobramycin (38.5 %). The strains of Staphylococcus aureus showed resistance to penicillin G (83%), oxacillin (25%), lincomycin (27%) and vancomycin (7%). The overall highest sensitivity rates were observed with amikacin (92 %) and imipenem (90.1%), which for many patients were the only effective locally available antibiotics. The daily cost of treatment with those two antibiotics is close to the guaranteed minimum wage in our country. Conclusions. The alarming rate of multidrug-resistant bacteria makes the long antibiotic treatment of bone infections unaffordable (in a context of lack of social insurance) for most of our patients. We advocate strong national policies for bacteriological surveillance and antibiotic misuse de-escalation to prevent antibiotic resistance

Antimicrobial resistance (AMR) is projected to result in 10 million deaths every year globally by 2050. Without urgent action, routine orthopaedic operations could become high risk and musculoskeletal infections incurable in a “post-antibiotic era.” However, current methods of studying AMR processes including bacterial biofilm formation are 2D in nature, and therefore unable to recapitulate the 3D processes within in vivo infection. Within this study, 3D printing was applied for the first time alongside a custom-developed bioink to bioprint 3D bacterial biofilm constructs from clinically relevant species including Staphylococcus aureus (MSSA), Methicillin-resistant staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa. Bacterial viability and biofilm formation in bioprinted constructs was excellent, with confocal laser scanning microscopy (CSLM) used to demonstrate biofilm production and maturation over 28 days. Bioprinted 3D MRSA and MSSA biofilm constructs had greater resistance to antimicrobials than corresponding two-dimensional (2D) cultures. Thicker 3D E.coli biofilms had greater resistance to tetracycline than thinner constructs over 7 days of treatment. Raman spectroscopy was also adapted in a novel approach to non-invasively diagnose 3D bioprinted biofilm constructs located within a joint replacement model. In conclusion, mature bacterial biofilm constructs were reproducibly 3D bioprinted for the first time using clinically relevant bacteria. This methodology allows the study of antimicrobial biofilm penetration in 3D, and potentially aids future antimicrobial research, replicating joint infection more closely than current 2D culture models. Furthermore, by deploying Raman spectroscopy in a novel fashion, it was possible to diagnose 3D bioprinted biofilm infections within a joint replacement model

Protocols for processing of tissue from arthroplasty infections vary and might affect the recovery of bacteria. We compared homogenization, bead beating and enzymatic disruption for recovery of live bacteria from tissue samples. Suspensions of Staphylococcus aureus and Escherichia coli were prepared as controls. Three samples were taken from each and the first was bead beaten, the second homogenized, and Proteinase K was added for 10 and 30 minutes to the third sample before culturing. In addition, artificially inoculated pork tissue and known infected human tissue samples were processed by either homogenization or bead beating prior to cultures and results were compared. Number of cycles of bead beating and homogenization and duration of Proteinase K treatment had significant effects. Bead beating for 2 and 4 cycles reduced the yield of S.aureus to 52% and 20% of control, and E.coli to 33% and 8%. Homogenization for 2 and 4 cycles reduced S.aureus to 86% and 65% of control, and E.coli to 90% and 87%. Proteinase K for 10 minutes and 30 minutes reduced the yield of S.aureus to 75% and 33% of control, and E.coli to 91% and 49% respectively. Inoculated Pork tissue showed a reduction in S.aureus recovery of 90% for bead beating compared to homogenization, and 80% in the case of E.coli. Bead beating of infected human tissue samples reduced the yield by 58% compared to homogenization. Bead-beating is a common recommended method of processing tissue from arthroplasty cases. However, even though it produces a homogeneous sample, it does so at the cost of significant loss of viable bacteria. Homogenization and 10 minutes of Proteinase K incubation are almost equivalent, but the homogenizer is preferred being more controllable and cheaper. This should help to define guidelines for diagnosing infections using tissue samples

Aim. Phage therapy has attracted attention as a promising alternative treatment option for biofilm infections. To establish a successful phage therapy, a comprehensive stock of different phages covering a broad bacterial spectrum is crucial. We screened human and environmental sources for presence of lytic phages against selected bacteria. Methods. Saliva collected from 10 volunteers and 500 ml of sewage water were screened for the presence of lytic phages active against 20 clinical strains of Staphylococcus aureus and 10 of Escherichia coli, both isolated from patients with prosthetic joint infection. Laboratory strains of methicillin-resistant S. aureus (MRSA)*1 and E. coli*2 were also tested. Screening was performed plaque-assay to detect phages for different strains. Isolated plaques were collected and phages were enriched to determine their activity against their bacterial host strains. The activity of bacteriophages against adherent E. coli and MRSA was evaluated by crystal violet, staining bacterial biofilms grown on glass beads. Results. Six bacteriophages specific for MRSA were isolated from saliva. Bacteriophages for E. coli strains were isolated from sewage water (n=3) and saliva (n=1). All bacteriophages tested against biofilms of their bacterial host showed a reduction of the total biomass (ranging from 19% to 84%). Conclusions. Both sewage and saliva samples provided bacteriophages specific against selected bacterial strains. 24h phage treatment of E. coli and S. aureus biofilms lead to a reduction but not to a complete eradication of biofilm

Aim. Prosthetic joint infections (PJI) due to Enterobacter cloacae are rare and often severe. The aim of this study is to describe cases with E. cloacae PJI. Method. We conducted a retrospective and a monocentric study in an orthopedic unit where complex bone and joint infections are managed. From 2012 to 2016, we included patients with PJI which perioperative samples were positive with E. cloacae. We collected background, clinical, biological and microbiological data of the current infection, surgical and medical treatment, and the outcome of these patients. Results. A total of twenty patients were included which 8 were male. Location was hip in 14 cases, knee in 5 cases and ankle in one case. The median time between arthroplasty and revision for infection was 3 years. Fourteen patients had at least two surgeries for previous PJI. The median time between the last surgery and the revision for E. cloacae infection was 31 days. Eleven patients were infected by extended-spectrum beta-lactamases (ESBL) strains. Most frequently, the antibiotics used were carbapenem in 9 cases, cefepim in 7 cases, a quinolone in 7 cases and fosfomycin in 4 cases. Infection was cured in 10 cases (50%) with a median time of follow-up of 24 months. Five patients had a recurrent infection, three due to Staphylococcus epidermidis, one to Staphylococcus epidermidis and Propionibacterium acnes and one to Escherichia coli. Four patients had a relapse of E. cloacae infection. One patient died from non-infectious cause (stroke). Conclusions. PJI infections due to E.cloacae usually occur early after the last prosthetic surgery, typically in patients with complex surgical history. A poor outcome, observed in nearly half of the patients could be explained in part by an association of factors: multiple risks factors, complex infectious history, a high rate of multiple resistance to antibiotics, unfavorable skin conditions

Aim. Gram-negative aerobic bacteria account for 10%-17% of periprosthetic joint infection (PJI). Due to its biofilm-activity, ciprofloxacin plays a key role in the treatment of gram-negative PJI. However, data about treatment outcome of these infections are conflicting. With this retrospective study we aim at evaluating characteristics and outcome of gram-negative PJI. Method. We retrospectively included consecutive patients with gram-negative PJI treated at our institution from 01/2013 to 03/2018. Diagnosis of PJI was defined by the proposed European Bone and Joint Infection Society (EBJIS) criteria. Growth of gram-negative aerobic bacteria was required in synovial fluid, periprosthetic tissue or sonication fluid. Clinical success (infection-free status) was defined as fulfillment of all of the following criteria: (i) unremarkable surgical site and no subsequent surgery (ii) no PJI related mortality and (iii) no long-term antimicrobial suppression therapy of >6 months. Results. A total of 76 patients with gram-negative PJI involving 45 hips, 26 knees, 3 elbows and 2 shoulders were analyzed. The median patient age was 76 years (range, 41–92 years). The route of infection was perioperative in 52 cases, hematogenous in 17 cases and contiguous in 5 cases. The most common isolated pathogens were Escherichia coli (n=31), Klebsiella species (n=17), Proteus species (n=13), Enterobacter species (n=11) and Pseudomonas aeruginosa (n=9). Ciprofloxacin resistance was detected in 20 of 90 (23%) gram-negative pathogens. 21 patients were treated with two-stage revision, 17 with prosthesis retention, 16 with permanent prosthesis removal, 14 with multi-stage exchange and 6 with one-stage revision. In 55 of 71 (77%) patients, ciprofloxacin was included in the treatment regimen. Median follow-up was 10.8 months (range, 1.6–60.7 months) and infection was eradicated in 29 of 47 patients (62%). Among 18 failures, 13 (72%) experienced a new PJI due to another pathogen (n=11) or had negative cultures (n=2), one patient died. The failures occurred after a median of 13.3 months (range, 3.9–28.8 months). All 4 patients with relapse caused by the same pathogen were resistant to ciprofloxacin. Ciprofloxacin-resistance was associated with worse outcome compared to ciprofloxacin-susceptible bacteria (5/13 (38%) vs. 23/33 (70%), p=0.09). Conclusions. The overall outcome of gram-negative PJI was poor (62%). However, most infections were caused by a new pathogen or were culture-negative and occurred after 13.3 months. Ciprofloxacin resistance of the causative pathogen was associated with treatment failure. The reason for the high rate of new PJI is unclear and should be meticulously investigated to improve the outcome

Aim. Revision surgery and debridement and implant retention are recognised approaches for managing prosthetic joint infections (PJI) but may not always be indicated. If the patient is unable to have or declines surgery, prolonged suppressive antibiotic therapy (PSAT) is an option. This study aims to define outcomes of PSAT from a single unit. Method. A retrospective study was performed. All cases of PJI involving the hip or knee between 2012 and 2017 were identified from our institutional database and cross referenced with patient notes. One hundred and seventy eight cases were identified. Of these, 23 (12.9%) (10 hips, 13 knees) were treated with PSAT. Infection was diagnosed based on the MSIS criteria in all cases and all cases were managed by a multidisciplinary team which included specialist microbiologists. One case of long term antifungal therapy was additionally identified. Co-morbidity was assessed using the Charlson co-morbidity index. Exacerbations of infection and need for further surgery were recorded. Results. The mean age was 72 years (Range 35–93 years). The mean Charlson-score was 4.3 (range 1–7). Mean follow up was 24 months (Range 1–54 months). Antibiotics were commenced within 3 months of surgery in 20 cases and between 2 and 4 year following surgery in the remainder. Prolonged antibiotic therapy followed debridement and implant retention in 12 cases, single stage revision in 4 cases and 2 stage revisions in 3 cases. The average number of surgical procedures undergone by each patient prior to starting antibiotic suppression therapy was 1.8 (Range 1–4 procedures). Staphylococcal species were isolated in 13 cases (MRSA 1, MSSA 5, Staph. Epidermidis 5, CONS 1, Staph Pasteuri 1). Escherichia Coli and Streptococci were isolated in 2 cases each. Four cases were due to polymicrobial infection. No organisms were identified in 2 cases. Candida Albicans was identified in 1 case. All cases of infection were treated with prolonged oral antibiotics. Twenty patients (87%) received 6 weeks of intravenous antibiotics prior to commencing prolonged oral antibiotics. Two patients experienced persistent symptoms and required amputation (both TKA). One immunocompromised patient required admission for sepsis related to their infected TKA. The success rate of long term suppressive antibiotics was 87% (20/23) successful at an average 2 year follow up. There was persistent wound discharge in 1 case (4.3%). Conclusions. Prolonged suppressive antibiotic therapy is an effective option for management of PJI and related symptoms with a low incidence of complications in surgically resistant PJI

Introduction. Prosthetic joint infections (PJI) occur infrequently, but due to its increased clinical use represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative staphylococci are the most common infecting agents associated with PJI. A possible therapeutic approach could be the local antibiotic by fluoride-TiO2 nanostructured anodic layers in order to prevent surface colonisation during the early moments after surgery. Here we describe the first results of this model using two common antibiotics. Methods. Fluoride-TiO2 nanostructured anodic layers on Ti6Al4V alloy were produced as described previously by Arenas et al (2013). Discs shaped pieces of Ti6Al4V alloy were loaded with a solution of 150 mg antibiotic (vancomycin or gentamicin)/20 ml sterile distilled water. Samples were immersed in this solution during 24 hours at room temperature with agitation, and then were dried during 48 hours at 20°C. Antibiotic release was studied by introducing both discs in sterile PBS and samples were taken at different times. Samples were then frozen at −80°C until HPLC measurements and biological activity tests using Bacillus subtilis ATCC 6051 (vancomycin) and Escherichia coli ATCC 25922 (gentamicin) were performed. Results. Release kinetic constant was not be obtained by HPLC-UV due to chemical degradation, therefore it was needed to prove biological activity. According to biological activity test, vancomycin and gentamicin estimated concentration mean and standard deviation were 2.9±0.61 and 2.71±0.64 mg/L over time respectively. Conclusions. Fluoride-TiO2 nanostructured anodic layers on Ti6Al4V alloy could be considered as promising vector of antibiotics for the prevention of PJI during early moments after surgery

Aim. We used a polymerase chain reaction (PCR) lateral flow assay1) to rapidly diagnose joint infection. We evaluated the usefulness of multiplex-PCR (PCR lateral flow assay: PCR-LF) using detailed clinical data. Method. A total of 35 synovial fluid samples were collected from 26 patients in whom bacterial infection was suspected, including 22 from knee joints, 11 from hip joints, and 2 from other joints. After purifying the DNA from the samples, multiplex PCR targeting two MRSA-associated genes (femA and mecA) and the bacterial 16S rRNA gene was performed. Amplified gene fragments were specifically detected with DNA probes immobilized on stick devices through DNA-DNA hybridization and visualization, enabling diagnosis of MRSA, MSSA, MRCNS, gram-positive, and/or gram-negative bacterial infection. Genetic identification of bacteria by determining the 16S rRNA gene sequence was also performed using multiplex PCR-positive samples. Finally, the usefulness of our PCR-LF method was evaluated using detailed clinical data. Results. The results of PCR-LF were 9 gram-positive and 1 gram-negative bacterial infections. Eleven bacterial species were identified based on 16S rRNA gene sequences. Ten (90.9%)of the eleven samples (bacterial species) were identified using our PCR-LF. Five samples were detected in bacterial cultures; two are MSSA, one is Streptococcus agalactiae, one is Escherichia coli, one is Prevotella oralis. We diagnosed 6 samples as clinical infections. Therefore, the sensitivity and specificity of the culture tests were 83% and 100%, respectively, while for PCR-LF, these values were 83% and 83%. Conclusions. PCR-LF is highly sensitive and effective for the rapid diagnosis of joint infection; however, dead bacteria may also be detected. Moreover, because the target bacterial species are limited, clinical diagnosis based on the results of multiple examinations is necessary

Aim. Prosthetic joint infections (PJI) are devastating complications after hip arthroplasty and infection rates varies internationally between 0.76% to 1.24%. Hemi-arthroplasty (HA) is the gold standard treatment for dislocated femoral neck fractures. Recently, total hip arthroplasty (THA) has been suggested to generate even better outcomes. However, little is known about PJIs after hip fractures. The purpose of this study was to investigate PJIs after femoral neck fracture in a population-based sample. Methods. Clinical databases were harvested for all THA or HA procedures done for the treatment of femoral neck fractures at our hospital district (HUS) of 1.6 million inhabitants. Altogether, 3693 arthroplasty procedures for hip fractures were performed between 2011 to 2015. The original patient records of each case were reviewed. Complication(s) leading to readmission(s), the microbe(s), and the treatment protocol of each infection was recorded until the closing date (31.12.2016). The definition of PJI according to Musculosceletal Infection Society modified at the International Consensus meeting was used. Results. We detected 111 infections (10 THAs;101 HAs):42 superficial infections (1.1%) and 69 PJIs (1.9%). The PJI rate after THA was 3.7% (8/219) and 1.8% after HA (61/3474) (p=0.04;OR 2.12, 95%CI 1.00–4.49). Most PJIs in THA group (6/8) were treated by debridement, antimicrobials, and implant retention (DAIR) and two by 2-stage exchange. In the HA group the DAIR was the first surgical treatment for 51 PJIs (84%). Other treatment options used were girdlestone (n=3), one-stage exchange (n=2), lavation (n=2), and conservative treatment (n=3). The bacteria cultured at THA group were: Staphylococcus epidermidis (n=4), Staphylococcus aureus (n=3), Streptococcus agalactiae (n=2), and Staphylococcus haemolyticus and at the HA group Staphylococcus aureus (n=25, including 1 MRSA), Staphylococcus epidermidis (n=11), other coagulase negative staphylococci (n=7), Pseudomonas aeruginosa (n=6), Enterococcus faecalis (n=6), Escherichia coli (n=2), and streptococci (n=2). Multiple bacteria were cultured from seven PJIs. The causative microbe was unknown in five PJIs. Conclusion. THA patients had higher rate of PJIs compared to HA, however, the small sample size of the THA group may limit the statistical power of this study. The PJIs after hip fractures were usually treated by DAIR, which is also main PJI treatment after elective THAs. The overall PJI rate was higher among hip fracture than after elective THAs in the literature. The existing trend of treating more dislocated hip fractures with THA may thus lead to increased rated of PJIs in the future

We describe a case series using calcium sulphate bio composite with antibiotics (Cerament/Stimulan) in treating infected metalwork in the lower limb. Eight patients aged 22–74 (7 males, 1 female) presented with clinical evidence of infected limb metal work from previous orthopaedic surgery. Metal work removal with application of either cerement in 5 cases (10–20ml including 175mg–350mg gentamycin) or stimulan in 3 cases (10–20ml including either 1g vancomycin or clindamycin 1.2g or 100mg tigecycline) into the site was performed. Supplemental systemic antibiotic therapy (oral/intravenous) was instituted based on intraoperative tissue culture and sensitivity. Four patients had infected ankle metalwork, 2 patients infected distal tibial metalwork and 2 had infected external fixators. Metal work was removed in all cases. The mean pre operative CRP was 15.8mg/l (range 1–56mg/l). The mean postoperative CRP at 1 month was 20.5mg/l (range 2–98mg/l). The mean pre op WCC was 7.9×10. 9. (range 4.7–10.5 ×10. 9. ). Mean post op WCC at 1 month was 7.1×10. 9. (range 5.0–9.2×10. 9. ). The organisms cultured included enterobacter, staphylococcus aureus, staphylococcus epidermidis, staphylococcus cohnii, stenotrophomonas, acinetobacter, group B streptococcus, enterococcus and escherichia coli. No additional procedures were required in any case. All surgical wounds went on to heal uneventfully. Infection control and union was achieved both clinically and radiologically in all cases. Our results support the use of a calcium sulphate bio composite with antibiotic as an adjuvant for effective local infection control in cases with implant related bone sepsis. The technique is well tolerated with no systemic or local side effects. We believe that implant removal, debridement and local antibiotic delivery can minimise the need for prolonged systemic antibiotic therapy in such cases

Aim. To investigate the antimicrobial activity of a gentamicin-loaded bone graft substitute (GLBGS) in the prevention and eradication of bacterial biofilms associated with prosthetic joint infections (PJI). Method. The GLBGS (17,5 mg gentamicin/ml paste) with 40% hydroxyapatite/60% calcium sulfate. 1. was tested against biofilms of methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, methicillin-susceptible S. aureus (MSSA) ATCC 29213, Escherichia coli Bj HDE-1, S. epidermidis ATCC 12228 and Enterococcus faecalis ATCC 19433. For prevention studies, glass beads and different combinations of GLBGS were co-incubated for 24h at 37°C in CAMH broth with 1–5 × 10. 6. CFU/mL of bacteria. For eradication, biofilms were formed on glass beads for 24h at 37°C in CAMH broth. Then, beads were incubated with different combinations of GLBGS in medium at 37°C for 24h. For microcalorimetric measurements, beads were placed in ampoules and heat flow (µW) and total heat (J) were measured at 37°C for 24h. The minimal heat inhibitory concentration (MHIC) was defined as the lowest gentamicin concentration reducing the heat flow peak by ≥90% at 24h. Results. The GLBGS showed a good activity against all tested strains in both biofilm prevention and eradication. All MHIC values are reported in Table 1. Lower MHICs were observed when GLBGS was tested against E. coli (9.6 µg/mL prevention and 19.2 µg/mL eradication) and S. epidermidis (86 µg/mL and 38.8 µg/mL, respectively). For both prevention and eradication of MSSA, GLBGS MHIC was 631 µg/mL. E. faecalis biofilm formation was prevented with 631 µg/mL and eradicated with double concentration. MRSA showed a higher resistance to GLBGS up to 2516 µg/mL, both in biofilm prevention and eradication. Conclusions. This GLBGS is a valid composite for the prophylaxis and treatment of PJI. Further studies will be performed to evaluate the activity of higher concentrations of GLBGS against MRSA. 1. CERAMENT™|G, BONESUPPORT AB, Sweden

Introduction. The use of irrigation solution during surgical procedures is a common and effective practice in reduction of bioburden and the risk of subsequent infection. The optimal irrigation solution to accomplish this feat remains unknown. Many surgeons commonly add topical antibiotics to irrigation solutions assuming this has topical effect and eliminates bacteria. The latter reasoning has never been proven. In fact a few prior studies suggest addition of antibiotics to irrigation solution confers no added benefit. Furthermore, this practice adds to cost, has the potential for anaphylactic reactions, and may also contribute to the emergence of antimicrobial resistance. We therefore sought to compare the antimicrobial efficacy and cytotoxicity of irrigation solution containing polymyxin-bacitracin versus other commonly used irrigation solutions. Methods. Using two in vitro breakpoint assays of Staphylococcus aureus (ATCC#25923) and Escherichia coli (ATCC#25922), we examined the efficacy of a panel of irrigation solutions containing topical antibiotics (500,000U/L Polymyxin-Bacitracin 50,000U/L; Vancomycin 1g/L; Gentamicin 80mg/L), as well as commonly used irrigation solutions (Normal saline 0.9%; Povidone-iodine 0.3%; Chlorhexidine 0.05%; Castile soap 0.45%; and Sodium hypochlorite 0.125%) following 1 minute and 3 minutes of exposure. Surviving bacteria were counted in triplicate experiments. Failure to eradicate all bacteria was considered to be “not effective” for that respective solution and exposure time. Cytotoxicity analysis in human fibroblast, osteoblast, and chrondrocyte cells exposed to each of the respective irrigation solutions was performed by visualization of cell structure, lactate dehydrogenase (LDH) activity and evaluation of vital cells. Toxicity was quantified by determination of LDH release (ELISA % absorbance; with higher percentage considered a surrogate for cytotoxicity). Descriptive statistics were used to present means and standard deviation of triplicate experimental runs. Results. Polymyxin-Bacitracin, Saline and Castile soap irrigation at both exposure times were not effective at eradicating S aureus or E coli (Figure 1). In contrast, Povidone-iodine, Chlorhexidine, and Sodium hypochlorite irrigation were effective at eradicating both S aureus and E coli. Vancomycin irrigation was effective at S aureus eradication but not against E coli, whereas Gentamicin irrigation showed partial efficacy against E coli eradication but none against S aureus. The greatest cytotoxicity was seen with Chlorhexidine (49.4% ± 1.9). This was followed by Castile soap (33.2% ±3.9), Vancomycin (9.01% ±5.1), Polymyxin-Bacitracin (8.45% ±1.5), and Gentamicin irrigation (4.72% ±2.3) (Figure 2 and Figure 3 microscopy images). Povidone-iodine and Sodium hypochlorite showed least cytotoxicity (0.05% ±0.08 and 0.11%±0.19, respectively). Similar trends were seen at both exposure times and across fibroblasts, osteoblasts and chondrocytes. Discussion. This in vitro study suggests that addition of polymyxin-bacitracin to saline irrigation solution is a futile exercise. Taken within the context of its associated expense, risk of hypersensitivity and impact upon antimicrobial resistance, our findings bring its widespread clinical usage into question. Povidone-iodine may be a more effective option, with a more favorable cytotoxicity profile than the other commonly used irrigation solutions. Clinical outcomes should be studied to determine the most effective agent, concentration, and exposure time for intraoperative irrigation

This study aimed to determine the optimal formulation of antibiotic-loaded bone cement (ALBC) for periprosthetic joint infection (PJI) using both in vitro and in vivo models incorporating various combinations of gram-positive and gram-negative antibiotics. The in vitro antibiotic release characteristics and antibacterial capacities of ALBCs loaded with either 4 g of vancomycin or teicoplanin and 4 g of ceftazidime, imipenem, or aztreonam were measured against methicillin-susceptible S. aureus, methicillin-resistant S. aureus, coagulase-negative staphylococci, Pseudomonas aeruginosa and Escherichia coli. ALBC spacers with superior in vitro antibacterial capacity were then implanted into ten patients (five females and five males between 29 and 75 years of age) diagnosed with chronic hip/knee PJIs and antibacterial activities within joint fluid were measured. The average duration of ALBC spacer implantation was 80 days (range, 36–155 days). Antibiotic concentrations and antibacterial activities of joint fluid at the site of infection were measured during the initial period as well as several months following spacer implantation. Cement samples loaded with vancomycin/ceftazidime or teicoplanin/ceftazidime exhibited equal or longer antibacterial duration against test bacteria as compared with other ALBCs. Joint fluid samples exhibited antibacterial activity against the test microorganisms including ATCC strains and clinically isolated strains. There were no adverse systemic effects, infection at second stage re-implantation, or recurrent infection at final follow-up. Vancomycin/ceftazidime ALBC provided broad antibacterial capacity both in vitro and in vivo and was shown to be an effective and safe therapeutic measure in the treatment of hip/knee PJIs. We thank H.Y. Hsu for performing bioassay

Prosthetic joint infections (PJI) occur infrequently, but they represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative S. epidermidis are the most commonly infecting agents associated with PJI. Nowadays, Gram-negative species like Escherichia coli and Pseudomonas aeruginosa are gaining relevance. The use of TiO2 conical nanotubular doped with fluorine and phosphorous (FP-cNT) surfaces is an interesting approach to prevent surface bacterial colonization during surgery and favouring the osseointegration. Despite of there are serum markers related with PJI, to date there is described no biomaterial-related marker that allows detecting PJI. Here we describe the adherence and the bactericidal effect of FP-cNT and its capacity of marking the non-fermenting bacteria that have been in contact with it by Al. This metal is delivered by FP-cNT in non-toxic concentrations (between 25 and 29 ng/mL). F-P-cNT layers on Ti6Al4V alloy were produced as described previously by our group. Ti6Al4V chemical polishing (CP) samples without nanostructure were used as control and produced as described previously. S. aureus 15981, S. epidermidis ATCC 35984, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 strains adherence study was performed using the protocol described by Kinnari et al. in 0.9% NaCl sterile saline with a 120 min incubation. After incubation, the samples were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Proportion of live and dead bacteria was calculated and studied by using ImageJ software. The experiments were performed in triplicate. The aluminum concentration was estimated in the supernatant after incubation and in the 0.22 µm filtered supernatant by atomic absorption in graphite furnace. The statistical data were analyzed by nonparametric Kruskal-Walis test and by pairwise comparisons using the nonparametric unilateral Wilcoxon test with a level of statistical significance of p<0.05. The values are cited as medians. Our results show that the bacterial adherence of all tested species significantly decreased on FP-cNT compared to CP except P. aeruginosa ATCC 27853: 19.8% for S. aureus 15981, 45.3% for S. epidermidis ATCC 35984 and 8.1% for E. coli ATCC 25922. The bacterial viability decreased 2-fold for S. aureus 15981, and 5-fold for S. epidemidis ATCC 35984, but increased 95% for P. aeruginosa ATCC 27853 and there no was variation for E. coli ATCC 25922 on FP-cNT compared to CP. Only supernatant P. aeruginosa ATCC 27853 shows significant Al detection after 120 min incubation (p<0.05). In summary, F-P cNT is a promising biomaterial that besides favoring osseointegration and potential usefulness as drug carrier, present bactericidal, non-stick ability (at least for staphylococci and E. coli) and is able to mark P. aeruginosa with Al, which could be potentially monitored in serum and urine in patients with PJI

Aim. We describe a case series using adjuvant calcium sulphate bio composites with antibiotics in treating infected metalwork in the foot and ankle. Method. 11 patients aged 22–81 (9 males, 2 females) were treated with clinical evidence of infected limb metal work from previous orthopaedic surgery. Metal work removal with intra osseous application of either cerement in 8 cases (10–20ml including 175mg–350mg gentamycin) or stimulan in 3 cases (5–12ml including 1g vancomycin) into the site was performed. Supplemental systemic antibiotic therapy (oral/intravenous) was instituted based on intraoperative tissue culture and sensitivity. Results. 7 patients had infected ankle metalwork, 2 had infected foot metalwork and 2 had infected external fixators. Metal work was removed in all cases. Mean pre operative CRP was 25.4 mg/l (range 1–137mg/l). Mean postoperative CRP at 1 week was 15.4mg/l (range 2–36mg/l) and at 1 month was 16.1mg/l (range 2–63mg/l). Mean pre op WCC was 8.5×10. 9. (range 6.2–10.6×10. 9. ). Mean post op WCC at 1 week was 8.8×10. 9. (range 5.1–12.7×10. 9. ) and 1 month was 7.1×10. 9. (range 3.7–10.4×10. 9. ). Organisms cultured included enterobacter, staphylococcus species, stenotrophomonas, acinetobacter, group B streptococcus, enterococcus, escherichia coli, pseudomonas, morganella morganii and finegoldia magna. Infection eradication as a single stage procedure with primary would closure and healing was achieved in 10 out of 11 cases (90.9%). No additional procedures were required in these cases. Conclusions. Our results support the use of a calcium sulphate bio composite with antibiotic as an adjuvant for effective local infection control in cases with implant related bone sepsis. The technique is well tolerated with no systemic or local side effects. Our results show that a single stage implant removal, debridement and local antibiotic delivery can achieve over 90% success rates. We theorise that it could minimise the need for prolonged systemic antibiotic therapy in such cases

Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement. . We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary. Cite this article: Bone Joint J 2014;96-B:390–4

Since July 1996, we have treated 97 patients who developed sepsis following total knee arthroplasty and 53 who developed sepsis following total hip arthroplasty. We evaluated the rate of retention of prosthesis. In 69 A-host patients, 80 B-host and 1 C-host, we identified 70 cases of Staphylococcus aureus, 76 of Staphylococcus epidermidis, 33 of Pseudomonas, 23 of Escherichia coli and 18 of Enterococcus. Five patients were diabetic. Muscle flaps were used in 51 cases. Of the 131 patients available for follow-up, 94 healed with retention of prosthesis. Five patients had to undergo amputation. We are still treating 36 patients, some of whom have received a temporary prosthesis. Most patients could be salvaged with a two-staged revision. Host status influenced outcome

Revision surgery and surgery in previously operated areas are associated with an increased infection risk. In such situations, aggressive surgical debridement may be necessary to control and eradicate the infection. Full thickness defects resulting from such debridement present as a challenge. In most cases, an association of various methods, both surgical and non-surgical, is necessary. Our goal is to describe the use of vaccum dressings as an effective way to deal with extensive and infected dorsolumbar surgical defects, while avoiding the use of myocutaneous flaps. This is a retrospective and descriptive case report based on data from clinical records, patient observation and analysis of complementary exams. We present the case of a 57-years-old obese woman with prior history of double approach with posterior instrumentation and spine arthrodesis (D3 to L4) due to severe dorsolumbar adolescent idiopathic scoliosis. She presented to our consult 42 years after surgery, complaining of lower back pain. Clinical observation and imaging exams demonstrated degenerative disc disease in L5-S1 and L5 anterolisthesis. There was also distal instrumentation breakage (right L4 pedicular screw and contralateral rod) with pseudarthrosis suspicion. Distal instrumentation was removed and no pseudarthrosis was found. Therefore, posterior instrumentation and arthrodesis was performed, from L4 to S1. Surgery went without complications. One week after surgery, patient developed fever and inflammatory signs at the surgical incision, with purulent oozing. Escherichia coli and Proteus mirabilis were identified as the causative agents. Decision was made to remove both lumbar and distal dorsal instrumentation and perform aggressive debridement and lavage, with debridement surgery being repeated twice. Finally, a full thickness defect with approximately 20cm long and 6cm wide resulted from the debridement. A vacuum dressing was then applied, for 5 weeks, with progressive decrease in clinical and analytical inflammatory parameters and wound closure. Four months after the initial surgery, patient was discharged with complete defect closure and reepithelialization. This dressing technique provided a sound solution for defect resolution, as well as an important aid for infection control. It proved to be a viable option in an extensive defect, when surgical flap techniques and traditional dressing techniques could not provide a complete solution

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases. Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123mW/cm. 2. irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation was achieved for all Gram positive and negative microorganisms. More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm. 2. , respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae show that gram-negative organisms are also susceptible, though higher doses are required. This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases. Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123mW/cm2 irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation was achieved for all Gram positive and negative microorganisms More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm2, respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae show that gram-negative organisms are also susceptible, though higher doses are required. This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes

We retrospectively reviewed 11 consecutive patients with an infected reverse shoulder prosthesis. Patients were assessed clinically and radiologically, and standard laboratory tests were carried out. Peroperative samples showed Propionbacterium acnes in seven, coagulase-negative Staphylococcus in five, methicillin-resistant staphylococcus aureus in one and Escherichia coli in one. Two multibacterial and nine monobacterial infections were seen. Post-operatively, patients were treated with intravenous cefazolin for at least three days and in all antibiotic therapy was given for at least three months. Severe pain (3 of 11) or severe limitation of function (3 of 11) are not necessarily seen. A fistula was present in eight, but function was not affected. All but one patient were considered free of infection after one-stage revision at a median follow-up of 24 months, and without antibiotic treatment for a minimum of six months. One patient had a persistent infection despite a second staged revision, but is now free of infection with a spacer. Complications included posterior dislocation in one, haematoma in one and a clavicular fracture in one. At the most recent follow-up the median post-operative Constant-Murley score was 55, 6% adjusted for age, gender and dominance. A one-stage revision arthroplasty reduces the cost and duration of treatment. It is reliable in eradicating infection and good functional outcomes can be achieved

The worldwide increase in the resistance of micro-organisms to antimicrobial drugs leads to an increase in morbidity, mortality and health care costs. It is important to identify the resistant organisms, to provide alternative antibiotic treatment protocols and to identify the high-risk infection areas. We undertook a retrospective study of 693 musculoskeletal infections seen in the Musculoskeletal Tumour and Sepsis Unit of Pretoria Academic Hospital over five years, capturing data relating to the microscopy, culture and sensitivity to antimicrobial drugs of micro-organisms from tissue samples and pus swabs. Most infections developed in patients aged 31 to 40 years. Sepsis most often occurred postoperatively. The next most common sepsis followed trauma. The femur was the most common site, followed by the tibia and the knee. In descending order, the most common organisms isolated were Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas sp., Escherichia coli, Enterobacter sp. In the last two years there was an alarming increase in coagulase-negative staphylococci. All micro-organisms exhibited increased resistance to specific antimicrobial drugs over the five-year period

Correct diagnosis of infection is crucial for an adequate treatment of orthopedic implant-related infections. In the orthopedic field, infections can be difficult to diagnose(1). As a consequence, patients may suffer from an undiagnosed and untreated implant-related infection. To solve this problem, we are searching for a diagnostic method to detect these so-called low-grade infections. The technique fluorescence in situ hybridization (FISH) can detect slow-growing and even dead bacteria. Further, as FISH results are available within an hour after tissue collection it is an ideal candidate for diagnostic purposes. AIM: to evaluate the FISH technique for its potential to detect and identify orthopedic infections. Sonication fluid (SF) was collected by sonicating retrieved implants(2) from 62 patients. All samples were subjected to bacterial culture for clinical diagnostics. In addition, a commercially available FISH kit (miacom diagnostics, Germany), specifically designed for blood analysis (hemoFISH Masterpanel), was used. The kit contained 16S rRNA probes (positive control), non-sense probes (negative control), probes for Staphylococcus spp., Staphylococcus aureus, Streptococcus spp., Streptococcus pneumoniae, Streptococcus agalactiae, Enterococcus faecium, Enterococcus faecalis, Enterobacteriaceae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Acetinobacter spp., and Stenotrophomonas maltophilia. All FISH analyses were performed according to the protocol provided with the kit. Culture and FISH results were compared, considering culture as the gold standard. Culture resulted in 27 positive and 35 negative samples. Comparing FISH (16S rRNA probe) with culture, 24 samples tested true-positive and 32 samples true-negative. Furthermore, 3 samples tested false-negative and 3 samples false-positive. The species cultured with the highest incidence were Propionibacterium acnes and Staphylococcus epidermidis, both from 8 SF samples. As the kit did not contain a probe for Propionibacterium acnes, these strains were only detected by the 16S rRNA probe. In addition, the latter samples tested positive with the Staphylococcus spp. probe. Interestingly, 3 samples tested positive with FISH that were culture negative. This result could indicate a higher sensitivity for detection of bacteria with FISH than with culture. Before FISH can be used for diagnostic purposes, the technique needs to be optimized to prevent false-negative results, for use on other patient materials and for detection of bacterial strains relevant for the orthopedic field like Propionibacterium acnes. In conclusion, FISH holds promise to be used as a diagnostic tool for identifying orthopedic infections

Background. Septic knee arthritis is one of the most serious complications after total knee arthroplasty (TKA), and the effectiveness of its treatment affects the patient's quality of life. In our super-aging society, the frequency of TKA in the elderly, often combined with various comorbidities, is increasing. Careful management should be considerd during the management of septic arthritis after TKA in these patients. Purpose. To analyze the clinical features and outcomes of septic arthritis after TKA in our institution. Materials and Methods. Between April 1999 and March 2014, 534 TKAs (osteoarthritis [OA]; 381, rheumatoid arthritis [RA]; 154) were performed. Of these patients, 8 with post-operative infected TKA were retrospectively surveyed. Results. The TKA-associated infection rates were 0.83% (0.35%, OA; 1.7%, RA) during the study period. Five male and 3 female patients were included, with a mean age of 68 years (range, 39–88 years) and primary diagnoses of OA (5) and RA (3). Malignant rheumatoid arthritis (MRA) was present in 1 patient. The infection was affected by a comorbidity in 2 (diabetes mellitus and mixed connective tissue disease). Microorganisms were detectable in 7 patients (methicillin-resistant Staphylococcus aureus [MRSA], 1; methicillin-sensitive Staphylococcus aureus, 2; Streptococcus pyogens, 1; Streptococcus oralis, 1; Escherichia coli, 1; Staphylococcus epidermidis, 1; and unknown, 1) (Fig. 1). The use of the Segawa/Leone classification resulted in 5 patients with type III (acute hematogenous) and 3 with type IV (late) infections. Four patients with type III (80%) infection underwent open debridement, continuous irrigation, and successful implant retention (Fig. 2). The MRA patient had type III infection and an MRSA infection that was treated with two-stage revision, but the infection recurred. We could not perform a re-implantation, and resection arthroplasty was needed. Arthroscopic irrigation in 1 patient with type III infection ended in failure, and open debridement was required. We attempted to retain the implant in 1 patient with type IV infection, but implant removal was required. Three patients with type IV infection underwent two-stage revision successfully. Discussion. The post-TKA infection rate was 0.83% in our institution. Of the implants, 50% (type III, 80%; type IV, 0%) were successfully retained. Early open debridement and irrigation are important for implant retention in patients with infected TKAs, while arthroscopic debridement does not appear to be effective for infected TKA. Implant retention was difficult in the presence of resistant microorganisms. Two-stage revision was required in patients with type IV infection, with a success rate of 75%

With the rising prevalence of HIV, the number of immunocompromised patients is increasing. Higher rates of wound sepsis following implant surgery in seropositive patients have been anecdotally reported in Central and East Africa, but at any single institution experience with HIV and implant surgery is limited. This is a review of 21 patients, 18 of whom were seropositive, who had infected implants after undergoing elective operations for fractures that presented late (mean time 24 months). In 16 patients radiological union had occurred and the septic implants were removed. The organisms cultured in these patients were Staphylococcus aureus and Group-A Streptococcus. In 14 of the patients, implant removal and antibiotics produced excellent results. Two required a Girdlestone excision of the hip and gentamycin beads. Incision and drainage was performed in three patients who had superficial sepsis. The organism cultured was Group-A Streptococcus. All wounds healed. One patient died of AIDS: aspirate revealed Escherichia coli with mixed organisms. In one patient the organism was Pseudomonas aeruginosa and after the nail was removed the patient had a persistent draining sinus. The results suggest that HIV-positive patients are at increased risk of postoperative infection, and that early removal of implants may avoid future septic complications

Introduction. Infection rates following arthroplasty surgery are reported between 1–4%, with considerably higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are over 4 times the cost of primary arthroplasties, with significantly worse functional and satisfaction outcomes. In addition, multiple antibiotic resistant bacteria are developing, so to reduce the infection rates and costs associated with arthroplasty surgery, new preventative methods are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process, and is proven to have bactericidal activity against a wide range of species. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases. Methods. Specimens from hip and knee arthroplasty infections are routinely collected in order to identify possible causative organisms and susceptibility patterns. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (66mW/cm. 2. irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Results. More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm. 2. , respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae has also shown these gram-negative organisms to be inactivated following HINS-light exposure, although higher doses are required. Discussion. This study has demonstrated that HINS-light successfully inactivated clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes

Introduction. Open fractures occur with an annual incidence of 11.5 per 100,000 (6900 pa in UK). Infection rates, even with intravenous broad-spectrum antibiotics, remain as high as 22%. For this reason necessary bone grafting is usually delayed until soft-tissue cover of the bone injury is achieved. A biodegradable bone graft that released sustained high concentrations of antibiotics and encouraged osteogenesis, that could be implanted safely on the day of injury would reduce infection rates and avoid reoperation and secondary grafting. The non –union rate (approx 350 pa in UK) should also be reduced. Such a graft, consisting of a PLA/PGA co –polymer and containing antibiotics, is under development and here we report assessment of spectrum and duration of antimicrobial activity and effect of addition of antibiotics on mechanical properties. Methods. Varying concentrations of gentamicin, colistin, clindamycin and trimethoprim, singly and in combination, were added to the copolymer and test pieces were made. These were then tested using an established method (SPTT) which determines degree and duration of antimicrobial activity as well as risk of emerging resistance. Test bacteria were Staphylococcus epidermidis, Staphylococcus aureus, MRSA and Escherichia coli. Mechanical properties (compressive strength and porosity) were determined using established methods. Results. A combination of gentamicin (4%w/w) and clindamycin (2.5% w/w) gave best results, with inhibitory activity persisting for over 21 days (the target duration) without emergence of resistance. No significant effect of this combination/concentration on mechanical properties was found. Conclusions. The experimental PLA/PGA scaffold containing antibiotics showed activity against the common pathogens of open fractures for a period considered long enough to eradicate contamination acquired at or soon after trauma. At the optimum concentration, they had no significant effect on mechanical properties. In vivo performance is currently being investigated in a sheep model

Introduction. Spondylodiscitis is a combination of discitis and spondylitis. It is very rare to have an isolated discitis without associated vertebral osteomyelitis. It is relatively uncommon in developed nations. However, this disease can lead to severe disability and even death if left untreated. Antibiotics is the mainstay of treatment but cases with neurological compromise would need prompt surgical decompression and stabilisation. Recovery in serious cases is often a lengthy process, requiring long hospital stay. Our unit conducted a review as it is noted spondylodiscitis is becoming more common in elderly and immunocompromised groups. Patients and methods. Retrospective study of spondylodiscitis presented to our unit over the last three years is conducted. Medical records and charts are reviewed, with a focus on disease presentation, risk factors, causative organisms and when surgery becomes necessary. Results. 61 cases are identified, average age 62. Lumbar vertebrae is the most affected region (36%), 15% showed multi-level involvement. Back pain presented in all cases. 75% have at least 1 risk factor. Micro-organisms isolated were Staphylococcus aureus (24.6%), coagulase negative staphylococci (9.8%), methicillin resistant S. Aureus (6.6%), Escherichia coli (6.6%) and mycobacterium tuberculosis (3.3%) and no organism found in 16.4%. 31% of cases required surgical intervention due to neurological deficit or vertebral collapse. 69% were managed conservatively The average inpatient stay was 50 days. CRP decreased as symptoms improve. There is no mortality in this series. Conclusions. We noted a higher than usual presentation of spondylodiscitis in vulnerable patients in our region, often presented late. It is important to recognise this disease early. Once established, patients often require long hospital stay to control disease and regain mobilitiy, even when outpatient anti-biotic therapy is available. A multidisciplinary team approach would be beneficial for the recovery process

There have been a worldwide change in the susceptibility patterns of antibiotics by many community-acquired microorganisms including those associated to wound infection after open fractures. However, the current antibiotic prophylaxis practice adopted by orthopedic surgeons to prevent infectious complications following open fractures has not changed, since Gustilo and Andersen classification was published several decades ago. Few studies have addressed the current pattern of infectious organisms identified in open fracture wounds and its susceptibility to antibiotics that have been empirically used. We aim to study the incidence of community-acquired resistant organisms isolated in lower extremities open fracture and analyze if antibiotic therapy based upon identified resistant pathogens, would decrease surgical site infection (SSI) rates. In a prospective, single center cohort study, from August 2013 to March 2015 at a tertiary public university institution, 136 subjects presenting Gustilo type II or III lower extremities open fractures were randomly assigned in two arms. Both arms were submitted to surgical debridement, fracture stabilization, and empirical antibiotic therapy, but subjects on Group II had at least three samples of tissue cultures collected during debridement. Patients previously treated at an emergency department other them ours were excluded. When resistant bacteria was identified, antibiotic therapy was modified according to antibiogram tests. The primary outcome was to compare the infection rates between these two groups, after early 60-days follow up. We included 136 patients with Gustilo-II (43.4%), –III, (34.5%) open fractures, of which 86% were male, with median age of 33.7 years, and 69.1% presented no comorbidities. Group II (collection of tissue cultures) accounted 36.7% of patients, and among them bacterial growth were detected in 36% (16/50). Microorganism resistant to empirical antibiotic therapy was identified in 18% (9/50), including Staphylococcus aureus, coagulase-negative Staphylococci, Enterococcus sp, Pseudomonas aeruginosa, Klebsiella sp, Serratia sp, Escherichia coli, and Enterobacter sp. Median duration of antibiotic treatment was eleven days. During 60-days of follow up, 71 patients (52.2%) were evaluated for signs of infection using the Centers for Disease Control and Prevention criteria, of which 63.4% (45/71) and 36.6% (26/71) were on Group I and II, respectively. No significant difference in the rates of SSI was observed between the study arms (19.2% vs 22.2%, respectively, P = 0.95). We detected higher rates of bacterial resistance on Gustilo type II and III open fracture wounds, but adjusting antibiotic therapy towards these contaminants did not affected the rates of infection afterwards

Using thermal spraying technique, we developed a novel titanium material coated with hydroxyapatite (HA) containing silver (Ag). In this study, antibacterial activities of the material were examined both in vitro and in vivo. Two different titanium test pieces were prepared. One is the test piece that was coated by HA containing Ag (HA-Ag) and the other is that was coated by HA only, used as a negative control. Antibacterial activity and efficacy of HA-Ag against Staphylococcus aureus, Escherichia coli, and biofilm-forming methicillin-resistant S. aureus (BF-MRSA) was examined by using the Japanese Industrial Standards test (JIS Z2801). Furthermore, surface area where BF-MRSA was attached and proliferated on the test pieces after 24 hours of incubation was calculated by means of scanning electron microscope (SEM). To investigate the antibacterial activity in vivo, the test pieces were inserted subcutisly into the back of SD rats, and BF-MRSA was inoculated into the inserted pieces. On the 7th day after the inoculation, the numbers of adherent bacteria to the pieces were countered by a sterile cotton-tipped swabs method. By the JIS Z2801 test, HA-Ag showed 104 to 105 times stronger antibacterial activity than HA against all bacteria tested in this study. SEM studies revealed the HA-Ag coated material had 30 to 50 times smaller area of attached bacteria than control. In vivo study showed that viable bacterial numbers on surfaces of HA-Ag were 1000 times less than control. These results indicated that the HA-Ag coated materials have antibacterial activities both in vitro and in vivo. Titanium coated with HA containing Ag has a possibility to be a novel antibacterial biomaterial

Introduction. Periprosthetic infections are leading causes of revision surgery resulting in significant increased patient comorbidities and costs. Considerable research has targeted development of biomaterials that may eliminate implant-related infections. 1. This in vitro study was developed to compare biofilm formation on three materials used in spinal fusion surgery – silicon nitride, PEEK, and titanium – using one gram-positive and one gram-negative bacterial species. Materials and Methods. Several surface treated silicon nitride (Si. 3. N. 4. , MC2. ®. , Amedica Corporation, Salt Lake City, UT), poly-ether-ether-ketone (PEEK, ASTM D6262), and medical grade titanium (Ti6Al4V, ASTM F136) discs Ø12.7 × 1mm were prepared or acquired for use in this well-plate study. Each group of discs (n=3) were ultrasonically cleaned, UV-sterilized, inoculated with 10. 5. Staphylococcus epidermidis (ATCC. ®. 25922™) or Escherichia coli (ATCC. ®. 14990™) and placed in a culture medium of phosphate buffered saline (PBS) containing 7% glucose and 10% human plasma on a shaking incubator at 37°C and 120 rpm for 24 or 48 hrs. Coupons were retrieved, rinsed in PBS to remove planktonic bacteria, placed in a centrifuge with fresh PBS, and vortexed. The bacterial solutions were serially diluted, plated, and incubated at 37°C for 24 to 48 hrs. Colony forming units (CFU/mm. 2. ) were counted using applicable dilution factors and surface areas. A two-tailed, heteroscedastic Student's t-test (95% confidence) was used to determine statistical significance. Results. Biofilm adhesion results are provided in Figures 1 and 2 for S. epi. and E. coli, respectively. For S. epi. at 24 hrs, biofilm growth on PEEK was about three orders of magnitude greater than on Ti6Al4V or any Si. 3. N. 4. material (all p<0.005). Ti6Al4V also had more bacteria than the Si. 3. N. 4. samples, but was only significant for as-fired and nitrogen-annealed treatments. Similar trends and significance for S. epi. were observed at 48 hrs. For E. coli, biofilm formation on PEEK was significantly greater than all other materials at both 24 and 48 hrs. Bacterial growth on Ti6Al4V was also statistically greater than all Si. 3. N. 4. conditions, with the possible exception of nitrogen-annealed Si. 3. N. 4. By 48 hrs, PEEK remained 2 orders of magnitude above Ti6Al4V, and 2.5–3 orders of magnitude greater than the Si. 3. N. 4. conditions. Ti6Al4V was also significantly greater than all of the Si. 3. N. 4. treatments at 48 hrs. Discussion. Si. 3. N. 4. , PEEK, and Ti6Al4V surfaces demonstrated significant differences in bacterial adhesion and proliferation for both gram-positive S. epi. and gram-negative E. coli, particularly at 48 hrs post-inoculation. The various Si. 3. N. 4. samples showed the most favorable bacterial resistance for both species tested. The exact mechanism of the bacteriostatic behavior of Si. 3. N. 4. is still under investigation; but it may result from chemical interaction with the material's surface to form peroxynitrite (a powerful oxidative agent). 2. Conclusion. Identifying biomaterial surfaces that resist biofilm adhesion is an important emerging strategy in addressing implant-related infections. Si. 3. N. 4. is a new biomaterial with the apparent potential to suppress biofilm formation

Aims: The present experiment addressed the question whether lipopolysaccharides (LPS), hip joint tamponade or their combination modulate hip perfusion. Methods: 16 immature Danish Landrace pigs of both genders were treated in 3 groups. 4 animals received LPS from escherichia coli intravenously 4 hours previous to hip joint tamponade. 8 pigs underwent the hip operation without previous medication. 4 animals without treatment served as control group. Blood ßow measurement was done by the Radioactive Tracer Microspheres technique. Results: Femoral head epiphyseal blood ßow decreased signiþcantly during hip joint tamponade. Reperfusion occurred to a level not signiþcantly differing from that before ischemia, whereas epiphyses remained ischemic in 2 pigs. The hip joint capsule showed signiþcant hyperperfusion during and after joint tamponade. No signiþcant difference was revealed comparing the LPS-treated and non-treated groups of pigs in all hip regions (p = 0.79, U-test). In addition, in the LPS-group, none of the femoral head epiphyses remained ischemic. Conclusions: LPS and hip joint tamponade, which have separately been discussed as pathomechanic factors of Non Traumatic Femoral Head Necrosis, have been combined in a bifactorial porcine model. Systemic lipopolysacchrides as bacterial endotoxin have no acute effect on regional hip perfusion which would make a consequent osteonecrosis probable. 6hourly hip joint tamponade alone evoked non reperfusion in 2 out of 8 pigs and a prolongation of the 6 hours ischemia might evoke more cases of non reperfusion

Prosthetic joint infection (PJI) is an increasing problem and management commonly involves prosthesis removal with serious consequences. Biofilm-forming staphylococci are the most common causative organisms with Staphylococcus aureus being most virulent and methicillin-resistant Staphylococcus aureus (MRSA) more than doubling the infection mortality rate. Bacterial adhesion is an essential primary event in biofilm formation and infection establishment. The development of a novel combination vaccine programme to prevent staphylococcal PJI by directing antibody against factors involved in adhesion and biofilm formation, and investigation of S. aureus binding-domains as potential vaccine components for adhesion inhibition is described. Selected target antigens included the S. aureus fibronectin-binding protein (FnBP) and iron-regulated surface determinant (IsdA), which have been shown to be important for infection establishment and predominantly bind to host fibronectin and fibrinogen respectively. Escherichia coli clones harbouring recombinant S. aureus binding-domain DNA sequences were used for expression and purification of antigen domains. In vitro antibody evaluation determined whether immune inhibition of bacteria - ligand binding can significantly impact on attachment to plasma-conditioned biomaterial (in presence of other bacterial ligands). Adhesion of homologous and heterologous (MRSA PJI isolate) S. aureus to plasma-conditioned steel was significantly reduced (approximately 50 percent average reduction, p < 0.0001) when pre-exposed to anti-rFnBP-A antiserum (with pre-immune serum control) that was 50-fold more dilute than the actual titre from immunisation. Inhibition was related to ligand presence but not staphylococcal Protein A, and reduced adhesion was not observed with the mutant strain, indicating specific inhibitory antibody involvement, and demonstrating for the first time the potential of rFnBP-A for prevention of S. aureus PJI. Adhesion-inhibitory activity was also observed with a purified IgG-fraction of rIsdA antiserum but this activity appeared to be masked by non-IsdA - related interactions when non-IgG - purified antiserum was assessed

Introduction: Arthrography and synovial fluid punction are two investigations easily combined as a diagnostic tool for the detection of (a)septic loosening of arthroplasties: diagnostic imaging; X-ray guided injection of iodine-containing contrast agents in (artificial)joints and synovial fluid puncture for microbiological diagnostics. The contrast agent is present in the fluid puncture for culturing. Free iodine is bactericidal, hence the assumption that the iodine causes fault negative culture results. The older literature (1960–1982) partially supports this assumption and iodine contrast agents have been modernized considerately. Is the effect the modern contrast agents have on the micro-organisms the cause of the fault negative culture results?. Method: The influence of modern widely used iodine containing contrast agents (Omnipaque. 1. , Visipaque. 2. , UltraVist. 3. , Xenetix. 4. ) and two 30 year old agents (Hexabrix. 5. en Telebrix. 6. ) on the growth of the following relevant prosthesis infection causing micro-organisms were examined:. Staphylococcus aureus. Staphylococcus epidermidis. Enterococcus faecalis. Streptococcus pyogenes. Bacillus cereus. Escherichia coli (E. coli). Pseudomonas aeruginosa. Candida albicans. Corynebacterium jeikeium. Propionibacterium acnes. Three different techniques were used: a disk diffusion test (classical resistance determination) and time-killing curves tests with a high inoculum (1,5*108 cfe/ml) and a low inoculum (10*3 cfe/ml) at 0, 2 and 24 hours. Results: Disk diffusion tests: no contrast agent affected the growth of micro-organisms. The high and low inoculum tests: only the combinations Telebrix with both P. aeruginosa and E. coli showed any growth inhibition but a non-significant (p = 0.07) growth inhibition of log-1. This however, did not impede the detection of these bacteria. And with all other combinations there was no significant inhibition compared to the saline control and in every combination the percentage surviving number of bacteria was always higher than 30%. Conclusion: Modern contrast agents do not seem to have a significant inhibitory effect on micro-organisms. They do not seem to be the cause of the fault negative synovial fluid culture results

Aims: To evaluate the value of 99mTc-labeled mono-clonal Fab antibodies (Leukoscan) in the diagnosis of septic loosening of total hip arthroplasty (THA). Methods: 16 patients (mean age 63.2 years) with hip arthroplasty (5 hemi,9 cementless,2 cemented THAs) were investigated for deep infection with the use of Leukoscan. Patient selection was based on a “high-risk protocol”. All patients were clinically evaluated using modified HHS and each patient’s workout included x-rays, WBC, ESR, CRP, dynamic bone scan 99mTc-MDP and Leukoscan. Two (2) patients were treated by wide debridement and continuous lavage,6 with revision surgery and 8 with Girdlestone. Histologic samples and cultures were received and their results were compared with Leukoscan’s findings. Results: Preoperative evaluation of the patients revealed as major risk factors:pathologic blood tests (16), previous surgical interventions (13), implant loosening (8), wound infection (7). Mean mHHS was 58 (28–80), mean ESR 51 (23–87 mm/h), mean CRP 4,1 (0,9–18 mg/dl). Bone scans were evaluated as 15 positive and 1 negative and they were matched with 15 positive and 1 negative Leukoscan respectively. Twelve (12) positive histopathologic results and 2 positive tissue cultures were matched with 14 positive Leukoscans, while 1 positive Leukoscan was not verified by positive histopathologic findings of chronic infection. Bacteriae identified were: S.epidermidis 5x, S.aureus 2x, Escherichia Coli 1x, S.saprophyticus 1x, Klebsiella pneumoniae 1x. Conclusions: Leukoscan seems to offer a reliable diagnostic tool for investigation of septic bone infection in presence of hip arthroplasty, presenting a senstitivity of 100% and spesitivity of 93,75%. Proper patient selection, based on diagnostic criteria and risk factors is essential

Summary. Prosthetic UHMWPE added with vitamin E and crosslinked UHMWPE are able to decrease significantly the adhesion of various bacterial and fungal strains limiting biomaterial associated infection and consequent implant failure. Introduction. Polyethylene abrasive and oxidative wear induces overtime in vivo a foreign-body response and consequently osteolysis, pain and need of implant revision. To solve these problems the orthopaedic research has been addressed to develop new biomaterials such as a crosslinked polyethylene with a higher molecular mass than standard Ultra High Molecular Weight Polyethylene (UHMWPE), and consequently a higher abrasive wear resistance and an antioxidant (vitamin E)-added UHMWPE to avoid oxidative wear. Nevertheless a feared complication of implant surgery is bacterial or fungal infection, initiated by microbial adhesion and biofilm formation, and related to the biomaterial surface characteristics. Staphylococci are the most common microorganisms causing biomaterial associated infection (BAI), followed by streptococci, Gram-negative bacilli and yeasts. With the aim to prevent BAI, the purpose of this study was to evaluate the adhesion of various microbial strains on different prosthetic materials with specific surface chemical characteristics, used in orthopaedic surgery. Methods. We compared the effects of vitamin E-added UHMWPE and crosslinked UHMWPE with that of standard GUR 1020 UHMWPE, upon the adhesion of ATCC biofilm-producing strains of Staphylococcus epidermidis, S. aureus, Escherichia coli and Candida albicans. After different incubation times the samples were sonicated to release the attached microorganisms and spread onto agar to quantify colony forming units (UFC)/ml. The biomaterials were physico-chemically characterised by means of scanning electron microscopy (SEM), water contact angle (CA) measurements and attenuated total reflectance (ATR)-fourier transform infrared (FTIR) spectroscopy, before and after adhesion assays. The experiments were assayed in triplicate and repeated a minimum of three times. A statistical analysis on results was conducted. Results. No significant difference of the surface roughness, CA and ATR-FTIR spectroscopy was found among the different biomaterials. After 3 and 7 h of incubation microbial adhesion rates were similar with no statistically relevant differences among the samples assayed. On the contrary, after 24 and 48 h of incubation a significantly (p<0.05 and p<0.01) different adhesion trend was achieved on the three biomaterials, highlighting a microbial adhesion significantly lower on vitamin E-added UHMWPE and crosslinked UHMWPE compared with that on standard UHMWPE. Discussion/Conclusion. Standard UHMWPE, vitamin E-added UHMWPE and crosslinked UHMWPE were chosen because of their diffusion in the clinical use. Previously we showed that vitamin E addition to the UHMWPE reduces the adhesive ability of various staphylococcal strains, compared with standard UHMWPE, and we correlated this results with its antioxidant properties. The results of this study indicate a quite similar significant reduction of bacterial and fungal adhesion on either vitamin E-added UHMWPE and crosslinked UHMWPE, if compared to standard UHMWPE at 48h. Further analysis on the chemical- physical characteristics of the UHMWPE surfaces and on their morphology are needed to explain the different adhesions

We retrospectively analysed three hundred and one infected total hip replacements. Infection was defined on the basis of the surgeons clinical impression. This included a thorough history and physical examination, laboratory and radiographic evaluation. Peri operative findings were also taken into consideration. Despite the overt appearances of sepsis fifty seven of these three hundred and one cases demonstrated no bacterial growth. These were excluded from the microbiological analysis. The remaining two hundred and forty four cases oven bacteriological evidence of deep infection. Thirty seven cases grew two different organisms both of which were felt to be clinically significant. The remainder grew a single organism. Hence a total two hundred and eighty one bacteriological isolates were grown. Coagulase negative staphylococcus accounted for 54.8%, staphylococcus aureus 13.5%, streptococci 8.9%, Escherichia coli 6.1% and diptheroids 2.5%.These organisms were plated out in a standard fashion against a variety of antimicrobial agents. We analysed ten antibiotics and their sensitivity profiles against the spectrum of organisms demonstrated by this series. Best antimicrobial coverage by a single antibiotic was afforded by fucidic acid (85.3%) and erythromycin (79.6%). Gentamicin was found to be sensitive to only 76.1% of the bacteria present at the time of revision for deep infection. Combining gentamicin with other antibiotics improved the theoretical coverage. A combination of gentamicin and fucidic acid demonstrated a 97.5% coverage. Gentamicin with erythromycin gave 95.2%. When treating the infected arthroplasty it may be beneficial to add extra antibiotics to bone cement. This may either be to the cement spacer in a two stage revision or to the definitive cement in a single stage revision. We would suggest that fucidic acid or erythromycin would be good candidates for this. These candidates should also be considered when designing the next generation of combination antibiotic acrylic bone cements

Despite the in-depth research into the treatment of acute septic arthritis of the knee, the morbidity and mortality are still significant. The purpose of our study was to evaluate the efficacy of a treatment protocol including arthroscopic irrigation and debridement in resolving septic arthritis of the knee. During a 6-year period, 18 patients presenting with septic arthritis of the knee were included in this study. In 10 cases, septic arthritis occurred after knee arthroscopy, in 2 after open trauma, in 2 more after joint aspiration or injection; there were 2 hematogenous infections and 2 following contiguous spread from an adjacent site. The patients were treated with an arthroscopic debridement protocol consisting of (1) arthroscopic debridement and synovectomy, (2) suction drainage for 24 hours, (3) repeat arthroscopy for persisting clinical and laboratory findings and (4) antibiotics IV for four weeks and per.os. for two months (ciprofloxacin – rifampicin). The onset of the symptoms presented 18.2 days in average after the cause. The patients complained of swelling (18/18), fever ~39° C (16/18), stiffness (13/18), pain (12/18), erythema (6/18) and weakness (6/18). Arthroscopic drainage (average 1.5 procedures) was performed at an average of 8.4 days from the initiation of the symptoms. Laboratory data revealed elevated ESR (erythrocyte sedimentation rate) (average 68.9), CRP (average: 10.9) and WBC (average: 8894.3). The mean follow-up period was 3.5 years. Cultures from knee joint aspirations were negative in 9 cases. Five knees were infected with Staphylococcus aureus, 2 with Staphylococcus epidermidis, 1 with Escherichia Coli and 1 with multiple organisms. One month after the last arthroscopic debridement, the ESR and CRP levels were normalised in all cases. Lysholm scores averaged 91. Most of the patients (15/18) returned to their pre-infection level of functioning. Overall success in clinical eradication of infection was 100%. Our conclusions are:. early aggressive arthroscopic debridement as part of a treatment protocol can be an effective treatment option,. time is a crucial factor, and. the earlier the arthroscopic debridement is performed, the better results are obtained

Objective: To compare the in-vitro antimicrobial action of surgical irrigation fluids: 0.9% saline, 2g/L cephradine, 80mg/L gentamicin, 10% povidone-iodine (PVP-I) and 40ppm aqueous iodine (laq) for activity against Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli in the presence of blood, plasma and saline. Materials and Methods: 5mL of antimicrobial agent was added to 5ml of blood, plasma or saline containing 10. 5–. 10. 6. CFU/mL of the test bacterium. At 15 seconds, 1 minute, 5 minutes, 1 hour and 2 hours, a 1mL sample was inactivated in 9mL of 0.5% sodium thiosulphate. The bacterial numbers were determined using a biochemical assay (Chemiluminescence) with a calibration curve and by spread plate counts. The data were transformed by a logarithmic function and analysed by linear regression to give 95% confidence intervals for their gradient of change over 2 hours. Significant differences were defined at the 5% level. Results: In saline. All bacteria were killed within 15 seconds with PVP-I and Iaq, but showed no significant reduction with saline, cephradine or gentamicin. In plasma. E. coli was killed within 15 seconds with all irrigation fluids. S. aureus and S. epidermidis showed no significant reduction with saline, Iaq or cephradine, but did show a significant reduction in the presence of gentamicin. With PVP-I, all S. epidermidis were killed within 15 seconds and all S. aureus within 5 minutes. In blood. E.coli with PVP-I, Iaq and cephradine showed no significant reduction. E. coli with gentamicin did show a significant reduction. Both staphylococci showed a significant reduction over 2 hours with PVP-I and gentamicin, but no significant reduction with saline, cephradine and Iaq. Conclusions: As blood has a strong chemical inactivating effect on iodine – based formulations, Iaq and PVP-I cannot be recommended for surgical irrigation. Gentamicin should be used in preference to cephradine in surgical irrigation fluids if an antimicrobial agent is required. The residual immunological components (particularly complement) in blood and plasma may enhance the susceptibility of bacteria to antimicrobial agents

Introduction: Tumours of sacrum are rare. Treatment depends on malignancy or local aggressiveness: resection is indicated for malignant lesions, intralesional surgery for benign. Purpose of this study was to analyse risk of infection and its treatment after surgery for the two most common primary sacral tumours. Material and Methods: Between 1976 and 2005, 82 patients with sacral chordoma or giant cell tumour were treated in our Institution. Demographic data, surgery and adjuvant treatments were analysed in the two histotypes. All patients were periodically checked with imaging studies. Special attention was given to the assessment of deep infections, their treatment and outcome. Patients included 44 females and 38 males, ranging in age from 14 to 74 years. Mean follow-up was 9.5 years (min. 3, max. 27). Histopathological findings included chordomas in 55 cases and giant cell tumor (GCT) in 27. Most pts. had iv antibiotic therapy with amikacin and teicoplanin. Surgery of chordoma was resection, surgery of GCT was intralesional excision. In 6 sacral resections a miocutaneous transabdominal flap of rectus abdominis was used for posterior closure. Results: No deep infections were observed in the GCT series. Three patients with sacral chordoma died for postoperative complications and were excluded from this analysis. Of the remaining 52 patients with chordoma, 23/52 had deep wound infection (44%), that required one or more additional operative procedures. In 16 pts. (70%) infection occurred within 4 weeks postoperatively, in 7 within 6 months. Most frequent bacteria causing infection were Enterococcus (23%), Escherichia Coli (20%), Pseudomonas Aeruginosa (18%). In 74% of cases a multiagent infection was detected. Surgical treatment consisted in 1 (52%) or more (48%) surgical debridements, combined with antibiotics therapy according to coltural results. Mean surgical time was 14 hours for resections and 6 hours for excisions. No significant difference was found comparing deep wound infections with levels of resection (15/33 resections proximal to S3-45% and 8/19 resections below or at S3-42%), previous intralesional surgery elsewhere (4/9 patients previous treated elsewhere-44% and 19/46 primarily treated patients-41%) and age at surgery. Conclusions: Type of surgery was the prominent factor related with a major risk of infection. Operating procedure time correlated as well. Resection of sacral chordomas with wide margins improves survival although extensive soft-tissue resection in proximity to the rectum favours deep infections. Intralesional excision is the recommended surgical treatment for GCT of the sacrum and does not imply a significant risk of infection

Introduction: The emergence of multidrug resistant Gram negative bacilli susceptible to hardly any beta lactam compound has led to infections close to a therapeutic dead end. In such circumstances, Imipenem-cilastatin (I-C) is often the only remaining therapeutic option. We report our experience with the prolonged administration of high-doses of I-C in the treatment of osteoarticular infections with bacteria resistant to other beta-lactam agents (or 4. l. generation cephalosporins in 14 cases). Materials and methods: Our retrospective study over 7 years included 29 patients with septic arthritis (n=3) continuous osteitis (n=6), septic non-union(n=12) and prosthetic joint infections (n=8). Treatment included an extensive surgical debridement and post-operative combination antibiotherapy with intravenous I-C and aminoside (54%) and/or fluoroquinolones (46%) and/or fosfomycin (29%). Associated microorganisms requiring yet additional antimicrobial agents were associated in 17 (59%) cases. I-C was maintained for an average of 46 days (extremes 21–90), at an average dose of 3,8g/day (extremes 2–6). The bacteria warranting I-C were cephalosporinase hyperproducing Enterobacter cloacae (38%), extended spectrum beta-lactamases producing enterobacteria (31%), Pseudomonas aeruginosa (21%) and/or Acinetobacter baumanii (21%). Results: Early outcome was favorable in 24 patients (82%). Two patients relapsed with the bacteria requiring I-C. Three failed to negate succion fluid cultures : one was discharged with no change in his condition, one agreed to a leg amputation and the third died of candidemic septic shock in SICU with drainage fluid still bactériologie ally positive. Repeated secondary colonization and systemic infection with yeasts led to a monitoring of yeast load. Per os amphotencin B and immediate treatment of urinary colonization prevented further systemic dissemination of candical infections. No other tolerance incidents were noted. Acquired resistance occurred only once in a P. aeruginosa isolate while Imipenem-cilastatin was chosen to cover an ESBL producing Escherichia coli. Secondary treatment with ceftazidime was then successful in eradicating P. aeruginosa. Conclusion: I-C has been widely used for the treatment of mixed flora infections as a wide spectrum antibiotic. We report good tolerance of high posology long term administration in documented osteoarticular indications if yeast colonization is properly monitored, and eradication rates are comparable to those reported in infections with susceptible bacteria

Bacterial infections related to orthopaedic implants is one of the serious types of complications. Recently, there has been a greater interest in antibacterial biomaterials. However, antibacterial evaluations of each material are inconsistant, so intercomparison of the antibacterial performance is difficult. This study focused on the Japanese Industrial Standards test (JIS Z2801), which is used for antibacterial evaluation of commodities. The study investigated a suitable evaluation method for in vitro antibacterial activity of biamaterials. In 2007, JIS Z2801 test was approved as international standard ISO 22196. Hydroxyapatite (HA) powder containing 3 wt % of silver oxide (Ag) was sprayed on the surface of titanium disks with the thermal spraying method, using an acetylene torch. This coating has been proved to generate strong antibacterial activity in previous studies. The antibacterial activity was examined with the JIS Z 2801 test and modified JIS Z2801 test. The bacterial strains used in JIS Z2801 test were Escherichia coli (E.coli), Staphylococcus aureus (S.aureus). Bacterial culture medium was instilled onto the surface of the test disks (about 106 cells/ml) and covered with polystyrene films. After cultivation in 1/500 Nutrient Broth for 24 h at 35°C, the bacteria was washed out with the broth. The numbers of viable bacteria in the broth were counted with the agar plate culture method. Additionally, Modified JIS Z2801 test was performed. Modified points were added to the bacterial strain of biofilm-forming methicillin-resistant S.aureus (BF-MRSA), using Fetal Bovine Serum (FBS) as a culture medium, and cultivated at 37°C. In the JIS Z2801 test, Antibacterial activity values of the HA-Ag disk were composed against E.coli 4.1 and S.aureus 5.0. In the modified JIS Z2801 test, antibacterial activity values against E.coli, S.aureus and BF-MRSA were 8.2, 5.5, and 7.1. When this value is greater than 2.0, it shows there is antibacterial activity. The titanium disk coated with HA-Ag showed antibacterial activity in both tests. The JIS Z2801 test is designed to evaluate comodities in poor nutritional environment. However, the environment in the body is eutrophic. It is easy to make bacterial growth. For this reason, it is necessary to consider evaluating for biomaterials with suitable method considered in vivo. In this study, to examine the condition like that found in the body, we cultivated FBS at 37°C. In addition, the antibacterial activity against BF-MRSA was examined to consider the bacterial infection related to orthopaedic implants. The modified JIS Z2801 test showed that it is a suitable evaluation method for in vitro antibacterial activity of biomaterials

In the period from 1999 to 2003 bacterial contamination of explanted cadaver bones and tendons from the Regional Tuscan Tissue and Cell Bank was studied. During this period 1124 explants from 402 donors were taken, of which 311 donors whose heart was beating and from 91 whose heart was not beating. The bone explantation procedure followed a standardized protocol. Al the samples were explanted in the operation room by a team of two surgeons and a nurse during the first 24 hours after death. The protocol concerning the sterility of the explanting procedure was standardized and followed accurately. The bacteriological examination was performed immediately after the explantation and before the samples were treated with antibiotic solution. Three different tests were used: superficial microbiological swabs of the bone surface, one from the medullar canal and a small bone or soft tissue sample. The samples were inoculated immediately in culture medium and incubated for at least 10 days. From 1124 explanted samples 430 were contaminated: 99 with pathological bacteria such as Staphylococcus aureus, Enterococcus, Escherichia coli etc., 331 with nosocomial bacteria such as coagulase neg. Staphylococcus, Corynebacteria, etc. The samples that were contaminated with pathological bacteria were excluded from the study. The other contaminated group was re-processed and re-tested for contamination. The factors influencing the results of contamination were anatomical location of the explants and the experience of the surgical team. In contrast, the donor type (heart beating vs. heart not beating) did not play any role. From 1999 to 2003 the University Hospital of Careggi in Florence, Italy, used 721 explants from which 624 were retrieved from the Regional Tuscan Tissue and Cell Bank, 72 from foreign banks and 14 from another national bank. The explants from foreign banks were all re-tested according to our standards. Among those, 699 samples were sterile and 22 samples (3%) were contaminated. Seventeen (2.3%) of the 22 samples were contaminated with pathological bacteria with low morbidity and 5 (0.7%) with medium morbidity. Compared to the control group contamination of the explants retrieved from the Regional Tuscan Tissue and Cell Bank was 2.8%. However, the contamination of samples of an explant is not necessarily correlated with a true infection of the specimen. This study shows that factors such as retrieval techniques, contamination factors in the operating room and laboratory mistakes can cause false-positive contamination results. In fact, only three of 604 patients who were operated in major orthopaedic procedures using bone and soft tissue allografts developed clinical evidence of infection (0.5%). In conclusion, the infection rate of our allografts in this study is not higher than the standard infection risk of any other major orthopaedic procedure (0.5%)

Use of allograft bone has become standard for bridging defects unlikely to heal by simple fixation and routinely used in revision arthroplasties for implant stabilization. Unfortunately, this decellularized allograft provides an ideal surface for bacterial colonization, necessitating repeated surgeries, extensive debridement and lengthy antibiotic treatments. With up to 18% infection rate following allograft surgeries, a need for more effective means to prevent this process is evident. We describe a novel modification of native bone allografts that renders their surface bactericidal while increasing the effectiveness of systemic antibiotic treatments. Allograft modification: Morselized human bone was washed extensively and sequentially coupled: 2X with Fmoc-aminoethoxyethoxyacetate (Fmoc-AEEA); deprotected with 20% piperidine in Dimethylformamide (DMF); and then coupled with vancomycin (VAN) for 12–16 hours. The VAN-bone was washed extensively with DMF and PBS for at least 1 day. VAN immuno-fluorescence: Control or VAN-bone was washed 5X with PBS, blocked with 10% FBS (1hr), incubated with rabbit anti-VAN IgG (4oC, 12h) followed by an Alexa-Fluor 488-coupled goat anti-rabbit IgG (1hr), and visualized by confocal laser microscopy. Antibiotic Activity. Equal dry weights of control and VANbone were sterilized with 70% ethanol, rinsed with PBS, and incubated with either Staphylococcus aureus (S. aureus) or Escherichia Coli (Ci=104 cfu) in TSB, 37oC, for 2, 5, 8 and 12 hrs. Antibiotic treatment: Clinical grade vancomycin was added to the solution with bacteria or following infection at a final concentration of 10μg/ml. Bacterial counts: Non-adherent bacteria were removed by washing and adherent bacteria suspended by sonication in 0.3% Tween-80 for 10mins followed by plating on 3M. ®. Petrifilms. Bacterial visualization: Non-adherent bacteria were removed by washing extensively with PBS and adherent bacteria stained with the Live/Dead BacLight Kit (20mins, RT) to cause viable bacteria to fluoresce green. Samples were visualized by confocal microscopy. In comparison to controls, VAN-bone consistently reduced the graft bacterial load by ~90% at all time points. After staining and visualization of adherent bacteria, biofilm formation was apparent on controls by 12 hrs and absent from VAN-bone. E.coli, a gramnegative organism that is not sensitive to VAN, readily colonized both control and VANbone, confirming retention of VAN specificity. We then evaluated VAN-bone activity in a system that modeled systemic antibiotic therapy and antibiotic prophylaxis. In the absence of solution antibiotics, VAN-bone exhibited a significant decrease in bacterial colonization as compared to controls. When 10 μg/ml VAN was added to the medium for the last 4 h (modeling systemic antibiotic therapy), colonization of control surfaces was reduced, while colonization of VAN-allograft was almost eliminated. When 10 μg/ml VAN was added concomitantly with S. aureus, VAN-bone colonization was undetectable, while colonization of control surfaces still occurred. We have previously described an antibiotic-tethered allograft that resists bacterial colonization. In this abstract, we test this technology with an vitro model of bone implantation in the presence of solution antibiotics. In these models, solution antibiotics failed to prevent infection of control bone while completely clearing the bacteria on VAN-bone. Furthermore, VAN bone exhibited high activity against S. aureus, a gram positive organism, whereas it was ineffective against E. coli, a gram negative organism. The specificity of the tethered antibiotic supported the view that the antibacterial properties of the allograft were related to the tethered antibiotic and not to undefined aspects of the attachment chemistry. In terms of antibacterial activity, when challenged with 104 CFU S. aureus (with concentrations reaching > 107 CFU by 24 h), the antibiotic -modified allograft consistently decreased bacterial colonization by > 90%; S. aureus inocula < 102 CFU resulted in no detectable colonization of the VAN-allograft. Thus, development of these allografts may not only combat allograft colonization but increase the effectiveness of prophylactic antibiotics to ultimately result in a new therapy for allograft-associated infection

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Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models.

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Musculoskeletal infection is a devastating complication in both trauma and elective orthopaedic surgeries that can result in significant morbidity. Aim of this study was to assess the effectiveness and complications of local antibiotic impregnated dissolvable synthetic calcium sulphate beads (Stimulan Rapid Cure) in the hands of different surgeons from multiple centres in surgically managed bone and joint infections.

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This study was designed to characterize the recurrence incidence and risk factors of antibiotic-loaded cement spacer (ALCS) for definitive bone defect treatment in limb osteomyelitis.

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We aimed to evaluate the utility of ⁶⁸Ga-citrate positron emission tomography (PET)/CT in the differentiation of periprosthetic joint infection (PJI) and aseptic loosening (AL), and compare it with ^99mTc-methylene bisphosphonates (^99mTc-MDP) bone scan.

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Septic arthritis of the hip often leads to irreversible osteoarthritis (OA) and the requirement for total hip arthroplasty (THA). The aim of this study was to report the mid-term risk of any infection, periprosthetic joint infection (PJI), aseptic revision, and reoperation in patients with a past history of septic arthritis who underwent THA, compared with a control group of patients who underwent THA for OA.

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The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid.

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Management of displaced paediatric supracondylar elbow fractures remains widely debated and actual practice is unclear. This national trainee collaboration aimed to evaluate surgical and postoperative management of these injuries across the UK.

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Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections.

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Implant-related postoperative spondylodiscitis (IPOS) is a severe complication in spine surgery and is associated with high morbidity and mortality. With growing knowledge in the field of periprosthetic joint infection (PJI), equivalent investigations towards the management of implant-related infections of the spine are indispensable. To our knowledge, this study provides the largest description of cases of IPOS to date.

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A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach.

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The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB.

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Current diagnostic tools are not always able to effectively identify periprosthetic joint infections (PJIs). Recent studies suggest that circulating microRNAs (miRNAs) undergo changes under pathological conditions such as infection. The aim of this study was to analyze miRNA expression in hip arthroplasty PJI patients.

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Biofilm infections are among the most challenging complications in orthopaedics, as bacteria within the biofilms are protected from the host immune system and many antibiotics. Halicin exhibits broad-spectrum activity against many planktonic bacteria, and previous studies have demonstrated that halicin is also effective against Staphylococcus aureus biofilms grown on polystyrene or polypropylene substrates. However, the effectiveness of many antibiotics can be substantially altered depending on which orthopaedically relevant substrates the biofilms grow. This study, therefore, evaluated the activity of halicin against less mature and more mature S. aureus biofilms grown on titanium alloy, cobalt-chrome, ultra-high molecular weight polyethylene (UHMWPE), devitalized muscle, or devitalized bone.

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This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%).

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The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI.

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Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI).

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A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients.

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This aim of this study was to analyze the detection rate of rare pathogens in bone and joint infections (BJIs) using metagenomic next-generation sequencing (mNGS), and the impact of mNGS on clinical diagnosis and treatment.

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CRP is an acute-phase protein that is used as a biomarker to follow severity and progression in infectious and inflammatory diseases. Its pathophysiological mechanisms of action are still poorly defined. CRP in its pentameric form exhibits weak anti-inflammatory activity. The monomeric isoform (mCRP) exerts potent proinflammatory properties in chondrocytes, endothelial cells, and leucocytes. No data exist regarding mCRP effects in human intervertebral disc (IVD) cells. This work aimed to verify the pathophysiological relevance of mCRP in the aetiology and/or progression of IVD degeneration.

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Dead-space management, following dead bone resection, is an important element of successful chronic osteomyelitis treatment. This study compared two different biodegradable antibiotic carriers used for dead-space management, and reviewed clinical and radiological outcomes. All cases underwent single-stage surgery and had a minimum one-year follow-up.

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The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI).

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The success rates of two-stage revision arthroplasty for infection have evolved since their early description. The implementation of internationally accepted outcome criteria led to the readjustment of such rates. However, patients who do not undergo reimplantation are usually set aside from these calculations. The aim of this study was to investigate the outcomes of two-stage revision arthroplasty when considering those who do not undergo reimplantation, and to investigate the characteristics of this subgroup.

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With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases.

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Femoral cement-in-cement revision is a well described technique to reduce morbidity and complications in hip revision surgery. Traditional techniques for septic revision of hip arthroplasty necessitate removal of all bone cement from the femur. In our two centres, we have been using a cement-in-cement technique, leaving the distal femoral bone cement in selected patients for septic hip revision surgery, both for single and the first of two-stage revision procedures. A prerequisite for adoption of this technique is that the surgeon considers the cement mantle to be intimately fixed to bone without an intervening membrane between cement and host bone. We aim to report our experience for this technique.

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To explore the effect of different durations of antibiotics after stage II reimplantation on the prognosis of two-stage revision for chronic periprosthetic joint infection (PJI).

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Synovial fluid white blood cell (WBC) count and percentage of polymorphonuclear cells (%PMN) are elevated at periprosthetic joint infection (PJI). Leucocytes produce different interleukins (IL), including IL-6, so we hypothesized that synovial fluid IL-6 could be a more accurate predictor of PJI than synovial fluid WBC count and %PMN. The main aim of our study was to compare the predictive performance of all three diagnostic tests in the detection of PJI.

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Tert-butylhydroquinone (tBHQ) has been identified as an inhibitor of oxidative stress-induced injury and apoptosis in human neural stem cells. However, the role of tBHQ in osteoarthritis (OA) is unclear. This study was carried out to investigate the role of tBHQ in OA.

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Fungal periprosthetic joint infections (fPJIs) are rare complications, constituting only 1% of all PJIs. Neither a uniform definition for fPJI has been established, nor a standardized treatment regimen. Compared to bacterial PJI, there is little evidence for fPJI in the literature with divergent results. Hence, we implemented a novel treatment algorithm based on three-stage revision arthroplasty, with local and systemic antifungal therapy to optimize treatment for fPJI.

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Periprosthetic hip and knee infection remains one of the most severe complications following arthroplasty, with an incidence between 0.5% to 1%. This study compares the outcomes of revision surgery for periprosthetic joint infection (PJI) following hip and knee arthroplasty prior to and after implementation of a specialist PJI multidisciplinary team (MDT).

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Single-stage revision total knee arthroplasty (rTKA) is gaining popularity in treating chronic periprosthetic joint infections (PJIs). We have introduced this approach to our clinical practice and sought to evaluate rates of reinfection and re-revision, along with predictors of failure of both single- and two-stage rTKA for chronic PJI.

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Infection complicating primary total knee arthroplasty (TKA) is a common reason for revision surgery, hospital readmission, patient morbidity, and mortality. Increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) is a particular concern. The use of vancomycin as prophylactic agent alone or in combination with cephalosporin has not demonstrated lower periprosthetic joint infection (PJI) rates, partly due to timing and dosing of intravenous (IV) vancomycin administration, which have proven important factors in effectiveness. This is a retrospective review of a consecutive series of primary TKAs examining incidence of PJI, adverse reactions, and complications using IV versus intraosseous (IO) vancomycin at 30-day, 90-day, and one-year follow-up.

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In contrast to operations performed for other fractures, there is a high incidence rate of surgical site infection (SSI) post-open reduction and internal fixation (ORIF) done for tibial plateau fractures (TPFs). This study investigates the effect of induced membrane technique combined with internal fixation for managing SSI in TPF patients who underwent ORIF.

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The management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is challenging. The correct antibiotic management remains elusive due to differences in epidemiology and resistance between countries, and reports in the literature. Before the efficacy of surgical treatment is investigated, it is crucial to analyze the bacterial strains causing PJI, especially for patients in whom no organisms are grown.