Osteoporosis (OP) and osteoarthritis (OA) are leading causes of musculoskeletal dysfunction in elderly, with chondrocyte senescence, inflammation, oxidative stress, subcellular organelle dysfunction, and genomic instability as prominent features. Age-related intestinal disorders and gut dysbiosis contribute to host tissue inflammation and oxidative stress by affecting host immune responses and cell metabolism. Not surprisingly, the development of OP and OA correlate with dysregulations of the gut microflora in rodents and humans. Intestinal microorganisms produce metabolites, including short-chain fatty acids, bile acids, trimethylamine N-oxide, and liposaccharides, affecting mitochondrial function, metabolism, biogenesis, autophagy, and redox reactions in chondrocytes to regulate joint homeostasis. Modulating the abundance of specific gut bacteria, like Lactobacillus and Bifidobacterium, by probiotics or fecal microbiota transplantation appears to suppress age-induced chronic inflammation and oxidative damage in musculoskeletal tissue and holds potential to slow down OP development. The talk will highlight treatment options with probiotics or metabolites for modulating the progression of OA and OP

An increasing elderly population means joint replacement surgery numbers are projected to increase, with associated complications such as periprosthetic joint infections (PJI) also rising. PJI are particularly challenging due to antimicrobial resistant biofilm development on implant surfaces and surrounding tissues, with treatment typically involving invasive surgeries and systemic antibiotic delivery. Consequently, functionalisation of implant surfaces to prevent biofilm formation is a major research focus. This study characterises clinically relevant antimicrobials including gentamicin, clindamycin, daptomycin, vancomycin and caspofungin within a silica-based, biodegradable sol-gel coating for prosthetic devices. Antimicrobial activity of the coatings against clinically relevant microorganisms was assessed via disc diffusion assays, broth microdilution culture methods and the MBEC assay used to determine anti-biofilm activity. Human and bovine cells were cultured in presence of antimicrobial sol-gel to determine cytotoxicity using Alamar blue and antibiotic release was measured by LC-MS. Biodegradability in physiological conditions was assayed by FT-IR, ICP-MS and measuring mass change. Effect of degradation products on osteogenesis were studied by culturing mesenchymal stem cells in the presence of media in which sol-gel samples had been immersed. Antimicrobial-loaded coatings showed strong activity against a wide range of clinically relevant bacterial and fungal pathogens with no loss of activity from antibiotic alone. The sol-gel coating demonstrated controlled release of antimicrobials and initial sol-gel coatings showed no loss of viability on MSCs with gentamicin containing coatings. Current work is underway investigating cytotoxicity of sol-gel compositions against MG-63 cells and primary osteoblasts. This research forms part of an extended study into a promising antimicrobial delivery strategy to prevent PJI. The implant coating has potential to advance PJI infection prevention, reducing future burden upon healthcare costs and patient wellbeing

Osteomyelitis is an inflammatory condition accompanied by the destruction of bone and caused by an infecting microorganism. Open contaminated fractures can lead to the development of osteomyelitis of the fractured bone in 3-25% of cases, depending on fracture type, degree of soft-tissue injury, degree of microbial contamination, and whether systemic and/or local antimicrobial therapies have been administered. Untreated, infection will ultimately lead to non-union, chronic osteomyelitis, or amputation. We report a case series of 10 patients that presented with post-operative infected non-union of the distal femur with or without prior surgery. The cases were performed at Padmashree Dr. D. Y. Patil Hospital, Nerul, Navi Mumbai, India. All the patients’ consents were taken for the study which was carried out in accordance with the Helsinki Declaration. The methodology involved patients undergoing a two-stage procedure in case of no prior implant or a three-stage procedure in case of a previous implant. Firstly, debridement and implant removal were done. The second was a definitive procedure in form of knee arthrodesis with ring fixator and finally followed by limb lengthening surgery. Arthrodesis was planned in view of infection, non-union, severe arthritic, subluxated knee, stiff knee, non-salvage knee joint, and financial constraints. After all the patients demonstrated wound healing in 3 months along with good radiographic osteogenesis at the knee arthrodesis site, limb lengthening surgeries by tibial osteotomy were done to overcome the limb length discrepancy. Distraction was started and followed up for 5 months. All 10 patients showed results with sound knee arthrodesis and good osteogenesis at the osteotomy site followed by achieving the limb length just 1-inch short from the normal side to achieve ground clearance while walking. Our case series is unique and distinctive as it shows that when patients with infected nonunion of distal femur come with the stiff and non-salvage knee with severe arthritic changes and financial constraints, we should consider knee arthrodesis with Ilizarov ring fixator followed by limb lengthening surgery

Orthopedic Device-Related Infections (ODRIs) are a major medical challenge, particularly due to the involvement of biofilm-encased and multidrug-resistant bacteria. Current treatments, based on antibiotic administration, have proven to be ineffective. Consequently, there is a need for antibiotic-free alternatives. Antimicrobial peptides (AMPs) are a promising solution due to their broad-spectrum of activity, high efficacy at very low concentrations, and low propensity to induce resistance. We aim to develop a new AMP-based chitosan nanogel to be injected during orthopedic device implantation to prevent ODRIs. Chitosan was functionalized with norbornenes (NorChit) through the reaction with carbic anhydride and then, a cysteine-modified AMP, Dhvar5, a peptide with potent antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA), was covalently conjugated to NorChit (NorChit- Dhvar5), through a thiol-norbornene photoclick chemistry (UV= 365 nm). For NorChit-Dhvar5 nanogels production, the NorChit-Dhvar5 solution (0.15% w/v) and Milli-Q water were injected separately into microfluidic system. The nanogels were characterized regarding size, concentration, and shape, using Transmission Electron Microscopy (TEM), Nanoparticle Tracking Analysis (NTA) and Dynamic light scattering (DLS). The nanogels antibacterial properties were assessed in Phosphate Buffer (PBS) for 6 h, against four relevant microorganisms (Pseudomonas aeruginosa, S. aureus and MRSA, and in Muller- Hinton Broth (MHB), 50% (v/v) in PBS, supplemented with human plasma (1% (v/v)), for 6 and 24 h against MRSA. The obtained NorChit-Dhvar5 nanogels, presented a round-shaped and ∼100 nm. NorChit- Dhvar5 nanogels in a concentration of 10. 10. nanogels/mL in PBS were capable of reducing the initial inoculum of P. aeruginosa by 99%, S. aureus by 99%, and MRSA by 90%. These results were corroborated by a 99% MRSA reduction, after 24 h in medium. Furthermore, NorChit-Dhvar5 nanogels do not demonstrate signs of cytotoxicity against MC3T3-E1 cells (a pre-osteoblast cell line) after 14 days, having high potential to prevent antibiotic-resistant infection in the context of ODRIs

Obesity is correlated with the development of osteoporotic diseases. Gut microbiota-derived metabolite trimethylamine-n-oxide (TMAO) accelerates obesity-mediated tissue deterioration. This study was aimed to investigate what role TMAO may play in osteoporosis development during obesity. Mice were fed with high-fat diet (HFD; 60 kcal% fat) or chow diet (CD; 10 kcal% fat) or 0.2% TMAO in drinking water for 6 months. Body adiposis and bone microstructure were investigated using μCT imaging. Gut microbiome and serum metabolome were characterized using 16S rRNA sequencing and liquid chromatography-tandem mass spectrometry. Osteogenic differentiation of bone-marrow mesenchymal cells was quantified using RT-PCR and von Kossa staining. Cellular senescence was evaluated by key senescence markers p16, p21, p53, and senescence association β-galactosidase staining. HFD-fed mice developed hyperglycemia, body adiposis and osteoporosis signs, including low bone mineral density, sparse trabecular microarchitecture, and decreased biomechanical strength. HFD consumption induced gut microbiota dysbiosis, which revealed a high Firmicutes/Bacteroidetes ratio and decreased α-diversity and abundances of beneficial microorganisms Akkermansiaceae, Lactobacillaceae, and Bifidobacteriaceae. Serum metabolome uncovered increased serum L-carnitine and TMAO levels in HFD-fed mice. Of note, transplantation of fecal microbiota from CD-fed mice compromised HFD consumption-induced TMAO overproduction and attenuated loss in bone mass, trabecular microstructure, and bone formation rate. TMAO treatment inhibited trabecular and cortical bone mass and biomechanical characteristics; and repressed osteogenic differentiation capacity of bone-marrow mesenchymal cells. Mechanistically, TMAO accelerated mitochondrial dysfunction and senescence program, interrupted mineralized matrix production in osteoblasts. Gut microbial metabolite TMAO induced osteoblast dysfunction, accelerating the development of obesity-induced skeletal deterioration. This study, for the first time, conveys a productive insight into the catabolic role of gut microflora metabolite TMAO in regulating osteoblast activity and bone tissue integrity during obesity

Introduction. Identification of the causative pathogen in musculoskeletal infection is critical as it directs further treatment. Fracture-related infection is often associated with ‘no growth’ in standard culture. We investigated the efficiency of two alternate methods to identify the causative pathogen, namely extended bacterial culture and 16Sr RNA gene sequence analysis with next generation sequencing (NGS) in ‘culture negative’ fracture related infections. Method. Patients were diagnosed as having fracture related infection based on the MSIS criteria (n=120). All patients had samples taken for culture and sensitivity. All samples which were culture negative by standard culture methods formed the study group. These samples were subjected to further extended culture in both aerobic and anaerobic medium for 14 days to improve recovery of pathogens. Further, DNA isolated from implants from a sub-group of these culture negative patients were subjected to 16SrRNA gene amplification followed by Sanger sequencing. Subsequent sequencing analysis was performed using the Illumina NGS platform which identified and detected the most abundant genera/species present in those samples more precisely. Result. 57 culture negative samples formed the study group. Eight samples (14%) converted to positivity after 14 days of culture. Bacteroides fragilis was the commonest yield. 14 samples underwent 16SrRNA gene amplification followed by Sanger sequencing. Acinetobacter baumannii, Enterococcus faecalis, Pseudomonas aeruginosa were identified as common pathogens. Next generation sequencing (n=12) not only identified common pathogens like as Staphylococcus, Acinetobacter baumannii, but also many uncultivable species. Conclusion. Positive results from extended bacterial culture are about 15%. The delay in definite identification of pathogens in extended culture may be critical in certain clinical situations. Molecular methods are quicker and have additional yield in culture negative infections. The exact role of all microorganisms identified by molecular methods in the pathogenesis of infection is unknown

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

Over the last decades, biodegradable metals emerged as promising materials for various biomedical implant applications, aiming to reduce the use of permanent metallic implants and, therefore, to avoid additional surgeries for implant removal. However, among the important issue to be solved is their fast corrosion - too high to match the healing rate of the bone tissue. The most effective way to improve this characteristic is to coat biodegradable metals with substituted calcium phosphates. Tricalcium phosphate (β-TCP) is a resorbable bioceramic widely used as synthetic bone graft. In order to modulate and enhance its biological performance, the substitution of Ca2+ by various metal ions, such as strontium (Sr2+), magnesium (Mg2+), iron (Fe2+) etc., can be carried out. Among them, copper (Cu2+), manganese (Mn2+), zinc (Zn2+) etc. could add antimicrobial properties against implant-related infections. Double substitutions of TCP containing couples of Cu2+/Sr2+ or Mn2+/Sr2+ ions are considered to be the most perspective based on the results of our study. We established that single phase Ca3−2x(MˊMˊˊ)x(PO4)2 solid solutions are formed only at x ≤ 0.286, where Mˊ and Mˊˊ—divalent metal ions, such as Zn2+, Mg2+, Cu2+, Mn2+, and that in case of double substitutions, the incorporation of Sr2+ ions allows one to extend the limit of solid solution due to the enlargement of the unit cell structure. We also reported that antimicrobial properties depend on the substitution ion occupation of Ca2+ crystal sites in the β-TCP structure. The combination of two different ions in the Ca5 position, on one side, and in the Ca1, Ca2, Ca3, and Ca4 positions, on another side, significantly boosts antimicrobial properties. In the present work, zinc-lithium (Zn-Li) biodegradable alloys were coated with double substituted Mn2+/Sr2+ β-TCP and double substituted Cu2+/ Sr2+ β-TCP, with the scope to promote osteoinductive effect (due to the Sr2+ presence) and to impart antimicrobial properties (thanks to Cu2+ or Mn2+ ions). The Pulsed Laser Deposition (PLD) method was applied as the coating's preparation technique. It was shown that films deposited using PLD present good adhesion strength and hardness and are characterized by a nanostructured background with random microparticles on the surface. For coatings characterization, Fourier Transform Infrared Spectroscopy, X-ray Diffraction, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray and X-ray Photoelectron Spectroscopy were applied. The microbiology tests on the prepared coated Zn-Li alloys were performed with the Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Salmonella typhimurium, Escherichia coli) bacteria strains and Candida albicans fungus. The antimicrobial activity tests showed that Mn2+/Sr2+ β-TCP -coated and Cu2+/Sr2+ β-TCP coated Zn-Li alloys were able to inhibit the growth of all five microorganisms. The prepared coatings are promising in improving the degradation behavior and biological properties of Zn-Li alloys, and further studies are necessary before a possible clinical translation

The main problem of infected orthopaedic implants is that the presence of microorganisms in an organized biofilm making them difficult accessible for antibiotics. This biofilm consists of a complex community of microorganisms embedded in an extracellular matrix that forms on surfaces such as an implant. Non-contact induction heating uses pulsed electromagnetic fields to induce so-called ‘eddy currents’ within metal objects which causes them to heat up. This heat causes thermal damage to the bacterial biofilm hence killing the bacteria on the metal implant. The purpose of this study is to determine the effectiveness of induction heating on killing Staphylococcus epidermidis in a biofilm. S. epidermidis biofilms were grown on Titanium alloy (Ti6Al4V) coupons and subsequently were heated with a custom-built induction heater to temperatures of 60°C, 70°C, 80°C and 90°C for 3.5 minutes. Temperature was controlled with an infra-red thermal sensor and micro-controller. We also included two control conditions without induction heating: C1 without induction heating and C2 with chlorhexidine 0.5% in 70% alcohol without induction heating. Experiments were repeated 5 times. In the C1 group (no induction heating), 1.3 * 10(7) colony forming units (CFU)/cm(−2) of S. epidermidis were observed. For 60°C, 70C, 80 C and 90C, a 3.9-log reduction, 5.3-log reduction, 5.5-log reduction and 6.1-log reduction in CFU/cm(−2) were observed, respectively. For the C2 (chlorhexidine) there was a 6.7-log reduction CFU/cm(-2). We concluded that induction heating of Titanium coupons is effective in reducing bacterial load in vitro for S. epidermidis biofilms

Ruling out an infection in one-stage knee and hip revisions for presumed aseptic failure by conventional tissue cultures takes up to 14 days. Multiplex polymerase chain reaction (PCR) is a quick test (4–5 hours) for detecting infections. The purpose of this study was to evaluate the negative predictive value of an automated multiplex PCR for the detection of microorganisms in synovial fluid obtained intraoperatively in unsuspected knee and hip revisions. The NPV of the multiplex PCR U-ITI system of synovial fluid compared to tissue cultures of knee and hip revisions was 95.7% and 92.5%, respectively. Cultures required several days for growth whereas the automated mPCR U-ITI system provided results within five hours. The multiplex PCR U-ITI system is a quick and reliable test in ruling out infection in presumed aseptic knee and hip revisions. With this test the number of unsuspected infected revisions can be lowered and antibiotic overtreatment as well as undertreatment after one-stage revision arthroplasty can be avoided. This directly results in a reduction in length of hospital stay, hospital costs and possible antibiotic resistance development

Mesenchymal stromal cells (MSCs) have been one of the most widely studied cell types in preclinical and clinical trials, due to their self-renewing, multipotent capacity, immunomodulatory properties and relative ease of isolation from multiple tissues. Despite limitations and safety concerns, fetal bovine serum (FBS) is still predominantly used for MSC expansion in clinical protocols. In addition, the undefined nature of serum composition and lot-to-lot variability have been linked to reduced reproducibility and efficiency of MSC bioprocessing. Moreover, use of animal serum in human cell culture increases the risk of contamination with adventitious pathogenic microorganisms, such as viruses, prions and bacteria. Hence, a defined serum-free formulation can provide increased safety, better control over physiological responsiveness, consistent performance and reproducible results. Here we present preliminary data on a prototype serum-free medium optimized for in vitro tenogenic differentiation of human bone marrow-derived MSCs. This serum-free formulation is capable of generating tenocyte-like cells in vitro expressing tenogenic markers such as Scx, Tnmd, TnC, Collagen I and Collagen III, whilst repressing expression of specific markers of other mesenchymal lineages

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

Infected wounds are a major problem for patients and health care systems. The inflammation triggers expression of high levels of extracellular protease activities which degrade newly formed granulation tissue. The expression of host-derived proteases had been studied in wound healing extensively. In contrast, the contribution of bacterial proteases in impaired healing acute and chronic wounds is poorly understood as is how bacterial proteases can be blocked. In this study the expression of P. aeruginosa proteases was studied. P. aeruginosa is associated with poor healing and sufficiently common in wound infections to merit closer study. We used in vitro biofilm and planktonic culture models to analyze the culture-dependent expression of different P. aeruginosa proteases and how protease modulating polymers can inhibit activities. P. aeruginosa (PAO1, DSM 22644) was grown in LB. o. medium (aerated planktonic cultures) or in a biofilm culture model (dialysis tubing on LB. o. plates). The supernatant of planktonic or wash fluids from biofilm cultures were analyzed for protease activity. Global extracellular protease activities increased in a time- and culture condition-dependent manner (for planktonic cultures 180 ng/ml trypsin equivalent 8h, 330 ng/ml 24h, 490 ng/ml 48h; biofilm cultures 190 ng/ml trypsin equivalent 8h, 420 ng/ml 24h, 170 ng/ml 48h). Enzyme zymography revealed in biofilm cultures predominant bands at 50 kD (8h, 24h, 48h), 90 kD (24h) and > 200 kD (8h, 24h, 48h). In planktonic cultures the pattern was different 50 kD (8h), 90 kD (8h, 24h, 48h), 130 kD (24h, 48h) and > 200 kD (8h, 24h). Two different polyacrylate superabsorbers could inhibit P. aeruginosa protease activities. Favor PAC 300 blocked protease activity by 60% and SXM 9170 by 35%. These data demonstrate complex, culture-dependent expression of extracellular proteases in P. aeruginosa, a microorganism associated with poor wound healing outcomes. From a therapeutic perspective polyacrylate superabsorbers strongly inhibited global protease activities. In the next steps the protease expression pattern needs to be analyzed in P. aeruginosa wounds and correlated with healing progression

Adhered bacteria on titanium surfaces are able to decrease its corrosion potential and impedance values at the lowest frequencies. This result points to the detrimental influence of the biofilm on the passive film formed on the surfaces, independently on the surface finishes. Titanium is one of the most used metallic biomaterials for biological and implant applications. The spontaneous formation of a protective passive film around 2–5 nm thick, make titanium unique as a biomaterial for implants. Its composition has been described by a three-layer model: TiO2/Ti2O3/TiO and its stability is ultimately responsible for the success of osseointegrated titanium implants. The cases of breakdown of the protective passive film are associated with highly acidic environments induced by bacterial biofilms and/or inflammatory processes that lead to localized corrosion of titanium and, in extreme cases, implant failure. Bearing in mind that the surface design of a titanium implant is a key element involved in the healing mechanisms at the bone-implant interface, the surface modifications have sought to enhance the biomechanical anchorage of the implant and promote osseointegration at the cell-biomolecular level. However, little attention has been paid to the effects of these surface modifications in the microbiologically induced corrosion (MIC). The aim of this work is to evaluate the potential for MIC of titanium in the short term under viable bacterial cells of Streptococcus mutansas a representative microorganism of oral biofilm considered to be a highly cariogenic pathogen. Discs of 64 mm. 2. surface area of commercially pure titanium, grade 4, were supplied by Biotechnology Institute (BTI, Vitoria, Spain). Four surface treatments were studied: two acid etchings (low roughness, opN and high roughness, opV). In addition, acid etched plus anodic oxidation (opNT). For comparative purposes, two surface finishes have been included: high roughness – corresponding with sandblasting-large grit plus acid (SLA); and, as-machined titanium (mach). The oral strain used for assessing the biofilm formation on the corrosion behavior of Ti surfaces was Streptococus mutansATCC 25175, obtained from the Spanish Type Culture Collection (CECT). The study of MIC from Streptococcus mutanson surfaces of Ti was carried out in an electrochemical cell specifically designed and patented by some of the present authors [1]. A three set up configuration of the electrochemical cell was used in the experiments. The measurement of the corrosion potential and electrochemical impedance was performed at different periods of incubation of bacteria: 2, 7, 15, 21 and 28 days. Out Slight but continuous decrease in the corrosion potential and impedance values at the lowest frequencies indicate the deleterious influence of the biofilm on the passive film formed on the surfaces, independently on the surface finishes. This research suggests that the most appropriate surface modification for the dental implant portion at the bone level would be the acid etched of high roughness (opV) surface

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

Objectives

Vancomycin and fosfomycin are antibiotics commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA) infection. This study compares the in vitro inhibitory effects against MRSA of articulating cement spacers impregnated with either vancomycin or fosfomycin.

The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed.

In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups.

After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate.

Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes.

Cite this article: Bone Joint J 2014; 96-B:845–50.

Platelet-leucocyte gel (PLG), a new biotechnological blood product, has hitherto been used primarily to treat chronic ulcers and to promote soft-tissue and bone regeneration in a wide range of medical fields. In this study, the antimicrobial efficacy of PLG against Staphylococcus aureus (ATCC 25923) was investigated in a rabbit model of osteomyelitis. Autologous PLG was injected into the tibial canal after inoculation with Staph. aureus. The prophylactic efficacy of PLG was evaluated by microbiological, radiological and histological examination. Animal groups included a treatment group that received systemic cefazolin and a control group that received no treatment.

Treatment with PLG or cefazolin significantly reduced radiological and histological severity scores compared to the control group. This result was confirmed by a significant reduction in the infection rate and the number of viable bacteria. Although not comparable to cefazolin, PLG exhibited antimicrobial efficacy in vivo and therefore represents a novel strategy to prevent bone infection in humans.