Aims. 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. Methods. S. aureus-Xen36 biofilms were grown on the various substrates for 24 hours or seven days.
Aims. This study investigated vancomycin-microbubbles (Vm-MBs) and meropenem (Mp)-MBs with ultrasound-targeted microbubble destruction (UTMD) to disrupt biofilms and improve bactericidal efficiency, providing a new and promising strategy for the treatment of device-related infections (DRIs). Methods. A film hydration method was used to prepare Vm-MBs and Mp-MBs and examine their characterization.
Aim. “Implant associated Staphylococcus aureus or S. epidermidis infections are often difficult to treat due to the formation of biofilms on prosthetic material.
Aim. Rifampicin plays an important role in the treatment of staphylococcal prosthetic joint infection, as rifampicin-containing combinations have shown a high efficacy against S. aureus biofilm infections. However, the emergence of rifampin-resistant strains is a feared complication and the use of rifampicin in those cases seems unwarranted. Therefore, we evaluated the activity of bacteriophage Sb1 in combination with different antibiotics against the biofilm of four rifampicin-resistant MRSA strains as alternative therapeutic approach. Method. Four rifampicin-resistant MRSA strains were used in this study. The MIC for all tested antibiotics was determined by Etest.
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. Method. E. coli ATCC 25922, P. aeruginosa ATCC 27853 and 15 clinical isolates were used for this study. MIC values were determined by Etest.
Biofilm formation (BF) in wounds and on biomaterials is a severe complication in trauma and orthopaedic surgery. Maggot therapy is successfully applied in wounds, that are suspected for BF. This study investigated BF by Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella oxytoca, Enterococcus faecalis and Enterobacter cloacae on polyethylene, titanium and stainless steel and tested the effect on BF by maggot excretions/secretions (ES). Comb-forming models of the biomaterials were made to fit into a 96-well microtiter plate. In the wells, a suspension of 2.5 x 105 bacteria/ml and nutrient medium was pipetted. Combs were placed in the wells and incubated for 3, 5, 7, and 9 days at 37°C. The formed biofilms were stained in crystal-violet and eluted in ethanol. The optical density (OD 595 nm) was measured to quantify BF. Then, maggots excretions/secretions (ES) were collected according to a standardized method, added in different concentrations to (non-stained) mature biofilms (7 days), incubated another 24 hours and at last stained and measured. The results showed biofilm reduction by ES on all biomaterials.
The aim of the present study was to assess the antibiofilm activity of daptomycin- and vancomycin-loaded poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL100 (EUD) microparticles against mature biofilms of polysaccharide intercellular adhesin-positive S. epidermidis. The effect of plain, daptomycin- and vancomycin-loaded PMMA and PMMA-EUD microparticles on S. epidermidis biofilms was assessed by isothermal microcalorimetry (IMC) and fluorescence in situ hybridization (FISH).
The December 2022 Research Roundup360 looks at: Halicin is effective against
Aim
Method
Using a methicillin-sensitive Abstract
OBJECTIVES
METHODS
Staphylococcus aureus is responsible for 60–70% infections of surgical implants and prostheses in Orthopaedic surgery, with cumulative treatment costs for all prosthetic joint infections estimated to be ∼ $1 billion per annum (UK and North America). Its ability to develop resistance or tolerance to a diverse range of antimicrobial compounds, threatens to halt routine elective implant surgery. One strategy to overcome this problem is to look beyond traditional antimicrobial drug therapies and investigate other treatment modalities. Biophysical modalities, such as ultrasound, are poorly explored, but preliminary work has shown potential benefit, especially when combined with existing antibiotics. Low intensity pulsed ultrasound is already licensed for clinical use in fracture management and thus could be translated quickly into a clinical treatment Using a methicillin-sensitive S. aureus reference strain and the dissolvable bead assay, biofilms were challenged with gentamicin +/− low-intensity ultrasound (1.5MHz, 30mW/cm2, pulse duration 200µs/1KHz) for 180 minutes and 20 minutes, respectively. The primary outcome measures were colony-forming units/mL (CFU/mL) and the minimum biofilm eradication concentration (MBEC) of gentamicin. The mean number of S. aureus within control biofilms was 1.04 × 109 CFU/mL. Assessment of cellular metabolism was conducted using a liquid-chromatography-mass spectrometry, as well as a triphenyltetrazolium chloride assay coupled with spectrophotometry. There was no clinically or statistically significant (p=0.531) reduction in viable S. aureus following ultrasound therapy alone. The MBEC of gentamicin for this S. aureus strain was 256 mg/L. The MBEC of gentamicin with the addition of ultrasound was reduced to 64mg/L. Metabolic activity of biofilm-associated S. aureus was increased by 25% following ultrasound therapy (p < 0 .0001), with identification of key biosynthetic pathways activated by non-lethal dispersal. Low intensity pulsed ultrasound was associated with a four-fold reduction in the effective biofilm eradication concentration of gentamicin, bringing the MBEC of gentamicin to within clinically achievable concentrations. The mechanism of action was due to partial disruption of the extracellular matrix which led to an increase of nutrient availability and oxygen tension within the biofilm. This metabolic stimulus was responsible for the reversal of gentamicin tolerance in the biofilm-associated S. aureus.
Staphylococcus aureus is responsible for 60–70% infections of surgical implants and prostheses in Orthopaedic surgery, costing the NHS £120–200 million per annum. Its ability to develop tolerance to a diverse range of antimicrobial compounds, threatens to halt routine elective implant surgery. One strategy to overcome this problem is to look beyond traditional antimicrobial drug therapies and investigate other treatment modalities. Biophysical modalities, such as ultrasound, are poorly explores, but preliminary work has shown potential benefit, especially when combined with existing antibiotics. Using a methicillin-sensitive S. aureus reference strain and the dissolvable bead assay, bacterial biofilms were challenged by gentamicin +/− low-intensity ultrasound (1.5MHz, 30W/cm2, pulse duration 200µs/1KHz) for 20 minutes. The outcome measures were colony-forming units/mL (CFU/mL) and the minimum biofilm eradication concentration (MBEC) of gentamicin. The mean number of S. aureus within control biofilms was 1.04 × 109 CFU/mL. There was no clinically or statistically significant (p=0.531) reduction in viable S. aureus following ultrasound therapy alone. The MBEC of gentamicin for this S. aureus strain was 256 mg/L. The MBEC of gentamicin with the addition of ultrasound was 64mg/L. Low intensity pulsed ultrasound was associated with a four-fold reduction in the effective biofilm eradication concentration of gentamicin; bringing the MBEC of gentamicin to within clinically achievable concentrations
Staphylococcus aureus is responsible for 60–70% infections of surgical implants and prostheses in Orthopaedic surgery, costing the NHS £120–200 million per annum. Its ability to develop resistance or tolerance to a diverse range of antimicrobial compounds, threatens to halt routine elective implant surgery. One strategy to overcome this problem is to look beyond traditional antimicrobial drug therapies and investigate other treatment modalities. Biophysical modalities, such as ultrasound, are poorly explored, but preliminary work has shown potential benefit, especially when combined with existing antibiotics. Using a methicillin-sensitive S. aureus reference strain and the dissolvable bead assay, biofilms were challenged by a low-intensity ultrasound (1.5MHz, 30mW/cm2, pulse duration 200µs/1KHz) for 20 minutes and gentamicin. The outcome measures were colony-forming units/mL (CFU/mL) and the minimum biofilm eradication concentration (MBEC) of gentamicin. The mean number of S. aureus within control biofilms was 1.04 × 109 CFU/mL. There was no clinically or statistically significant (p=0.531) reduction in viable S. aureus following ultrasound therapy alone. The MBEC of gentamicin for this S. aureus strain was 256 mg/L. The MBEC of gentamicin with the addition of ultrasound was 64mg/L. Further studies confirmed that the mechanism of action was due to incomplete disruption of the extracellular matrix with subsequent metabolic stimulation of the dormant biofilm-associated bacteria due to increased nutrient availability and oxygen tension. Low intensity pulsed ultrasound was associated with a 4-fold reduction in the effective biofilm eradication concentration of gentamicin; bringing the MBEC of gentamicin to within clinically achievable concentrations.
Prosthetic joint infection (PJI) remains the most severe complication of arthroplasty. Failure of intensive, long-term antibiotic treatment for PJI often requires removal of the implant. Antibiotic failure is thought to be caused by biofilm and persister formation. Novel anti-biofilm and anti-persister strategies are urgently needed. Here, we investigated the effects of several antimicrobial peptides on the bacteria within antibiotic-treated biofilms in an On polystyrene, a mature (7 day-old) methicillin-resistant Aims
Methods
Irrigation is a major step during debridement surgery in the context of Prosthetic Joint Infections (PJI), but its effects on biofilms are poorly described. The present study aims at evaluating the effect of PW alone or followed by antibiotics on MSSA and MRSA biofilms grown on Ti6Al4V coupons in-vitro. Strains: 1 reference (MSSA: ATCC25923; MRSA: ATCC33591) and 2 clinical MSSA and MRSA isolated from PJI. Biofilm culture: Coupons were incubated for 24h at 37°C with bacteria (starting inoculum ∼6.6Log10CFU/mL in TGN [TSB + 1% glucose + 2% NaCl]), under shaking at 50rpm. Treatment: Half of the coupons were irrigated with 50mL physiological serum from 5cm using a Stryker Interpulse; the coupons were then either analysed (ControlT0 and PWT0) or reincubated for 24h in TGN or TGN containing flucloxacillin (MSSA) or vancomycin (MRSA) at MIC or 20mg/L. Analysis: Coupons were rinsed twice with PBS. Biomass was measured by crystal violet (CV) assay. CFUs were counted after recovering bacteria from coupons using sonication and TSA plating.Aim
Method
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 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 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.
Peri-prosthetic joint infection (PJI) is one the most devastating complications of joint arthroplasty. Although PJI is an infrequent complication (the reported incidence is 1%-2% in the United States), it is the most common indication for revision total knee arthroplasty in the Medicare population and the third most frequent indication for revision total hip arthroplasty. Moreover, the prevalence of PJI appears to be on the rise, with a projected number exceeding 60,000 to 70,000 cases in the United States by 2020. It is estimated that more than 25% of revision procedures annually are attributed to PJI and this number is expected to increase in the upcoming years. The increase in the prevalence of obesity, diabetes, and other comorbidities among the patient population and the emergence of resistant infecting organisms are some of the reasons for the expected rise in the number of infections that medical community will witness. The challenges that PJI present to the orthopaedic community are on many fronts. Prevention of PJI has proven to be a difficult task indeed. Effective strategies for prevention of PJI are being refined. The Center for Disease Control will be publishing its updated Surgical Site Prevention Guidelines in the next few months that consists of specific recommendations for prevention of PJI. In recent years, strides are made in introducing novel molecular techniques for diagnosis of PJI, which may stand to change our practices. The current surgical technique for management of PJI, besides the immense cost, fall short of delivering high success to the patients. The major problem in eradication of infection relates to formation of biofilm on the implant surface and internalization of the organisms by affected cells. Biofilm is a sophisticated structure comprising of organisms embedded in multiple layers of glycoccalyx that allows the organisms to evade host immunity and is impenetrable to antibiotics. These organisms are capable of communicating through molecular mechanisms such as quorum sensing that affords them advantage for survival in the host environment. In recent years strategies to prevent colonization of the implant surface, an essential first step in formation of biofilm, or biofilm disruption techniques have been introduced. A recent International Consensus meeting on PJI that assembled more than 350 experts identified some of the best practices in this field and identified areas in need of future research. Moving into the future, the field of orthopaedics in general and PJI in particular stand to benefit from the discoveries in the field of molecular diagnostics, metabolomics and epigenetics.
Determine the time concentration profile required to achieve vancomycin-mediated eradication of Mature Aim
Method
Cement is still in common usage in primary and revision arthroplasty surgery. Infection rates in cemented arthroplasties ranges from 1–4% and poses a huge problem for the revision arthroplasty surgeon. Infection in septic implants is biofilm based and almost completely resistant to conventional anti-microbial therapy. Recent papers have questioned the efficacy of using gentamicin-loaded cement in arthroplasty as staphylococcus aureus biofilms will develop on same. The focus of this study was to investigate the efficacy of antibiotic loaded cement in preventing initial bacterial adhesion and subsequent development of a bacterial biofilm in vitro. Three cements Simplex unloaded, Simplex with erythromycin and Simplex with tobramycin were mixed in a conventional manner, ie vacuum hand mixing in sterile conditions and then injected into pre-moulded PTFE coated cylinder moulds yielding 8 cylinders in each group. The cement cylinders were then removed and exposed to a known pathogenic strain of staphylococcus aureus ATCC—29213-NCTC 12973 in solution 3x106 Colony forming units CFH/ml) for 15 minutes. The cylinders were then removed and cultured for 24 hours at 37°C in RPMI with Glutamine. Cylinders were then removed and subjected to rinsing in PBS to remove any non-adherent bacteria. Cylinders were then sonicated at 50 Hz in Ringer’s solution and adherent biofilms were serially log diluted and plated on Columbia blood agar. Colonies were counted manually. Control cylinders of unloaded cement showed 120,000 CFU/cm2 of adherent bacteria whereas loaded cement erythromycin and tobramycin showed 500 and 80 CFU/cm2 respectively (p<
.0005 Student t-test). This study shows that loaded cement does not prevent biofilm adhesion in its initial reversible stages whereas unloaded cement does not. This is important since most infected implants are infected at time of primary operation and cements anti-bacterial role beyond the first 48 hours remains questionable, when inflammatory encapsulation of the implant begins. We would therefore question the usage of unloaded cement in primary arthroplasty surgery.
Post-operative surgical site infection following total joint arthroplasty occurs at rates between ~ 0.2–5 %, depending on the joint and the surgeon volume, as well as various patient risk factors. Given that an estimated over 700,000 knee and hip arthroplasties are performed in the US each year this translates to thousands of patients that are affected by this serious, costly and traumatic complication. In addition, it is now recognized that clinical culturing underestimates the infection rate and that a number of aseptic loosenings might actually have an infectious etiology. We have used a combination of non-culture based molecular methods to detect bacteria associated with hardware, antimicrobial impregnated cement, reactive tissue and pus collected during revision surgery in a total elbow arthroplasty (TEA) case and a total ankle revision (TAR) case. Confocal microscopy showed live cocci in biofilm cell clusters, and fluorescent in situ hybridization (FISH) demonstrated S. aureus biofilms. Reverse transcriptase (RT)-PCR, and multiplex PCR coupled with electrospray-ionization mass spectrometry (Ibis T5000) to identify S. aureus, S. epidermidis and genes for methicillin resistance. Together our complimentary techniques comprise compelling evidence that viable biofilm bacteria played an important role in the refractory infections in these cases.
Combination of antibiotics with N-acetylcisteine and sub-MIC concentration of erythromycin was evaluated in two collection and 16 clinical strains of staphylococci isolated from PJI. The results were strain-dependent, so it evidences the necessity of perform individual studies of biofilm susceptibility. Staphylococci are the most common cause of prosthetic joint infections (PJI) (1), making the treatment of this disease difficult due to the increased resistance to antibiotics of biofilms. Combination between antibiotics and other compounds could be a good alternative. The aim of this study was to evaluate the effect of the combination of two compounds with nine antibiotics in biofilms formed by staphylococcal strains isolated from PJI.Summary Statement
Objectives
P.aeruginosa causes acute and chronic-destructive infections, particularly wound infections, or device-associated infections by colonising respiratory tubes, catheters, or implants. The pathogenicity of P.aeruginosa is largely attributed to the relative resistance towards host defence. Especially when organised as biofilms, the bacteria evade phagocytosis and killing by polymorphonuclear neutrophils (PMN). To elucidate the evasion mechanisms, the migration of PMN towards and through P.aeruginosa biofilms was studied. Migration of PMN towards P.aeruginosa biofilms was tested using various in vitro techniques. We found that PMN migrated towards developing P.aeruginosa biofilms, attracted by the quorum-sensing molecule N-3-oxododecanoyl homoserine lactone (3OC12-HSL). Mature biofilms which no longer produced 3OC12-HSL did not attract PMN. Addition of interleukin 8, a potent chemokine, restored the migratory capacity. Once arrived at the biofilms, PMN readily attached with no important difference between developing and mature biofilms. Migration into and penetration of the films, however, was only seen with developing films. By mass spectroscopy it became obvious that a major difference between developing and mature biofilms was the composition of the extracellular polymer substance, of which alginate is a prominent component. A series of experiments with isolated alginate showed that PMN did not migrate on or into alginate-containing matrices, but remained affixed at the contact site just as they did on mature biofilms. The mechanism of this firm attachment is still under investigation; prominent up-regulation of various adhesion molecules was seen, which could provide possible explanation. Mature biofilms, most probably due to the composition of the extracellular polymer substance, do not allow the penetration of PMN. Consequently, bacteria embedded in deeper layers of the biofilm are protected against the host response. Due to the restricted movement of PMN, the bactericidal activity of PMN is only efficient against bacteria in the immediate vicinity, explaining the inefficient host defence.
using a questionnaire to investigate course of disease and health-related quality of life (VAS). 7 patients were treated with and 17 patients without additional application of antibiotics penetrating bacterial biofilms.
In the group of patients treated with additional application of antibiotics penetrating bacterial biofilms 6 of 7 (86%) implants were salvaged and reduced number of revison surgery was needed.
Due to the fact that revision arthroplasty is often associated with limited function after infection of total knee joint, retention of the implant has to be considered a therapeutic alternative in early infection.
The formation of bacterial biofilms is increasingly recognised as the leading cause of chronic infections. It limits the application of implant materials including catheters, heart valves, or orthopaedic prostheses. It is generally assumed that the infection persists because bacteria organised as biofilms escape the host defence mechanisms. Nevertheless, when studying patients with infected implants, we found a massive infiltration of leukocytes particularly polymorphonuclear neutrophils, PMN, into the site of infection, which led to the question, whether the PMN interact with the bacterial biofilm or not. The interaction of human PMN with Staphylococcus aureus biofilms was studied in vitro. S.aureus was cultivated on glass cover slips for various times under conditions allowing formation of biofilms. Adherence of PMN to biofilms and phagocytosis of the bacteria were observed by confocal laser scan microscopy and time lapse video microscopy. Migration of PMN on and into the biofilm was identified as being phagocytosis, apparent as uptake of bacteria into the cell. Concominantly, in the wake of migrating PMN bacteria depleted zones appeared, which increased in size with time. In addition to phagocytosis, release from PMN of DNA and also of elastase was seen, suggesting the formation of neutrophil extracellular traps (NETs). So far, the signal for DNA release and NET formation has not been identified; of note is, however, that they occurred preferentially on established “old” biofilms and in the absence of the opsonising human serum, while phagocytosis was most efficient with developing “young” biofilms. Taken together, our data provide evidence that bacteria in biofilms are not entirely protected against host defence but that phagocytosis is still possible, especially when the biofilm is opsonised with human serum. Whether NET formation also contributes to bacteria killing in biofilms cannot be decided as yet but remains an attractive alternative.
Aim. Bacteriophages are remerging as alternative and adjunctive therapy for fracture-related infection (FRI). However, current administration protocols involve prolonged retention of a percutaneous draining tube with potential risk of developing superinfection. In this study, we applied a cocktail of in vitro evolved biofilm-targeting phages for Methicillin-resistant Staphylococcus aureus (MRSA) in a hydrogel platform co-delivering vancomycin. In vitro synergy and antibiofilm activity was assessed and a subsequent in vivo study was performed in a mouse FRI model with MRSA. Method. Two evolved bacteriophages (MRSA-R14 and COL-R23) with improved antibiofilm activity against a clinical isolate (MRSA3) were tested in combination with vancomycin and a carboxymethylcellulose (CMC) hydrogel in vitro and in vivo. MRSA3 bacterial biofilms were formed on sterile 4 mm sintered porous glass beads at 37 °C for 24 h.
The October 2015 Research Roundup360 looks at: Wasted implants;
Aims. Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. Methods. Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 10. 6. or 43.0 (SD 8.4) x 10. 5. colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 10. 6. or 72.0 (SD 4.2) x 10. 5. CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting. Results.
One of the most common bacteria in orthopaedic prosthetic infections is Staphylococcus Aureus. Infection causes implant failure due to biofilm production.
The most common bacteria in orthopaedic prosthetic infections are Staphylococcus, namely Staphylococcus Epidermidis (SE) and Staphylococcus Aureus (SA). Infection causes implant failure due to biofilm production.
Introduction. Despite the routine use of irrigation, debridement and systemic antibiotics, there is a high incidence of infection in severe open fractures. The synergistic use of local and systemic antibiotics appreciably reduces infection rates although the time window within which this is effective is unknown. The aim was to determine if delaying treatment of wounds causes higher levels of infection. Methods. A defect was created in the femurs of 90 Sprague-Dawley rats and inoculated with 105CFUs Staphylococcus aureus. At 2, 6 and 24 hours following contamination, the defect was irrigated and debrided. The experimental groups had either vancomycin or tobramycin impregnated PMMA beads placed within the segmental defect. The controls received no further treatment. Two weeks after wound closure, the bacteria within the femur were quantified. Results. Delaying irrigation and debridement resulted in significantly more bacteria (p<0.01) within the control group (2 hr < 6 hr <24 hr). Both locally delivered tobramycin and vancomycin significantly reduced the bacteria (p<0.05) when administered at the earlier time points (2 and 6 hours). Locally-delivered antibiotics were ineffective when delivered at 24 hours. Conclusion. Delaying treatment of contaminated defects reduces its effectiveness to eradicate infection. This is presumably because of the biofilm formation by the bacteria.
Aims. Infections of bone usually require multiple surgery and prolonged periods of treatment. One reason for problems is found in the presence of stationary phase bacteria embedded in biofilms that show increased resistance against conventional antibiotic therapy (up to 1000x MIC).
Periprosthetic joint infections (PJIs) are among the most devastating complications after joint arthroplasty. There is limited evidence on the efficacy of different antiseptic solutions on reducing biofilm burden. The purpose of the present study was to test the efficacy of different antiseptic solutions against clinically relevant microorganisms in biofilm. We conducted an in vitro study examining the efficacy of several antiseptic solutions against clinically relevant microorganisms. We tested antiseptic irrigants against nascent (four-hour) and mature (three-day) single-species biofilm created in vitro using a drip-flow reactor model.Aims
Methods
Metallic implants are used frequently in the operative repair of joints and fractures in orthopaedic surgery. Orthopaedic implant infection is chronic and biofilm based. Present treatment focuses on removing the infective substratum and implant surgically as well as prolonged anti-microbial therapy.
Metallic implants are used frequently in the operative repair of joints and fractures in orthopaedic surgery. Metal infection is a catastrophic complication of the surgery with patients loosing their newfound mobility and independence, associated morbidity and mortality is high. Orthopaedic implant infection is chronic and biofilm based. Present treatment focuses on removing the infective substratum and implant surgically as well as prolonged anti-microbial therapy.
The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Aims
Methods
Introduction: External fixation is used widely in the management of fractures, despite a relatively high incidence of complication, arising from pin loosening and infection. Diamond like carbon (DLC) is a low surface energy coating that can be applied to external fixator pins and may reduce biofilm formation and infection resulting in a lower incidence of pin loosening. Hydroxyapatite (HA) is well established as a coating to enhance fixation of external fixator pins. This study tests the hypothesis that HA and DLC coatings on stainless steel (SS) external fixator pin shafts modify integration of the implant with soft/hard tissues. Materials and Methods: An Orthofix external fixator was used to stabilise a tibial osteotomy with 6 self-drilling/tapping 6mm pins in 32 skeletally mature Friesland ewes. Animals were divided into four groups; SS, DLC, HA partially coated (threads only) and HA fully coated (threads and pin shaft). Pin insertion torque was measured using a torque wrench and extraction torque similarly obtained at 10 weeks when animals underwent euthanasia. Pin performance indices (PPI) were calculated as a ratio of extraction to insertion torque x100%. Pin site 2 was preserved for hard grade resin histology and subsequent pin tissue integration analysis. Pin site 3 was used for analysis of the soft tissue pin shaft interface using transmission electron microscopy. Pin site 5 was examined for the presence of biofilm formation using scanning electron microscopy. Pin site 6 was swabbed for microbiological analysis. Results: SS and DLC pins achieved significantly higher insertion torques compared to HA partially coated pins (p=0.001, 0.002). Both groups of HA coated pins demonstrated a significantly higher, extraction torque and therefore PPI for all pin site positions compared to SS and DLC (p<
0.001– 0.025). The epithelium was found not to be in contact with the pin shaft in all cases. No significant differences were found between the different pin groups for epidermal down growth and dermal contact. Both groups of HA coated pins showed a significantly higher percentage of new bone in direct contact with the embedded threads compared to SS and DLC pins (p<
0.001, p=0.004). The proportion of soft tissue in contact and within the thread, of fully coated HA pins was significantly lower compared to stainless steel (p=0.003, p=0.017), DLC (p=0.004, p=0.002) and HA partially coated pins (p=0.006, p=0.02).
The aim of this study was to develop a single-layer hybrid organic-inorganic sol-gel coating that is capable of a controlled antibiotic release for cementless hydroxyapatite (HA)-coated titanium orthopaedic prostheses. Coatings containing gentamicin at a concentration of 1.25% weight/volume (wt/vol), similar to that found in commercially available antibiotic-loaded bone cement, were prepared and tested in the laboratory for: kinetics of antibiotic release; activity against planktonic and biofilm bacterial cultures; biocompatibility with cultured mammalian cells; and physical bonding to the material (n = 3 in all tests). The sol-gel coatings and controls were then tested in vivo in a small animal healing model (four materials tested; n = 6 per material), and applied to the surface of commercially pure HA-coated titanium rods.Aims
Methods
Current treatments of prosthetic joint infection (PJI) are minimally effective against The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load.Aims
Methods
The December 2015 Research Roundup360 looks at: Biomarkers in periprosthetic joint infection; HbA1c and complications in arthroplasty; Getting to the bottom of biofilms; Effective antibiosis for biofilms; Stem cells and avascular necrosis; Predicting LOS in total joint arthroplasty; Long-term antibiotics reduce recurrence in periprosthetic infection