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

Orthopedic device-related bone infection is one of the most distressing complications of the surgical fixation of fractures. Despite best practice in medical and surgical interventions, the rate of infection remains stubbornly persistent, and current estimates indicate that treatment failure rates are also significant. As we approach the limit of the effectiveness of current anti-infective preventative and therapeutic strategies, novel approaches to infection management assume great importance. This presentation will describe our efforts to develop and test various hydrogels to serve as customized antibiotic delivery vehicles for infection prevention and treatment. Hydrogels offer solutions for many of the challenges faced by complex trauma wounds as they are not restricted spatially within a poorly defined surgical field, they often degrade rapidly with no compatibility issues, and releases 100% of the loaded antibiotic. The preliminary data set proving efficacy in preventing and treating infection in both rabbit and sheep studies will be described, including local antibiotic concentrations in the intramedullary canal over time, compared to that of the more conventional antibiotic loaded bone cement. These two technologies show potential for the prevention and treatment of infection in trauma patients, with a clear focus on optimized antibiotic delivery tailored for complex wounds

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 arthroplasty 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 (123 mW/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 (greater than a 4-log reduction) was achieved for all of the clinical isolates from infected arthroplasty cases. The typical inactivation curve showed a slow initial reaction followed by a period of rapid inactivation. The doses of HINS-light exposure required ranged from 118–2214 J/cm. 2. respectively. Gram-positive bacteria were generally found to be more susceptible than Gram-negative. 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

Implant infection is an increasing problem in orthopedic surgery, especially due to progressive antibiotic resistance and an aging population with rising numbers of implantations. As a consequence, new strategies for infection prevention are necessary. In the previous study it was hypothesized that laser-structured implant surfaces favor cellular adhesion while hindering bacterial ongrowth and therewith contribute to reduce implant infections. Cuboid titanium implants (0.8 × 0.8 × 12 mm. 3. , n=34) were used. Seventeen were laser-structured by ultra-short pulsed laser ablation to create a spike structure; the others were polished and served as controls. In general anesthesia, implants were inserted in rat tibiae and infected with a S. aureus suspension. During a 21 day postoperative follow-up, daily clinical control was performed. Radiographs were taken at day 14 and day 21. After euthanasia, bacterial load and biofilm formation on the implant surface was evaluated semi quantitatively by confocal laser scanning microscopy and computational acquisition of bacteria and cells by Imaris®-software. Additionally, histology of the surrounding bone was performed. Clinically, no differences were observed between the groups. However, contrary to our hypothesis, bacterial load was increased in the laser-structured implant group although cellular adhesion was even more pronounced. Radiographical and histological evaluations showed increased bone alterations in the group with laser-structured implants compared to the control group. These findings did not confirm prior in vitro studies, where a reduction of bacterial load was found for similar surfaces and demonstrate the necessity of in vivo trials prior to the clinical use of new materials

Introduction. One method of surgical site infection prevention is lowering intraoperative environmental contamination. We sought to evaluate our hospitals operating room (OR) contamination rates and compare it to the remainder of the hospital. We tested environmental contamination in preoperative, intraoperative and postoperative settings of a total joint arthroplasty patient. Materials & Methods. 190 air settle plates composed of trypsin soy agar (TSA) were placed in 19 settings within our hospital. Locations included the OR with light and heavy traffic, with and without masks, jackets, and shoe covers, sub-sterile rooms, OR hallways, sterile equipment processing center, preoperative areas, post-anesthesia care units, orthopaedic floors, emergency department, OR locker rooms and restrooms, a standard house in the local community, and controls. The plates were incubated in 36 degrees celsius for 48 hours and colony counts were recorded. Numbers were averaged over each individual area. Results. The highest CFU was the OR locker room at 28 CFU/plate/hr. Preoperative & post anesthesia care unit holding areas were 7.4 CFU & 9.6 CFU, respectively. The main orthopaedic surgical ward had 10.0 CFU/plate/hr, while the VIP hospital ward had 17.0 CFU/plate/hr. The OR environment all had low CFUs. A live OR had slightly higher CFUs than ones without OR personnel. The OR sub-sterile room had 5.2 CFU/plate/hr, and the OR hallway had 11.2 CFU/plate/hr. The local community household measured 5.6CFU/plate/hr. Discussion. In comparison to the local community household, the OR locker room, restrooms, hospital orthopaedic wards, ED, pre-operative holding, PACU and OR hallway all had higher airborne contamination than the local household in our surrounding community. We were surprised to find some areas with high rates of contamination. Our hospital has since increased environmental cleaning and monitoring of these areas with improved effect. Based on our results, we can recommend environmental sampling as a simple, fast, inexpensive tool to monitor airborne contamination