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

The most challenging complications in orthopaedic trauma surgery are fracture-related infections (FRI). The incidence ranges from approximately 1% after closed fractures or joint replacement, to more than 30% in complex open limb fractures. Despite tremendous efforts with prolonged antibiotic therapy and multiple revision surgeries, these complications are associated with considerable rates of recurrent infections as well as permanent functional impairment. The primary aim for the clinician is to prevent infection, because once established, an infection is difficult to eradicate. The main reason for this is biofilm formation on the implanted device, which allows pathogens to protect themselves from host immune response and antimicrobial therapy. In open fractures with a considerable wound contamination and soft- tissue damage, systemically-delivered antibiotics may not reach sufficient local concentrations to eradicate the bacteria. Locally delivered antibiotics can overcome this problem by providing high local concentrations. Currently, several antibiotic loaded biomaterials for local infection prophylaxis and/or treatment are available. In this talk, next to the diagnostic challenges of FRIs, the currently available antimicrobial-loaded biomaterials will be described. Against a backdrop of increasing infection and antimicrobial resistance, the prudent use and availability of such materials will become even more important