Bacterial Contamination of Autologous Bone Flaps: Investigation and Targeted Antibiotic Treatment

Objective Bacteria present on extracted bone flaps during decompressive craniectomy inhibit bone flap reimplantation. An adapted treatment with antibiotic mixture for decontamination of allografts could be used in neurosurgery for preparation of bone flaps for autologous cranioplasty. Methods Eleven bone flaps were analysed using standardised bacterial cultures and droplet digital Polymerase Chain Reaction (ddPCR). Growth of Cutibacterium acnes , Staphylococcus aureus, and other Staphylococci species were detected. Bone flaps were treated with antibiotic mixtures for 24 hours before evaluating the antibacterial effect by measuring colony forming units (CFU) reduction. Results Bacterial prevalence was in substantial agreement between standard culture methods and detection by ddPCR. Fragmentation of the bone revealed heterogeneous bacterial loads across fragments, consistent with the distribution of bacterial species commonly found in sample skin contamination. A 24-hour antibiotic treatment (mixture of gentamicin, vancomycin and cefotaxime) reduced the CFU of all detectable bacteria on the bone flaps. Conclusion Treatment of bone flaps with antibiotic mixture containing gentamicin, vancomycin and cefotaxime for 24 hours can effectively eradicate commonly identified bacteria, including Cutibacterium acnes and coagulase-negative Staphylococci from the bone tissue.