Bacterial Contamination of Autologous Cranial Bone Flaps: Microbiological Analysis and In Vitro Antibiotic Decontamination.

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 analyzed using standardized bacterial cultures and droplet digital polymerase chain reaction. 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 reduction.

RESULTS

Bacterial prevalence was in substantial agreement between standard culture methods and detection by droplet digital polymerase chain reaction. 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 colony forming unit of all detectable bacteria on the bone flaps.

CONCLUSIONS

Treatment of bone flaps with antibiotic mixture containing gentamicin, vancomycin, and cefotaxime for 24 hours can effectively eradicate commonly identified bacteria, including C. acnes and coagulase-negative Staphylococci from the bone tissue.

CLINICAL RELEVANCE: Usage of antibiotic mixtures for eradication of bacteria detected on bone flaps, could be considered as a method for preservation of bone flaps and potential reduction of surgical site infection risk.