Comparative evaluation of bioburden and sterility of indigenously prepared bone allograft with and without gentamicin

During bone allograft processing, despite stringent donor screening and use of aseptic techniques, microbial invasion may occur due to the porous nature of the graft and cause potentially fatal infections. The aim of the present study was to prepare bone allograft with and without gentamicin and to compare bioburden and sterility in the obtained grafts to evaluate the role of antibiotic in enhancing graft safety. Fifty samples of demineralized freeze-dried bone allograft were prepared from suitable donors according to international standards. Randomly selected 25 samples were placed in 8 mg gentamicin/gram bone solution for 1 h. Packaging and sealing was done to ensure no microbial ingress during transportation. 40 samples were selected for bioburden testing. Remaining 10 were subjected to 25 kGy gamma radiation and tested for sterility. Microbiological evaluation revealed no evidence of colony forming units in all the samples of both the groups (Bioburden = 0). Post-radiation sterility testing also revealed no bacterial colony in the tested samples from both the groups. Favorable results validate the processing protocol while comparable results in both groups indicate no additive benefit of gentamicin addition. Nil bioburden may be used in further studies to determine a lower radiation dose to achieve adequate sterility and minimize the disadvantages of radiation like collagen cross-linking and decreased osteoinductive capacity.