Bacterial contamination of bone allografts in the tissue banks: a systematic review and meta-analysis

Bone allografts are harvested and transplanted under sterile conditions. However, the risk of bacterial contamination of grafts during these processes is a health concern. Bioburden testing and bacterial contamination detection are conducted to ensure allograft sterility. The present study aimed to determine the incidence of bacterial contamination in bone allografts based on different classifications. A PROSPERO registration number was received for the study. Systematic searches were conducted in PubMed and EMBASE databases with relevant keywords from January 2000 to March 2021. After choosing related studies according to the PRISMA flow diagram, Stata software was used for data analysis. We considered I2˃50% as heterogeneity between studies. The overall incidence of bacterial contamination was 12.6% (95% confidence interval 0.100, 0.152) among 19,805 bone allografts of 17 studies. The bacterial contamination rate among bone allografts was 10.8% before 2010 and 14.7% from January 2010 to March 2021. The contamination frequency in Asia, Europe, and Australia was 11.5%, 14.3% and 5.2%, respectively. Bone contamination rates were higher in cadaver donors (19.9%), retrieval time sampling (13.5%), and swab samples (13.2%) compared with those in living donors (7.5%), implantation time sampling (6.9%), and bone fragments cultures (6.3%). Bacterial contamination was recovered 24.4%, 19.7%, 13.2%, and 21% from tibia, fibula, femoral, and other bones, respectively. Staphylococcus spp. was the predominant isolated bacteria from bones (63.2% of all isolated genera), followed by Propionibacterium spp. (10.6%). In conclusion, the high contamination of bone allografts is a health concern, indicating the need for more health monitoring and improvement of standards.