Bacterial contamination of allografts.

The risk of bacterial infection through allogenic bone transplantation is one of the major problems facing tissue banks. The purpose of this study is to report the contamination rate in 987 grafts obtained under strictly aseptic conditions, between 1989 and 1992. The grafts were stored at -80 degrees C (cortical bone and tendons) and -40 degrees C (cancellous bone). The overall contamination rate was 6.6%, with Gram-positive bacteria responsible for 80% of the positive cultures. We discuss the sources of contamination, the most frequently isolated bacteria and the steps in the donation and transplantation procedures that help to reduce the risk of contamination. We conclude that the methods of acquisition, processing and storage of tissues are effective in making sterile allografts available.