Clostridium infections associated with musculoskeletal-tissue allografts.

BACKGROUND: Allografts are commonly used in orthopedic reconstructive surgery. In 2001, approximately 875,000 musculoskeletal allografts were distributed by U.S. tissue banks. After the death from Clostridium sordellii sepsis of a 23-year-old man who had received a contaminated allograft from a tissue bank (Tissue Bank A), the Centers for Disease Control and Prevention initiated an investigation, including enhanced case finding, of the methods used for the recovery, processing, and testing of tissue. METHODS: A case of allograft-associated clostridium infection was defined as a culture-proven infection of a surgical site within one year after allograft implantation, from January 1998 to March 2002. We traced tissues to tissue banks that recovered and processed these tissues. We also estimated the rates of and risk ratios for clostridium infections for tissues processed by the implicated tissue bank and reviewed processing and testing methods used by various tissue banks. RESULTS: Fourteen patients were identified, all of whom had received allografts processed by Tissue Bank A. The rates of clostridium infection were 0.12 percent among patients who received sports-medicine tissues (i.e., tendons, femoral condyles, menisci) from Tissue Bank A and 0.36 percent among those who received femoral condyles in particular. The risk-ratio estimates for clostridium infections from tissues processed by Tissue Bank A, as compared with those from other tissue banks, were infinite (P<0.001) for musculoskeletal allografts, sports-medicine tissues, or tendons. Because Tissue Bank A cultured tissues only after treating them with a nonsporicidal antimicrobial solution, some test results were probably false negatives. Tissues from implicated donors were released despite the isolation of clostridium or bowel flora from other anatomical sites or reports of infections in other recipients. CONCLUSIONS: Clostridium infections were traced to allograft implantation. We provide interim recommendations to enhance tissue-transplantation safety. Tissue banks should validate processes and culture methods. Sterilization methods that do not adversely affect the functioning of transplanted tissue are needed to prevent allograft-related infections.

Surface sampling methods for Bacillus anthracis spore contamination.

During an investigation conducted December 17-20, 2001, we collected environmental samples from a U.S. postal facility in Washington, D.C., known to be extensively contaminated with Bacillus anthracis spores. Because methods for collecting and analyzing B. anthracis spores have not yet been validated, our objective was to compare the relative effectiveness of sampling methods used for collecting spores from contaminated surfaces. Comparison of wipe, wet and dry swab, and HEPA vacuum sock samples on nonporous surfaces indicated good agreement between results with HEPA vacuum and wipe samples. However, results from HEPA vacuum sock and wipe samples agreed poorly with the swab samples. Dry swabs failed to detect spores >75% of the time when they were detected by wipe and HEPA vacuum samples. Wipe samples collected after HEPA vacuum samples and HEPA vacuum samples collected after wipe samples indicated that neither method completely removed spores from the sampled surfaces.