Risk factors for escherichia coli growth in preprocessing cultures of musculoskeletal allograft tissue

Background: Each year, approximately 1.3 million cadaveric musculoskeletal allografts are used in orthopedic procedures. The Centers for Disease Control and Prevention has identified Escherichia coli as a common cause of allograft-associated infections. Thus, the Food and Drug Administration (FDA) has issued new standards requiring tissue banks to obtain pre-processing cadaveric tissue cultures. We conducted this study to identify risk factors associated with E. coli contamination of pre-processing allograft tissues. Methods: This was a case-control study: cases were defined as cadaveric donors with positive cultures for E. coli during January-May 2003. Controls were randomly selected donors with negative cultures during the same period. Results: Twenty-four cases and forty-nine controls were ascertained. Risk factors included dissection performed by fewer than three personnel (OR= 5.6, CI: 1.49-21.27, p=0.006); death outside the hospital versus inpatient (OR= 3.7, CI: 1.23-11.24, p=0.017); and procurement following autopsy (p=0.003). Place of tissue recovery (hospital vs. non-hospital) was not associated with contamination (OR=1.49, CI: 0.46-4.9, p= 0.507). Conclusions: Regulatory agencies (e.g., FDA) and the American Association of Tissue Banks (AATB) need data from studies like this to formulate guidelines for recovery and processing of allograft tissues. Public Health Significance: With millions of allografts being implanted every year, data like these are necessary to enhance patient safety.