Validating an Autoclave Cycle for Sterilization of Select Agent-Infected Murine Carcasses

Introduction: Infectious disease research conducted in the Duke Regional Biocontainment Laboratory, a biosafety level-3 facility, often includes work with mice. Infected carcasses must be properly decontaminated at the completion of each study and prior to removal from the facility. Working with Select Agents requires validated methods for complete inactivation of the agent before carcasses can be removed from registered spaces. Methods: Biological indicators were implanted into the abdomen of unfrozen mouse carcasses, then autoclaved using different cycle parameters and packaging strategies to determine the best approach to ensure complete sterilization. Results: Both 20-min and 30-min autoclave cycles at 122°C, with three pre-vacuum pulses, failed to consistently sterilize unfrozen mouse carcasses. A 45-min autoclave cycle with the same parameters did result in the successful sterilization of carcasses when packaged at two or four carcasses in an 8” × 12” autoclave bag. Conclusions: This study supports the utilization of an autoclave cycle (122°C sterilization temperature, 45-min sterilization time, three pre-vacuum pulses) to sterilize unfrozen mouse carcasses, up to four per bag.