Studies of a novel agent possessing resistance to moist heat and disinfectants: parallels with Creutzfeldt-Jakob agent.

The resistance to sterilization and disinfection of a novel replicating agent (IFDO) with similarities to Creutzfeldt-Jakob agent (CJA) was investigated. Moist heat at 121 degrees C for 30 min did not kill the agent. Increasing the temperature to 140 degrees C, and the length of the autoclave cycle to 120 min also failed to guarantee sterilization, although some samples were sterilized after these treatments. Dry heat at 160 degrees C for 1 h sterilized 24 of 25 samples. Overnight disinfection with 10% Stericol or 1.2% chlorhexidine left few detectable survivors. Samples pretreated with these disinfectants and then autoclaved at 134 degrees C for 20 min were sterilized. Disinfection with hypochlorite (500 ppm available chlorine) was very effective if organic matter derived from spent culture medium was removed. We have adopted overnight Stericol disinfection, followed by autoclaving at 134 degrees C for 1 h for sterilization of glassware contaminated by IFDO. The agent may provide a valid model for sterilization of items contaminated with CJA and, if so, our data suggest that current disinfection guidelines for CJA by autoclaving at 134 degrees C for 1 h are inadequate.