Evaluation of MICRO

MICRO-CHEM PLUS Detergent Disinfectant Cleaner (MCP) is a commonly used disinfectant at biosafety level 4 (BSL-4) laboratories where research activities involving the most dangerous pathogens must be conducted. Using bat severe acute respiratory syndrome (SARS)–like coronavirus (CoV) WIV1 as a surrogate pathogen, we extensively evaluated the disinfection efficacy of 5% MCP in the first BSL-4 laboratory in China. WIV1 was completely inactivated in 1 minute of contact time by a 27-fold dilution of 5% MCP with a titer reduction of more than 7 lg 50% tissue culture infectious dose (TCID50)/mL, while a 243-fold dilution of 5% MCP showed very weak activity. For 81-fold dilution, WIV1 was killed by more than 6 lg TCID50/mL in 1 minute, but to get complete inactivation, the contact time should be at least 2 minutes. No loss of efficacy was detected for 5% MCP at a temperature of 0°C, ambient, or 37°C or in the solution of pH 3.2 to 12.2. No interference to disinfection efficacy was detected with up to 25% fetal bovine serum, 5% bovine serum albumin, or 8% cell debris. The decontamination of a positive pressure suit by chemical shower was tested with the filter pieces taped onto the head, chest, back, armpits, crotch, and boot soles, and no virus survived after a shower cycle of 4 minutes at 5% MCP plus 2 minutes of a soft water rinse. Keeping the ambient temperature for 79 days or in the tank for the chemical shower for 25 days, 5% MCP showed the same activity as when it was freshly prepared. Taken together, 5% MCP is a very efficient disinfectant for BSL-4 laboratories, and we recommend its application for other enveloped viruses