Recovery of Mycobacterium avium after treatment with chemical decontaminants

Cell suspensions of a pathogenic strain of Mycobacterium avium, serovar 1, were tested for susceptibility to chemical disinfectants that are frequently used for decontamination of environmental samples. Kinetic data were obtained by determining the viability at 15-min intervals during 60 min of exposure at room temperature with aeration. After 60 min exposure to a combination of 0.094% Zephiran, and 10% trisodium phosphate, only 0.3% of the initial number of colony-forming units survived. Survival after 60 min treatment with 2% sodium hydroxide, 1% sodium hydroxide, or 0.04% hexadecylpyridinium chloride was 20, 46, and 57%, respectively. To assess the practical applications, the same agents were employed to extract M. avium that had been seeded into soil. Recovery of more than 25% of the initial number of colony-forming units was achieved with any of the treatments. Several combinations of chloramphenicol and antifungal drugs were tested for inhibition of soil microbiota that survived the decontamination procedures.