Chlorine, chloramine, chlorine dioxide, and ozone susceptibility of Mycobacterium avium

Abstract

Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water.

FIG. 1

M. avium disinfection kinetics for a chlorine concentration of 1.0 ± 0.2 ppm (pH 7.0; temperature, 23°C). The error bars indicate the 95% confidence intervals.

FIG. 2

M. avium strain 5002 disinfection kinetics with different concentrations of chlorine dioxide (pH 7.0; temperature, 23°C). The curve is a best fit linear regression line created with the Sigma Plot program (Jandel Scientific, San Rafael, Calif.).