Catalase Activity and Its Heat Inactivation for Differentiation of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum

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Abstract
The catalase activities of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum strains were measured. M. intracellulare and M. avium had significantly lower activities than M. scrofulaceum. The percentage of catalase activity remaining after exposure of cell-free extracts from late-log-phase cells to 53°C for 50 min allowed differentiation among the three species; M. intracellulare catalase retained 14.1 ± 7.9% (mean ± standard deviation) of its activity, M. avium retained 53.3 ± 7.4% of its activity, and M. scrofulaceum catalase was very resistant and retained 82.8 ± 6.7% of its activity. Cells of all three species harvested in stationary phase exhibited higher percentages of heat-resistant catalase, and species could not be differentiated at this stage in the growth cycle. Polyacrylamide gel electrophoresis of crude extracts from late-log-phase cells produced two bands of catalase activity in both M. intracellulare and M. avium extracts and four bands of activity in M. scrofulaceum extracts stained by diaminobenzidine. These bands differed in their susceptibilities to heat inactivation and inhibition by 3-amino-1,2,4-triazole.