The Susceptibility of Strains of Mycobacterium tuberculosis to Catalase-mediated Peroxidative Killing

Abstract

At low pH and with continuous low concentrations of H2O2 generated in situ, catalase was able to replace peroxidase in the peroxidase/H2O2/iodide microbicidal system. The system was effective against Escherichia coli and M. tuberculosis. Iodide could not be replaced by chloride. The system was effective in lactate buffer, but not in citrate/phosphate buffer. Strains of M. tuberculosis with high and low virulence were equally susceptible. The possible involvement of host-cell catalase in the intracellular killing (i.e., by macrophages) of M. tuberculosis is discussed.