Attenuation of Isoniazid-resistant Mutants of Tubercle Bacilli and Host Hypersensitivity to Tuberculin.

Abstract

Isoniazid-resistant, catalase-deficient strains of tubercle bacilli are much less pathogenic for hamsters than for CFI mice. Neither of these species of animals manifests much tuberculin hypersensitivity during the course of tuberculous infection. Therefore, the attenuation of catalase-deficient strains of tubercle bacilli does not appear to be dependent upon the ability of the host to develop tuberculin hypersensitivity. Quantitatively controlled airborne-infection experiments with 5 different strains of tubercle bacilli are described.