RESUMO
Incubation by means of the growth-promoting factor VCG of autoclaved culture broth of M. bovis 8 and tuberculins on the nutrient medium VCG gave rise to microorganisms that could partially restore acid resistance. The isolates reacted with antiserum to M. bovis Vallee in the agglutination test and enzyme immunoassay, which in combination with polymerase chain reaction data verifies their genetic relationship with the pathogen of tuberculosis. The isolates did not show a significant pathogenicity, but they long persisted in guinea-pigs and, in some cases, induced delayed hypersensitivity to tuberculin. When exposed to high temperatures, the pathogen of tuberculosis is presumably to form structures that are capable to restore viability under certain conditions (for example, on the VCG medium).