The Nramp1 antimicrobial resistance gene segregates independently of resistance to virulent Mycobacterium tuberculosis.

Nramp1 is a recently cloned gene that is involved in resistance of mice to infection with certain microbial pathogens, including the attenuated bacillus Calmette-Guérin (BCG) strain of Mycobacterium bovis, as well as certain other mycobacteria. With a view to determining whether Nramp1 influences resistance of mice to infection with virulent M. tuberculosis, BALB/c mice homozygous for the susceptibility allele of Nramp1, and DBA/2 mice homozygous for the resistance allele, as well as their F1 and F2 progeny, were typed according to their possession of these alleles using a 'hot start' polymerase chain reaction (PCR) procedure. As assessed by the ability of the mice to survive infection, the results show that Nramp1 plays no discernible role in resistance to tuberculosis.