Sulfamethoxazole enhances the antimycobacterial activity of rifampicin.

Objectives: To investigate the effect of trimethoprim/sulfamethoxazole on the survival of Mycobacterium tuberculosis and trimethoprim and sulfamethoxazole individually and combined with the first-line tuberculosis drugs (isoniazid, rifampicin and ethambutol).

Methods: M. tuberculosis strains were exposed to either trimethoprim/sulfamethoxazole combination or sulfamethoxazole and trimethoprim alone at various concentrations.

Glutamate dehydrogenase and glutamine synthetase are regulated in response to nitrogen availability in Myocbacterium smegmatis.

Background: The assimilation of nitrogen is an essential process in all prokaryotes, yet a relatively limited amount of information is available on nitrogen metabolism in the mycobacteria. The physiological role and pathogenic properties of glutamine synthetase (GS) have been extensively investigated in Mycobacterium tuberculosis. However, little is known about this enzyme in other mycobacterial species, or the role of an additional nitrogen assimilatory pathway via glutamate dehydrogenase (GDH), in the mycobacteria as a whole.

Regulation of nitrogen metabolism in Mycobacterium tuberculosis: a comparison with mechanisms in Corynebacterium glutamicum and Streptomyces coelicolor.

The mechanisms governing the regulation of nitrogen metabolism in Corynebacterium glutamicum and Streptomyces coelicolor have been extensively studied. These Actinomycetales are closely related to the Mycobacterium genus and may therefore serve as a models to elucidate the cascade of nitrogen signalling in other mycobacteria. Some factors involved in nitrogen metabolism in Mycobacterium tuberculosis have been described, including glutamine synthetase and its adenylyltransferase, but not much data concerning the other components involved in the signalling cascade is available.