Microbial pathogenesis: an insight into Mycobacterium tuberculosis.

Tuberculosis, as yet, is far from being controlled. Several reasons can be attributed to this, a major contributing factor being the development of resistance to the currently available drugs due to the successful adaptation of the pathogen. Most of the inferences about the pathogen are based on the observation of mycobacteria grown in synthetic media in vitro and of the mycobacteria maintained in macrophages simulating the in vivo conditions. Molecular studies in mycobacteria had been slow to come due to the difficulty in the generation of mutants. However, new technologies that have now been developed for studying in vivo expressed molecules in other bacterial systems are being successfully applied to mycobacteria, especially the pathogenic M. tuberculosis. Additionally, an equally important factor in the study of the disease is the genetic predisposition of population to the infection. New findings link the Nramp1 and Toll receptor polymorphisms to susceptibility to infectious diseases.