Acetate utilization pathways in Mycobacterium tuberculosis, a potential pathogen in maize silage

Abstract

Acetic acid is an important component of maize silage, which imparts stability to silage against damage by aerobic conditions. Inoculation of maize fodder with heterofermentative lactic acid bacteria results in formation of acetic acid. The drop in pH that results in ensiled fodder inhibits growth of undesirable organisms. However, certain organisms have developed mechanisms to survive in hostile conditions. Of particular interest is the notorious human pathogen, Mycobacterium tuberculosis which had been implicated as a potential pathogen of maize silage. The conditions in silage like availability of magnesium confer advantage to many species of the Mycobacterium tuberculosis complex by stabilizing certain proteins, enabling the organism to survive under the otherwise harsh conditions. In this article, the possible routes of acetate conversion in ten strains of M. tuberculosis, to acetylCoenzyme A, an important intermediate in energy metabolism have been deciphered from a curated metabolic pathway repository. The results implicate that metabolic flexibility in M. tuberculosis strains constitutes a strategy for enhanced pathogen survival under adverse conditions. The diversity in utilization of acetate and other carbon sources necessitate an investigation of mycobacterial survival strategies for a more informed Quality Control of maize silage for applications in dairy industry.