Analysis of the Molecular Evolution of the Mycobacterium Tuberculosis Drug-Resistant Gene rpoB in Asia Using a Bayesian Evolutionary Method.

Background: Tuberculosis (TB) is a serious communicable disease throughout the world. Re-emergence of the TB epidemic is aggravated by the circulation of multidrug-resistant Mycobacterium tuberculosis strains, and more than half of new cases have occurred in Asia. Therefore, it is important to understand the gene mutations underlying the development of rifampicin resistance in Asia.

Methods: In this study, we classified the rifampicin-resistant Mycobacterium tuberculosis (MTB) rpoB data downloaded from Genbank, based on 12 mutation points. The relationship between the mutation sites and regional information was analyzed, after which the mutation dates and mutation trends of the rpoB gene were predicted by the Markov Chain Monte Carlo (MCMC) method.

Results: We discovered that the mutation sites of the rpoB gene were disparate in different regions of Asia. The results of this study clearly showed that drug-resistant gene mutations in Asia started to increase in 2000 and peaked in 2006, indicating the relationship between drug resistance and outbreak trends of TB.

Conclusions: From our analysis, it was not difficult to see the relationship between the mutation rates of the rpoB gene and the outbreak of TB. Hence, to some degree, outbreak trends of TB can be predicted through genotyping based on the rpoB gene.