Insight into multidrug-resistant Beijing genotype Mycobacterium tuberculosis isolates in Myanmar

Myanmar is a World Health Organization high tuberculosis (TB) burden country with a high multidrug-resistant (MDR)-TB burden. Of significance, a high prevalence of the Beijing genotype of Mycobacterium tuberculosis (MTB) among MDR-MTB has been reported previously. A detailed genetic characterization of TB clinical isolates was performed in order to explore whether there is an association between the prevalence of the Beijing MTB genotype and MDR-TB in Myanmar.

A total of 265 MDR-MTB clinical isolates collected in 2010 and 2012 were subjected to spoligotyping, mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis, single nucleotide polymorphism (SNP) typing, and drug resistance-associated gene sequencing, including rpoC to detect potential compensatory evolution.

Of the total MDR-MTB isolates, 79.2% (210/265) were of the Beijing genotype, the majority of which were the 'modern' subtype. Beijing genotype isolates were differentiated by 15-locus MIRU-VNTR and a high clustering rate (53.0%) was observed in the modern subtype. These MIRU-VNTR patterns were similar to Beijing genotype clones spreading across Russia and Central Asia. A high prevalence of katG Ser315Thr, and genetic evidence of extensive drug resistance (XDR) and pre-XDR and compensatory mutations in rpoC were observed among clustered isolates.

MDR-MTB strains of the Beijing genotype might be spreading in Myanmar and present a major challenge to TB control in this country.