rpoB genotypes of Mycobacterium tuberculosis Beijing family isolates from East Asian countries

The 81-bp region of the rpoB gene in 66 Rif Mycobacterium tuberculosis isolates from China, Japan, Korea, and Taiwan was analyzed. Twelve single,nucleotide substitutions in the rpoB gene were detected. The most prevalent mutations were at Ser-531 (52%), Asp-516 (17%), and His-526 (11%). Mutations were not found in seven (11%) of the isolates. Higher mutation rates in 50 Beijing family isolates were found than in other isolates for mutations at Asp-516 (18 and 12.5%,respectively) and His-526 (12 and 6.3%, respectively). The different rates of mutation may reflect the choice of rifamycin analogs.