Molecular and epidemiological characterization of rpoB mutations in rifampicin-resistant Mycobacterium tuberculosis in Kyrgyz Republic

The nature and frequency of mutations in the rpoB gene of M. tuberculosis (MBT) vary considerably in various geographical locations. There is no information on the prevalence of specific mutations in the rpoB gene of MBT isolated from patients in Kyrgyz Republic. In this work, we analyzed a distribution of the rpoB gene mutations in Kyrgyz Republic. A total of 380 rifampicin-sensitive and 225 rifampicin-resistant MBT cultures were analyzed to identify and to characterize mutations in the rpoB gene using a biological microchip assay. The biochip test determined 18 different mutation types in 8 codons of the rifampicin-resistant samples. The majority of mutations (180 of 225, or 80 %) were in the codons 531 and 526, mainly in the codon 531 (137 of 225, 60.8 %). The Ser531>Leu mutation (134 of 225, 59.4 %) was by far the most common. Another group of mutations were in the codon 526 (43 of 225, 19.1 %). Five different types of mutations were found in the codon 526 which were: His526®Tyr (4.9 %), His 526®Asp (4.9 %), His526®Arg (4.0 %), His526®Leu (3.5 %), and His526®Pro (1.8 %). The third group of common mutations were Leu511®Pro (6.3 %) and Asp516®Tyr (4.4 %). Other mutations found in the codons 533, 522, 513, and 512 were less frequent and had a very low rate comprising about 1.8 % of the total mutation number among 225 rifampicinresistant samples.

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