Микобактериальные заболевания
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Detection of Mutations in rpob Gene of Clinically Isolated M. Tuberculosis by DNA Sequencing

Soniya Sharma and Molly Madan

Aim: A population-based study was performed to detect the mutations in 81-bp rifampicin resistance determining region (RRDR) of rpoB gene in clinically isolated M. tuberculosis strains.

Methods: Polymerase chain reaction (PCR) mediated direct DNA sequencing was used for rapid detection of rifampicin resistance of M. tuberculosis.

Results: Among the 150 isolates, 115 were rifampicin sensitive and exhibited a wild-type pattern on PCR mediated direct sequencing, and remaining 35 isolates were found to be resistant. The codons most frequently involved in mutation were codon 531(40%), 526(23%), and 516(15%).Total twenty four kinds of mutation, which 18 point mutation, 4 insertion & 2 deletion were observed in 81-bp RRDR region of rpoB gene.

Conclusion: The sequencing analysis for genotypic evaluation of rifampicin resistance is a highly sensitive assay and provides a practical alternative to in vitro testing in M. tuberculosis. Information on the profile of rpoB mutations in M. tuberculosis provides an improved diagnosis of rifampicin resistance by increasing the efficacy of gene sequencing based test.