Characterization of rpoB mutations by line probe assay in rifampicin-resistant Mycobacterium tuberculosis clinical isolates from the Aegean region in Turkey

Abstract

The nature and frequency of mutations in the rpoB gene of rifampicin (RIF)-resistant Mycobacterium tuberculosis clinical isolates vary considerably according to the geographical location, and very little information is available regarding specific mutational patterns in our country. The main objective of this study was to determine the frequency of mutations in the hypervariable region of the rpoB gene in RIF-resistant M. tuberculosis isolates recovered from tuberculosis patients in our region by using the INNO-LiPA Rif. TB kit and to evaluate the performance of the kit for the detection of RIF-resistance. Mutations associated with RIF resistance were studied by line probe assay (LiPA) in 65 RIF-resistant and 56 RIF-susceptible M. tuberculosis strains isolated from different patients in the Aegean region of Turkey. The LiPA identified all susceptible strains (100%) as RIF-sensitive and 63 of 65 (96.9%) phenotypically documented RIF-resistant M. tuberculosis isolates as RIF-resistant, with specific detection of mutation in 44 (67.7%) isolates, whilst 2 strains were identified as RIF-susceptible. The R5-pattern (Ser-531-Leu mutation) was the most frequently observed (35 of 65, 53.8%), followed by the ΔS2-pattern (7.7%) and ΔS4-pattern (7.7%).