Abstract
The importance of some putative efflux pumps in conferring drug resistance on certain strain of Mycobacterium tuberculosis was determined by using multidrug-resistant (MDR) strain 1499 bearing defined mutations in rpoB and katG. The clinical isolate 1499 was tested for drug sensitivity and expression level of five putative efflux pump genes by real-time RT-PCR. In the presence of rifampicin or isoniazid, this isolate showed increased transcription of putative efflux pump genes Rv1258c and Rv1410c. Rv1819c was overexpressed only upon isoniazid exposure (p < 0.05). Overexpression of some efflux genes is associated with multidrug resistance in certain clinical isolate of M. tuberculosis.