The expression of ABC efflux pump, Rv1217c-Rv1218c, and its association with multidrug resistance of Mycobacterium tuberculosis in China.

Currently the treatment of Mycobacterium tuberculosis (TB) infection is largely limited due to the prevalence of multidrug resistance strains. Over-expressing the efflux pumps such as the ATP-binding cassette (ABC) transporter has been reported to significantly contribute to its resistance to several antibiotics. This study investigated the expression profile of one important ABC efflux pump, Rv1217c-Rv1218c, by quantitative real-time PCR (RT-qPCR) in clinical isolates from China, which also revealed its association with the multidrug resistance of M. tuberculosis. Significantly increased expressions of Rv1217c and Rv1218c at transcriptional level have been observed in multidrug-resistant TB group (MDR-TB) compared to those of the drug-susceptible group (P < 0.05), when H37Rv strain was used as the control. Furthermore, correlation analysis revealed that the over-expression of both Rv1217c and Rv1218c resulted in the higher minimum inhibition concentrations (MICs) of rifampicin (RIF) (OR = 1.01, P < 0.05 of Rv1217c; OR = 1.23, P < 0.05 of Rv1218c), while the over-expression of Rv1218c only led to the higher MICs of isoniazid (INH) (OR = 1.17, P < 0.05). Our findings contributed to the better understanding of the molecular mechanisms of ABC efflux pumps, in particular Rv1217c-Rv1218c, in M. tuberculosis and will assist in developing new antibiotic treatments for multidrug-resistant M. tuberculosis in the future.