Sub-minimum inhibitory concentration of rifampin: a potential risk factor for resuscitation of Mycobacterium tuberculosis

Abstract Background Mycobacterium tuberculosis possesses five resuscitation-promoting factors, Rpf A to E, which are required for the resuscitation of dormancy in mycobacteria. This study explores the transcriptional profile of all five rpfs of M. tuberculosis, in response to sub-MIC concentration of rifampin, in multidrug and mono-rifampin resistant clinical isolates. Methods Thirteen multidrug and two rifampin mono resistant clinical isolates were analyzed. Drug susceptibility testing and determination of MIC were performed. The relative expression of rpfs was measured, by real-time quantitative PCR. Results A significant upregulation of relative expression ( p rpfA , rpfB , rpfC , rpfD and rpfE , respectively. Conclusion Our results showed that the rpfs could be overexpressed in some extent in the presence of sub-MIC concentration of rifampin in multidrug and mono drug resistant M. tuberculosis . These results highlight the potential risk of sub-MIC rifampin concentrations, as a risk factor for tuberculosis reactivation.