Comparison of different drug susceptibility test methods to detect rifampin heteroresistance in Mycobacterium tuberculosis.

We compared the efficiencies of different drug susceptibility testing methods in detecting rifampin (RIF) heteroresistance in Mycobacterium tuberculosis. Our data revealed that the broth dilution method found more resistance than MGIT did (P=0.046) for the low-resistance group. Similarly, the broth dilution method was more sensitive in detecting RIF heteroresistance in subpopulations with low growth rates than was MGIT (P=0.033). In conclusion, our data demonstrated that the broth dilution method was more sensitive than MGIT in detecting RIF heteroresistance.