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Updated: Jan 30, 2026

Growth of Mycobacterium tuberculosis Biofilms
Published on: February 15, 2012
Modulatory effects of verapamil in rifampicin activity against Mycobacterium tuberculosis
Katiany R Caleffi-Ferracioli1, Rosilene F Cardoso1, João Vp de Souza1
1Laboratory of Medical Bacteriology, Department of Clinical Analysis & Biomedicine, State University of Maringa, Parana, Brazil.
Aim:
To evaluate modulatory effect of verapamil (VP) in rifampicin (RIF) activity and its effect in efflux pumps (EPs) transcript levels in Mycobacterium tuberculosis.
Materials & Methods:
RIF and VP minimal inhibitory concentration, combinatory effect and detection of mutations were determined in 16 isolates. EPs transcript levels were determined in four isolates by real-time PCR after exposure to drugs.
Results:
VP showed good combinatory effect among RIF-resistant isolates. This effect was also observed in the relative transcript levels of EPs, mainly after 72 h of exposure, depending on the EP gene, genotype and the resistance profile of the isolate.
Conclusion:
Additional regulatory mechanisms in the EP activities, as well as, interactions with other drug-specific resistance mechanisms need further investigation in M. tuberculosis.
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