eis Promoter C14G and C15G Mutations Do Not Confer Kanamycin Resistance in Mycobacterium tuberculosis

Area of Science:

• Microbiology
• Genetics
• Drug Resistance

Background:

• Mycobacterium tuberculosis (M. tuberculosis) poses a significant global health challenge.
• Antimicrobial resistance in M. tuberculosis complicates treatment regimens.
• The eis gene's role in drug resistance requires further elucidation.

Purpose of the Study:

• To investigate the impact of specific eis promoter mutations on Mycobacterium tuberculosis drug resistance.
• To determine the minimum inhibitory concentrations (MICs) for kanamycin and amikacin in recombinant M. tuberculosis strains with eis mutations.

Main Methods:

• Utilized a specialized transduction strategy to create recombinant M. tuberculosis strains.
• Introduced specific eis promoter mutations (C14T, C12T, G10A, C14G, C15G).
• Determined kanamycin and amikacin MICs for each recombinant strain.

Main Results:

• eis promoter mutations C14T, C12T, and G10A conferred kanamycin resistance (MICs 40, 10, and 20 μg/ml).
• eis mutations C14G and C15G resulted in kanamycin susceptibility (MIC 2.5 to 5 μg/ml).
• All tested eis mutants remained susceptible to amikacin (MIC 0.5 to 4 μg/ml).

Conclusions:

• Specific eis mutations are directly linked to kanamycin resistance in M. tuberculosis.
• Genotypic susceptibility testing for kanamycin requires the identification of these precise eis mutations.
• Understanding eis mutation profiles can guide targeted M. tuberculosis treatment strategies.