A Rifampin-Hypersensitive Mutant Reveals Differences between Strains of Mycobacterium smegmatis and Presence of a Novel Transposon, IS1623

AUTOR(ES)

Alexander, David C.

FONTE

American Society for Microbiology

RESUMO

Rifampin is a front-line antibiotic for the treatment of tuberculosis. Infections caused by rifampin- and multidrug-resistant Mycobacterium tuberculosis strains are difficult to treat and contribute to a poor clinical outcome. Rifampin resistance most often results from mutations in rpoB. However, some drug-resistant strains have rpoB alleles that encode the phenotype for susceptibility. Similarly, non-M. tuberculosis mycobacteria exhibit higher levels of baseline resistance to rifampin, despite the presence of rpoB alleles that encode the phenotype for susceptibility. To identify other genes involved in rifampin resistance, we generated a library of Mycobacterium smegmatis mc2155 transposon insertion mutants. Upon screening this library, we identified one mutant that was hypersensitive to rifampin. The transposon insertion was localized to the arr gene, which encodes rifampin ADP ribosyltransferase, an enzyme able to inactivate rifampin. Sequence analysis revealed differences in the arr alleles of M. smegmatis strain mc2155 and previously described strain DSM 43756. The arr region of strain mc2155 contains a second, partial copy of the arr gene plus a novel insertion sequence, IS1623.

Documentos Relacionados

• Mechanism of Action of Rifampin on Mycobacterium smegmatis
• Characterization of a Mycobacterium smegmatis Mutant That Is Simultaneously Resistant to d-Cycloserine and Vancomycin
• Ribosylative inactivation of rifampin by Mycobacterium smegmatis is a principal contributor to its low susceptibility to this antibiotic.
• A Mutant of Mycobacterium smegmatis Defective in Dipeptide Transport
• Multidrug Resistance of a Porin Deletion Mutant of Mycobacterium smegmatis