Open AccessAsnB Is Involved in Natural Resistance of Mycobacterium smegmatis to Multiple Drugs
Author(s) -
Hui Ren,
Jun Liu
Publication year - 2006
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.50.1.250-255.2006
Subject(s) - mycobacterium smegmatis , microbiology and biotechnology , mycobacterium , mycobacterium tuberculosis , chemistry , bacteria , pharmacology , biology , medicine , tuberculosis , genetics , pathology
Mycobacteria are naturally resistant to most common antibiotics and chemotherapeutic agents. The underlying molecular mechanisms are not fully understood. In this paper, we describe a hypersensitive mutant ofMycobacterium smegmatis , MS 2-39, which was isolated by screening for transposon insertion mutants ofM. smegmatis mc2 155 that exhibit increased sensitivity to rifampin, erythromycin, or novobiocin. The mutant MS 2-39 exhibited increased sensitivity to all three of the above mentioned antibiotics as well as fusidic acid, but its sensitivity to other antibiotics, including isoniazid, ethambutol, streptomycin, chloramphenicol, norfloxacin, tetracycline, and β-lactams, remained unchanged. Uptake experiment with hydrophobic agents and cell wall lipid analysis suggest that the mutant cell wall is normal. The transposon insertion was localized within theasnB gene, which is predicted to encode a glutamine-dependent asparagine synthetase. Transformation of the mutant with wild-typeasnB of mc2 155 orasnB ofMycobacterium tuberculosis complemented the drug sensitivity phenotype. These results suggest that AsnB plays a role in the natural resistance of mycobacteria.