Open AccessPlate‐based dormancy culture system for Mycobacterium smegmatis and isolation of metronidazole‐resistant mutants
Author(s) -
Lim Amanda,
Dick Thomas
Publication year - 2001
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2001.tb10718.x
Subject(s) - mycobacterium smegmatis , dormancy , metronidazole , biology , mutant , microbiology and biotechnology , anoxic waters , bacillus (shape) , bacilli , bacteria , mycobacterium tuberculosis , antibiotics , biochemistry , botany , genetics , germination , gene , ecology , medicine , tuberculosis , pathology
Mycobacterium smegmatis is an obligate aerobe. However, growth analyses in oxygen‐limited liquid cultures have shown that the bacillus is able to survive anoxia with a half‐life of 4 days by shifting down to a drug‐resistant, dormant state. Metronidazole is the first lead against dormant bacilli and shows selective toxicity for this physiological state. Here, we report a plate‐based dormancy culture system employing anoxic jars for M. smegmatis . Its usefulness for the genetic analysis of dormancy was demonstrated by isolating the first metronidazole‐resistant mutants. Highly resistant mutants formed slightly yellow (as opposed to creamy) colonies. Furthermore, high‐level metronidazole resistance correlated with an increased half‐life of 12 days under anoxic conditions. This suggests a link between metronidazole susceptibility and anaerobic survival.