Characterization of a Mycobacterium smegmatis Mutant That Is Simultaneously Resistant to d-Cycloserine and Vancomycin

A mutant of Mycobacterium smegmatis has been isolated that is simultaneously resistant to both d-cycloserine (d-CS) and vancomycin. Genetic complementation with a PBP4 homolog restores sensitivity to both drugs. Resistance to d-CS and vancomycin in this mutant is most likely due to a novel mechanism involving peptidoglycan assembly at the cell surface.