DIFFERENT RIFAMPICIN INACTIVATION MECHANISMS IN NOCARDIA AND RELATED TAXA

Mycolic acid-containing bacteria inactivate rifampicin in a variety of ways such as glucosylation, ribosylation, phosphorylation and decolor ization. These inactivations were found to be a species-specific pheno mena in Nocardia and related taxa. Gordona, Tsukamurella and fast-grow ing Mycobacterium modified rifampicin by ribosylation of the 23-OH gro up of the antibiotic. Such ribosylation was not observed in Rhodococcu s and Corynebacterium, but phosphorylation of the 21-OH group of rifam picin was observed in one strain of Rhodococcus. Nocardia modified the antibiotic by glucosylation (23-OH group) and phosphorylation, but ri bosylation was not observed.