In vitro activity of new rifamycins against rifampicin-resistant M. tuberculosis and MAIS-complex mycobacteria.
Comparisons were made of the in vitro activity of rifampicin, and the rifamycin derivatives, rifapentine, rifabutin, CGP 29861, CGP 7040 and CGP 27557, against rifampicin-sensitive and rifampicin-resistant strains of Mycobacterium tuberculosis and against the Mycobacterium avium/intracellulare/scrofulaceum (MAIS) complex. The new rifamycins had MICs four to eight times lower than those of rifampicin against sensitive M. tuberculosis strains. Of the 35 rifampicin-resistant strains of M. tuberculosis, 31% were sensitive to rifabutin but only 3-11% to the other rifamycins. The proportions of the MAIS strains found to be sensitive were 35% for rifampicin, 50-60% for CGP 27557, rifapentine and rifabutin and 85-92% for CGP 29861 and CGP 7040.
Dickinson
J M
JM
Department of Bacteriology, Royal Postgraduate Medical School, London.
Mitchison
D A
DA
D000995:Antitubercular Agents / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D008826:Microbial Sensitivity Tests; D009162:Mycobacterium avium / Q000187:drug effects*; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D017828:Rifabutin; D012293:Rifampin / Q000031:analogs & derivatives / Q000494:pharmacology; D012294:Rifamycins / Q000494:pharmacology*
D000995:Antitubercular Agents; D012294:Rifamycins; C055682:CGP 7040; C055683:CGP 27557; C055684:CGP 29861; D017828:Rifabutin; D012293:Rifampin; C018421:rifapentine