Comparative antimycobacterial activities of difloxacin, temafloxacin, enoxacin, pefloxacin, reference fluoroquinolones, and a new macrolide, clarithromycin.

The activities of fluoroquinolones and a new macrolide against 30 clinical isolates of Mycobacterium tuberculosis were determined in vitro by agar diffusion. In order of relative potencies against M. tuberculosis, temafloxacin (MIC for 90% of isolates [MIC90], 2.3 micrograms/ml) was at least as active as the reference quinolones ofloxacin (MIC90, 2.4 micrograms/ml) and ciprofloxacin (MIC90, 4.3 micrograms/ml). Less active were difloxacin (MIC90, 4.7 micrograms/ml), pefloxacin (MIC90, 6.7 micrograms/ml), and enoxacin (MIC90, 8.3 micrograms/ml). The macrolide clarithromycin was more potent than erythromycin but less potent than the fluoroquinolones. Our results suggest that the newer fluoroquinolones and clarithromycin should be included with ciprofloxacin and ofloxacin in pharmacokinetic studies that may lead to trials in human subjects with mycobacterial infections.