Comparative in-vitro activities of ten fluoroquinolones and fusidic acid against Mycobacterium spp.

The in-vitro activities of eight new quinolones (A-56620, amifloxacin, difloxacin, CI-934, enoxacin, irloxacin, pefloxacin, temafloxacin), two reference fluoroquinolones (ciprofloxacin and ofloxacin) and fusidic acid against 147 mycobacterial strains, belonging to seven different species, were compared. Temafloxacin, ofloxacin and ciprofloxacin were the most active compounds. They only showed consistent activity against Mycobacterium tuberculosis, M. malmoense and M. fortuitum, but not against M. chelonei, M. avium, M. intracellulare and M. scrofulaceum. However, individual strains of these species were sometimes susceptible. The best overall in-vitro activity was obtained with temafloxacin, which often showed activity where other products were inactive. Fusidic acid merely displayed good activity against M. tuberculosis (MIC90 16 mg/l).