[Antibacterial activity in vitro of 10 quinolones against 20 strains of Legionella pneumophila].

Minimal inhibitory concentrations (MICs) of 10 quinolones were determined by dilution method on BCYE, for 20 strains of Legionella pneumophila. Since the BCYE Agar medium reduces the antibacterial activity of some antimicrobials, a correction factor was calculated. It was found to be 1 to 16 according to the antibiotic tested. The following mode adjusted MIC show the good in vitro antibacterial activity of quinolones on L. pneumophila: ofloxacin, pefloxacin, ciprofloxacin, norfloxacin, A 56620 cMIC: 0.06 microgram/ml), A 56619, enoxacin (cMIC: 0.12 microgram/ml), rosoxacin (cMIC: 0.25 microgram/ml). Pipemidic acid (cMIC: 2 micrograms/ml) and nalidixic acid (cMIC: 1 microgram/ml) were the least active.