Comparison of in vitro antimicrobial activities of ofloxacin, levofloxacin, ciprofloxacin, and sparfloxacin against various mycobacteria

In vitro antimicrobial activities of ofloxacin (OFLX), levofloxacin (LVFX), ciprofloxacin (CPFX), and sparfloxacin (SPFX) were compared against various mycobacteria using the agar dilution method with 7H11 medium, and the following results were obtained. (1) These four new quinolones showed excellent antimicrobial activities against M. tuberculosis, M. kansasii, and M. fortuitum. (2) SPFX was most active against slowly growing mycobacteria. The activity against M. tuberculosis was in the order of SPFX > CPFX > LVFX > OFLX. The activity against M. kansasii was in the order of SPFX > LVFX > OFLX > or = CPFX. (3) On the other hand, CPFX was most active against rapidly growing mycobacteria. The activity against M. fortuitum was in the order of CPFX > SPFX > LVFX > OFLX. Considering the in vitro antimicrobial activities and the pharmacokinetics of these four drugs, they could achieve favorable clinical outcomes for all the patients with pulmonary infection due to M. tuberculosis or M. fortuitum and some of the patients with pulmonary infection due to M. kansasii or M. chelonae.