[In vitro antimycobacterial activities of a new quinolone, balofloxacin]

Balofloxacin (BLFX), a newly developed fluoroquinolone, was studied for its in vitro antimycobacterial activity by the agar dilution method with 7H11 agar medium. The MIC90s were as follows: 0.39 microgram/ml for M. tuberculosis, > 50 micrograms/ml for M. avium, > 50 micrograms/ml for M. intracellulare, 0.39 microgram/ml for M. kansasii, 0.39 microgram/ml for M. fortuitum, > 50 micrograms/ml for M. abscessus, and 50 micrograms/ml for M. chelonae. The antimycobacterial activity of BLFX was comparable or slightly inferior to that of levofloxacin (LVFX). Considering the present findings and pharmacokinetics of BFLX, it appears that BFLX may achieve favorable outcome in the treatment of patients with infection due to M. tuberculosis, M. kansasii, or M. fortuitum similar to that of ofloxacin or LVFX.