Comparative in vitro antimicrobial activities of the newly synthesized quinolone HSR-903, sitafloxacin (DU-6859a), gatifloxacin (AM-1155), and levofloxacin against Mycobacterium tuberculosis and Mycobacterium avium complex

We compared the in vitro antimycobacterial activity of a new fluoroquinolon e, HSR-903, with strong activity against gram-positive cocci with those of levofloxacin (LVFX), sitafloxacin (STFX), and gatifloxacin (GFLX). The MICs of the quinolones for Mycobacterium tuberculosis and Mycobacterium avium c omplex were in the order STFX approximate to GFLX < LVFX less than or equal to HSR-903 and STFX less than or equal to GFLX less than or equal to HSR-9 03 less than or equal to LVFX, respectively. HSR-903 effectively eliminated intramacrophagial M. tuberculosis, as did LVFX, and exhibited bacteriostat ic effects against M. tuberculosis replicating in type II alveolar cells.