The in vitro antibacterial activity of gatifloxacin, a new quinolone antimicrobial agent

• Published in: Japanese Journal of Chemotherapy Vol. 47; no. Supplement2; pp. 3 - 11
• Main Authors: Yamamoto, Takao, Tomizawa, Hiroshi, Fukuda, Hideyuki, Hori, Shizuko, Hosaka, Masaki, Yasue, Tokutaro, Oomori, Yasuo
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Chemotherapy 1999; 公益社団法人 日本化学療法学会
• Subjects: gatifloxacin; in vitro抗菌力; 新キノロン系抗菌薬
• ISSN: 1340-7007; 1884-5886
• DOI: 10.11250/chemotherapy1995.47.Supplement2_3

The in vitro antibacterial activity of gatifloxacin (GFLX), a new fluoro-methoxy-quinolone agent, was studied and compared with that of other new quinolones. GFLX showed a broad spectrum of potent antibacterial activity against Gram-positive bacteria, Gram-negative bacteria, anaerobic bacteria, and Mycobacterium spp. The antibacterial activity of GFLX was superior to that of norfloxacin (NFLX), ciprofloxacin (CPFX), and levofloxacin (LVFX), and comparable to that of tosufloxacin (TFLX) and sparfloxacin (SPFX) against clinical isolates of Gram-positive bacteria, including Staphylococcus aureus subsp. aureus and Streptococcus pneumoniae. Against clinical isolates of Gram-negative bacteria, including the family Enterobacteriaceae and glucose-nonfermentative rods, GFLX possessed the same antibacterial activity as NFLX, SPFX, and LVFX, and only slightly lower activity than CPFX and TFLX. Against Haemophilus infiuenzae, the antibacterial activity of GFLX was superior to that of NFLX, CPFX, TFLX, and SPFX, and comparable to that of LVFX. GFLX showed higher antibacterial activity than CPFX and the same antibacterial activity as SPFX against clinical isolates of Mycoplasma pneumoniae and Ureaplasma urealyticum. The in vitro antibacterial activity of GFLX was not influenced by the type of medium, inoculum size, pH of medium, or addition of human serum or human urine. However, the activity of GFLX decreased in the presence of Mg++, similar to the decrease in activity of CPFX in the same condition.