In vitro antibacterial activity of DU-6859a, a new fluoroquinolone.
The in vitro antibacterial activity of DU-6859a, a new fluoroquinolone, against a wide variety of clinical isolates was evaluated and compared with those of tosufloxacin, ofloxacin, ciprofloxacin, and sparfloxacin. DU-6859a showed potent broad-spectrum activity against gram-positive, gram-negative, and anaerobic bacteria, and its activity was greater than those of the control quinolones. By comparison of MICs at which 90% of strains are inhibited, DU-6859a had potent activity against bacteria resistant to the control quinolones. The time-killing curves of quinolones showed that the number of viable cells decreased rapidly during 2 to 4 of incubation, and regrowth was not seen even after 8 h incubation. At a concentration of four times the MIC, the frequencies of appearance of spontaneous mutants of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa resistant to DU-6859a were < or = 4.0 x 10(-9) to 1.9 x 10(-8). The 50% inhibitory concentrations of DU-6859a were 0.86 and 1.05 micrograms/ml for the supercoiling activities of DNA gyrases isolated from E. coli and P. aeruginosa, respectively. The rank order of the 50% inhibitory concentrations observed for both DNA gyrases roughly paralleled the MICs.
Nakane
T
T
Episome Institute, Gunma, Japan.
Iyobe
S
S
Sato
K
K
Mitsuhashi
S
S
D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001424:Bacterial Infections / Q000382:microbiology; D004352:Drug Resistance, Microbial / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D024841:Fluoroquinolones; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D015363:Quinolones / Q000494:pharmacology*; D013141:Spiro Compounds / Q000494:pharmacology*; D059005:Topoisomerase II Inhibitors
D000890:Anti-Infective Agents; D004791:Enzyme Inhibitors; D024841:Fluoroquinolones; D015363:Quinolones; D013141:Spiro Compounds; D059005:Topoisomerase II Inhibitors; C076246:sitafloxacin