title: Cultivation of Neisseria gonorrhoeae in liquid media and determination of its in vitro susceptibilities to quinolones.
abstract: The cultivation of Neisseria gonorrhoeae by use of fastidious broth (FB) was evaluated. FB was found to be able to support the growth of all N. gonorrhoeae strains tested in this study without a rapid decrease in the viable count after exponential growth. After 24 h of incubation at 35 degrees C with 5% CO(2), viable counts of all strains reached over 10(8) CFU/ml in FB. Similar growth of the wild-type strain and its target-altered quinolone-resistant derivatives was observed. The susceptibilities of laboratory-adapted strains and clinical isolates to quinolones were tested by the microdilution method using FB. The MICs determined by microdilution were not significantly different from those determined by the agar dilution method recommended by the CLSI (formerly National Committee for Clinical Laboratory Standards). Moreover, the concentration-dependent time-kill of quinolones such as gatifloxacin and ciprofloxacin was observed in FB. At 2 to 4 times the MIC, gatifloxacin and ciprofloxacin were predominantly bactericidal against N. gonorrhoeae WHO A. At the MIC, the activities of both quinolones ranged from bactericidal to bacteriostatic. At 0.25 to 0.5 times the MIC, gonococcal growth was comparable to that of the growth control. These results suggest that the cultivation of N. gonorrhoeae by use of FB may be useful for evaluation of the antibacterial effects of quinolones.
authors.affiliation: Department of Urology, Gifu University School of Medicine, Japan. masaya.takei@mb.kyorin-pharm.co.jp
authors.forename: Masaya
authors.initials: M
authors.lastname: Takei
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Fukuda
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yasuda
authors.forename: Takashi
authors.initials: T
authors.lastname: Deguchi
mesh_terms: D000890:Anti-Infective Agents / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D001431:Bacteriological Techniques; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D024841:Fluoroquinolones / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D008826:Microbial Sensitivity Tests; D008954:Models, Biological; D009344:Neisseria gonorrhoeae / Q000187:drug effects* / Q000254:growth & development*; D015363:Quinolones / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000890:Anti-Infective Agents; D003470:Culture Media; D024841:Fluoroquinolones; D015363:Quinolones