title: Susceptibilities of genital mycoplasmas to the newer quinolones as determined by the agar dilution method.
abstract: The increasing resistance of genital mycoplasmas to tetracycline poses a problem because tetracycline is one of the few antimicrobial agents active against Mycoplasma hominis, Ureaplasma urealyticum, chlamydiae, gonococci, and other agents of genitourinary-tract disease. Since the quinolones are a promising group of antimicrobial agents, the susceptibilities of M. hominis and U. urealyticum to the newer 6-fluoroquinolones were determined by the agar dilution method. Ciprofloxacin, difloxacin, and ofloxacin had good activity against M. hominis, with the MIC for 50% of isolates tested (MIC50) being 1 microgram/ml. Fleroxacin, lomefloxacin, pefloxacin, and rosoxacin had MIC50s of 2 micrograms/ml. Enoxacin, norfloxacin, and amifloxacin had MIC50s of 8 to 16 micrograms/ml, and cinoxacin and nalidixic acid were inactive (MIC50, greater than or equal to 256 micrograms/ml). Overall, the activities of 6-fluoroquinolones for ureaplasmas were similar to those for M. hominis, with MICs being the same or twofold greater. The most active 6-fluoroquinolones against ureaplasmas were difloxacin, ofloxacin, and pefloxacin, with MIC50s of 1 to 2 micrograms/ml. Ciprofloxacin was unusual in that the MIC50 for M. hominis was 1 microgram/ml, whereas the MIC50 for ureaplasmas was 8 micrograms/ml. Since the MIC50s for the most active quinolones approximate achievable concentrations in blood and urine, quinolones have promise in treating mycoplasmal infections.
authors.affiliation: Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195.
authors.forename: G E
authors.initials: GE
authors.lastname: Kenny
authors.forename: T M
authors.initials: TM
authors.lastname: Hooton
authors.forename: M C
authors.initials: MC
authors.lastname: Roberts
authors.forename: F D
authors.initials: FD
authors.lastname: Cartwright
authors.forename: J
authors.initials: J
authors.lastname: Hoyt
mesh_terms: D042462:4-Quinolones; D000890:Anti-Infective Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D008826:Microbial Sensitivity Tests; D009174:Mycoplasma / Q000187:drug effects*; D014509:Ureaplasma / Q000187:drug effects*; D014566:Urogenital System / Q000382:microbiology
chemical_list: D042462:4-Quinolones; D000890:Anti-Infective Agents