title: In-vitro selection of bacteria resistant to the 4-quinolone agents.
abstract: The activity of five 4-quinolone agents: norfloxacin, ciprofloxacin, ofloxacin, enoxacin and pefloxacin was tested against 121 distinct clinical bacterial isolates. Ciprofloxacin was the most active agent against Gram-negative bacteria and streptococci and pefloxacin was the most active against staphylococci. By serial sub-culture in sub-inhibitory concentrations of antibiotic we were able to select resistance in almost all Gram-positive and Gram-negative species, with the exception of Escherichia coli. Resistance to norfloxacin was more readily produced than resistance to the other four agents. There was almost complete cross-resistance among the five agents tested. The proportional increases in MIC were higher in Gram-negative than in Gram-positive organisms.
authors.forename: D I
authors.initials: DI
authors.lastname: Limb
authors.forename: D J
authors.initials: DJ
authors.lastname: Dabbs
authors.forename: R C
authors.initials: RC
authors.lastname: Spencer
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D015365:Enoxacin; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D009287:Naphthyridines / Q000494:pharmacology; D009643:Norfloxacin / Q000031:analogs & derivatives / Q000494:pharmacology; D015242:Ofloxacin; D010078:Oxazines / Q000494:pharmacology; D015366:Pefloxacin; D013210:Staphylococcus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D009287:Naphthyridines; D010078:Oxazines; D015366:Pefloxacin; D015365:Enoxacin; D002939:Ciprofloxacin; D015242:Ofloxacin; D009643:Norfloxacin