title: Antimicrobial activity and interaction of pefloxacin and its principal metabolites. Collaborative Antimicrobial Susceptibility Testing Group.
abstract: The in vitro antimicrobial activity of pefloxacin and its major metabolites was determined and the interaction of pefloxacin and N-demethyl pefloxacin (norfloxacin) assessed at the ratio naturally occurring in urine (1:2). Pefloxacin and N-demethyl pefloxacin had approximately the same spectrum but were markedly more active than N-oxide pefloxacin (MIC90s greater than or equal to 64 micrograms/ml) against 867 stock strains. When combined with N-demethyl pefloxacin, pefloxacin had greater potency and a broader spectrum in tests against 5869 fresh clinical organisms. For approximately 10% more strains pefloxacin MICs were less than or equal to 2 micrograms/ml when pefloxacin was combined with 2 parts (4 micrograms/ml) of N-demethyl pefloxacin. The most significant extension of the pefloxacin spectrum was to include non-enteric gram-negative bacilli (inhibition of 67% versus 88%) and enterococci-streptococci (inhibition of 33% versus 86%). These results are similar to those previously noted for enoxacin plus 3-oxo-enoxacin, and potentially achievable with other newer fluoro-quinolones undergoing significant metabolism.
authors.affiliation: Clinical Microbiology Institute, Tualatin, Oregon 97062.
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
mesh_terms: D000900:Anti-Bacterial Agents; D001419:Bacteria / Q000187:drug effects*; D002939:Ciprofloxacin / Q000494:pharmacology; D004347:Drug Interactions; D004359:Drug Therapy, Combination / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D009643:Norfloxacin / Q000494:pharmacology*; D015366:Pefloxacin / Q000031:analogs & derivatives / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D015366:Pefloxacin; D002939:Ciprofloxacin; C060907:pefloxacin N-oxide; D009643:Norfloxacin