UPDATE OF LOMEFLOXACIN IN-VITRO ACTIVITY AND SPECTRUM - A MULTICENTERTRIAL TESTING CONTEMPORARY PATHOGENS FOLLOWING FOOD-AND-DRUG-ADMINISTRATION VALIDATION GUIDELINES

The United States Food and Drug Administration recently recommended th at the antimicrobial product package insert (PPI) subsection on microb iology be annually validated with regard to the compound's spectrum an d potency. To address this request, a nine-laboratory trial was organi zed to test (two methods) lomefloxacin, a newer fluoroquinolone, and n ine comparison drugs against PPI-listed pathogens (1934 strains). A br oad geographic sampling (nine medical centers) was achieved, and lomef loxacin was determined to be active [minimum inhibitory concentration (MICs), less than or equal to 2 mu g/ml for greater than or equal to 9 0% of strains] for all PPI-listed species except Pseudomonas aeruginos a, Citrobacter freundii, and Providencia rettgeri (42%-87% inhibited). Comparison fluoroquinolones also had a similarly compromised spectrum of activity against these species. Additional organism species, inclu ding Neisseria gonorrhoeae, N. meningitidis, Salmonella enteriditis, a nd Shigella species, should be added to the lomefloxacin PPI (MIC(90)s , 0.03-0.25 mu g/ml) following data generated in this study. These in vitro results indicate that lomefloxacin remains active against the va st majority of clinically ''indicated'' species, and that it has a spe ctrum compatible with other marketed fluoroquinolones for these tested pathogens, monitored in 1994.