Comparative in vitro activity of gemifloxacin, ciprofloxacin, levofloxacinand ofloxacin in a North American surveillance study

The in vitro activity of gemifloxacin, a new fluoroquinolone, was compared to three marketed fluoroquinolones; ciprofloxacin, levofloxacin and ofloxac in against over 4,000 recent clinical isolates covering 29 species isolated in the United States and Canada between 1997-1999. Based on MIC(90)s, gemi floxacin was the most potent fluoroquinolone tested against a majority of G ram-positive isolates: Streptococcus pneumoniae, penicillin resistant S. pn eumoniae, macrolide resistant S. pneumoniae, ciprofloxacin non-susceptible (MIC greater than or equal to4 mug/mL) S. pneumoniae, S. pyogenes, S, agala ctiae, viridans streptococci, Enterococcus faecalis, methicillin susceptibl e Staphylococcus aureus, methicillin resistant S. aureus, S. epidermidis, S . hemolyticus, and S. saprophyticus. Against Enterobacteriaceae and aerobic non-Enterobacteriaceae Gram-negatives, gemifloxacin was usually comparable to ciprofloxacin and levofloxacin and more potent than ofloxacin for the f ollowing species: Citrobacter freundii, Enterobacter aerogenes, E, cloacae, Escherichia coli, Klebsiella oxytoca Klebsiella pneumoniae, Morganella mor ganii, Proteus mirabilis, P. vulgaris, Providencia stuartii, Serratia marce scens, Acinetobacter lwoffii, A. baumannii, Burkholderia cepacia, Haemophil us influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aerugi nosa, and Stenotrophomonas maltophilia. Gemifloxacin was generally 16-64 fo ld more potent than the other fluoroquinolones tested against Gram-positive Organisms and retains excellent activity comparable with ciprofloxacin and levofloxacin against a majority of Gram-negative pathogens. (C) 2001 Elsev ier Science Inc. All rights reserved.