Although the isolation and detection of fluoroquinolone-resistant Haemophilus influenzae and Moraxella catarrhalis has been a very rare occurrence, newer agents in the quinolone class must be evaluated to determine their comparative potencies and to develop in vitro testing methods. BMS284756 is an investigational desfluoro(6)-quinolone with a spectrum of activity most similar to recently introduced agents such as gatifloxacin and trovafloxacin. This compound was compared to levofloxacin, gatifloxacin, ciprofloxacin and moxifloxacin, as well as other orally administered antimicrobials against 1,872 H. influenzae and 810 M. catarrhalis isolates. Two Canadian H. influenzae strains had ciprofloxacin MICs elevated above the normal wild type susceptible MIC population (>0.06 mug/mL). All other strains of H. influnenzae and M catarrhalis were highly susceptible to the tested quinolones (MIC90, 0.016 less than or equal to 0.03 mug/mL). For the two H. influenzae isolates with elevated quinolone MICs the potency rank order was: gatifloxacin and BMS284756 (MICs, 0.25 and 1 mug/mL) > levofloxacin and moxifloxacin > ciprofloxacin (MICs, 0.5 and > 2 mug/mL). The comparison of Etest (AB BIODISK, Solna, Sweden) and disk diffusion results to the reference broth microdilution values produced acceptable intermethod accuracy when applied to BMS284756. This novel desfluoro compound possesses promising activity against fastidious Gram-negative respiratory tract pathogens and further clinical development is underway. (C) 2001 Elsevier Science Inc. All rights reserved.
