The prevalence of fluoroquinolone resistance among clinically significant respiratory tract isolates of Streptococcus pneumoniae in the United Statesand Canada - 1997 results from the SENTRY Antimicrobial Surveillance Program

As part of the SENTRY antimicrobial resistance surveillance program, a tota l of 1100 clinically significant respiratory tract isolates of Streptococcu s pneumoniae were tested for susceptibility to six fluoroquinolone antimicr obial agents: ciprofloxacin, levofloxacin, , gatifloxacin, grepafloxacin, s parfloxacin, and trovafloxacin. Isolates were obtained during the 5-month p eriod, February to June, 1997 from 27 United States medical miter laborator ies and seven laboratories in Canadian health cave institutions. All testin g was performed in a single center. Of 1100 test strains, 3 (0.3%), all fro m different U.S. centers, were fluoroquinolone resistant. Among the remaini ng 1097 fluoroquinolone-susceptible isolates, the rank order of activity am ong the six agents tested in this study was grepafloxacin (modal MIC = 0.25 mu g/mL) = trovafloxacin (modal MIC = 0.25 mu g/mL) = sparfloxacin (0.25 m u g/mL) > gatifloxacin (0.5 mu g/mL) > levofloxacin (1 mu g/mL) = ciproflox acin (1 mu g/mL). Fluoroquinolone resistance is currently uncommon among re spir spiratory tract isolates of S. pneumoniae in North America, brit there exist clear differences between the in vitro activities of different fluor oquinolones for this organism. (C) 1998 Elsevier Science Inc.