Prevalence and Characterization of Invasive Isolates of Streptococcus Pyogenes with Reduced Susceptibility to Fluoroquinolones

Fluoroquinolone susceptibility testing was performed on invasive group A streptococcus isolates from 1992-1993 and 2003 from Ontario, Canada. None were nonsusceptible to levofloxacin. Two of 153 (1.3%) from 1992-1993 and 7 of 160 (4.4%) from 2003 had a levofloxacin MIC of 2 mu g/ml; all nine had parC mutations, and eight were serotype M6.