In Vitro Development of Resistance to Six Quinolones in <i>Streptococcus pneumoniae, Streptococcus pyogenes</i> , and <i>Staphylococcus aureus</i>

Abstract

Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus isolates were exposed to subinhibitory MICs of ciprofloxacin, sparfloxacin, gatifloxacin, moxifloxacin, clinafloxacin, and gemifloxacin during a 10-day period. Subculturing led to resistance development, regardless of the initial potencies of the quinolones. None of the quinolones was associated with a significantly slower rate of resistance development.