Comparative in vitro activities of several new fluoroquinolones and beta-lactam antimicrobial agents against community isolates of Streptococcus pneumoniae.

The in vitro susceptibilities of 551 community isolates of Streptococcus pneumoniae from the Canadian province of Ontario to several new fluoroquinolones and beta-lactam antimicrobial agents were determined by a broth microdilution technique. Eight (1.5%) of these isolates were moderately susceptible (MICs, greater than or equal to 0.12 and less than or equal to 1.0 microgram/ml) to penicillin; none was resistant. Temafloxacin, ciprofloxacin, and ofloxacin (MICs for 90% of strains tested, between 1 and 2 micrograms/ml) were the most active fluoroquinolones tested, and BMY-28100 (MIC for 90% of strains tested, 0.25 microgram/ml) was the most active of the new beta-lactams tested.