Comparative activity of cefditoren and other oral beta-lactams against nonpneumococcal streptococci

Background: In vitro studies of cefditoren activity have focused primarily on Streptococcus pneumoniae and other bacterial species isolated from patie nts with respiratory infections, but relatively few reports have been publi shed: describing the activity of cefditoren against clinical isolates of no npneumococcal streptococci. Methods: Cefditoren activity was determined by broth microdilution (M7-A5, NCCLS, 2000) for 450 viridans group streptococc i, 917 Streptococcus pyogenes and 800 other beta -hemolytic streptococci co llected throughout the US during 1999-2000. Results:Against viridans group streptococci, cefditoren (MIC90, 0.5 mug/ml) was 4-to 32-fold more active t han the other beta -lactams tested (penicillin ampicillin, amoxicillin-clav ulanate, cefprozil and cefuroxime). The difference in activity between cefd itoren and the other beta -lactams was greater for peniciltin-nonsusceptibl e isolates (MIC90s, 1 mug/ml versus 8-32 mug/ml) than among penicillin-susc eptible isolates (MIC90s, 0.12 versus 0.25-1 mug/ml). Cefditoren also demon strated potent activity against S. pyogenes (MIC90, 0.015 mug/ml) and other beta -hemolytic streptococci (MIC90, 0.06 mug/ml), comparable to that of t he other beta -lactams. Conclusions: The activity demonstrated by cefditore n against nonpneumococcal streptococci, including beta -lactam- and macroli de-resistant isolates, suggests that this agent holds promise as therapy fo r infections caused by all clinically significant species of streptococci. Copyright 2001 S. KargerAG, Basel.