In vitro activity of quinupristin/dalfopristin against erythromycin-susceptible and erythromycin-resistant Streptococcus pneumoniae.
Minimal inhibitory concentrations (MICs) of quinupristin/dalfopristin, penicillin, erythromycin, and clindamycin were determined by a standard agar dilution method for 93 Streptococcus pneumoniae strains isolated from patients with invasive disease in Germany. Quinupristin/dalfopristin showed good activity against 32 penicillin-susceptible/erythromycin-susceptible strains (MIC90 0.5 mg/l; range 0.25-0.5 mg/l) and 31 penicillin-intermediate/erythromycin-susceptible strains (MIC90 0.5 mg/l; range 0.25-1 mg/l). Erythromycin-resistant strains (n=30) were slightly less susceptible (MIC90 1 mg/l; range 0.125-2 mg/l). Quinupristin/dalfopristin was bactericidal (99.9% killing) for all six strains investigated after 2 h at a concentration of 4 mg/l.
Reinert
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National Reference Center for Streptococci, Institute of Medical Microbiology, University Hospital (RWTH) Aachen, Germany. Reinert@RWTH-Aachen.de
Kresken
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M
Mechery
V
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Lemperle
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M
Lütticken
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D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002981:Clindamycin / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination / Q000494:pharmacology*; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D014769:Virginiamycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D010406:Penicillins; D014769:Virginiamycin; C062940:quinupristin-dalfopristin; D002981:Clindamycin; D004917:Erythromycin; D010400:Penicillin G