In vitro activity of antimicrobial agents against oxacillin resistant staphylococci with special reference to Staphylococcus haemolyticus.
One hundred and sixty seven isolates of staphylococci isolated from the inpatients of a tertiary care referral hospital in South India were speciated and activity of oxacillin, glycopeptides, linezolid and quinupristin/dalfopristin against these isolates was tested by broth microdilution method. Of the 114 coagulase negative staphylococci (CoNS), 49.1 % were S. haemolyticus, isolated predominantly from urine (64.6%), while the rest belonged to 11 other species. More than half the isolates of S. aureus (52.8%) and 68.4% of the CoNS were oxacillin resistant. All the strains were uniformly susceptible to vancomycin, linezolid and quinupristin/dalfopristin; but 25.6% isolates of S. haemolyticus showed reduced susceptibility to teicoplanin (MIC: 8-16 mg/L). Our study demonstrates the high prevalence of oxacillin resistance among hospital isolates of S. aureus and CoNS in India. Vancomycin, along with the newer agents like linezolid and quinupristin/dalfopristin remains the drug of choice for treating multi drug resistant staphylococcal infections.
Chaudhury
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Department of Microbiology, SV University of Medical Sciences, Tirupati, Andhra Pradesh, India. abhijitch2001@yahoo.co.in
Kumar
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AG
D000081:Acetamides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D007194:India; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology*; D023303:Oxazolidinones / Q000494:pharmacology; D013210:Staphylococcus / Q000187:drug effects*; D041162:Staphylococcus haemolyticus / Q000187:drug effects*; D017334:Teicoplanin / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology; D014769:Virginiamycin / Q000031:analogs & derivatives / Q000494:pharmacology
D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D014769:Virginiamycin; C113825:quinupristin; D017334:Teicoplanin; D014640:Vancomycin; D000069349:Linezolid; C113826:dalfopristin; D010068:Oxacillin