title: Trends in gram-positive bloodstream organism resistance: a seven-year audit of five glycopeptides and other drugs at a large university hospital.
abstract: Gram-positive pathogens (n = 525) isolated from bloodstream infections were tested by a reference broth microdilution method to establish antibiotic susceptibility trends (1985 to 1991). Cefazolin, ciprofloxacin, gentamicin, novobiocin, oxacillin, rifampin, teicoplanin, vancomycin, trimethoprim/sulfamethoxazole, daptomycin and two investigational glycopeptides (LY264826 and MDL62873) were investigated. Strains were selected without bias (first two isolates each month/species; no patient duplicates) as follows: 132 Staphylococcus aureus, 129 Staphylococcus epidermidis, 72 Staphylococcus haemolyticus, 130 Enterococcus faecalis and 62 other enterococci. All isolates were susceptible to vancomycin and teicoplanin except for Staphylococcus haemolyticus which had a resistant teicoplanin MIC90 of 64 micrograms/mL. The susceptibilities to vancomycin and teicoplanin were unchanged over the monitored period. Daptomycin, LY264826 and MDL62873 also demonstrated consistent activity; MDL62873 being superior with a MIC90 of 0.12 micrograms/mL. In 1990-1991 a significantly increased resistance to ciprofloxacin was observed among oxacillin-resistant strains of staphylococci. Our data suggest that the emergence of invasive vancomycin-resistant strains in Gram-positive isolates remains a rare phenomenon. However, we have experienced an emergence of numerous ciprofloxacin-resistant strains among staphylococci that precludes its empirical use at our institution.
authors.affiliation: Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
authors.forename: J
authors.initials: J
authors.lastname: Ena
authors.forename: A
authors.initials: A
authors.lastname: Houston
authors.forename: R P
authors.initials: RP
authors.lastname: Wenzel
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D002939:Ciprofloxacin / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification; D006785:Hospitals, University; D006801:Humans; D007769:Lactams; D008826:Microbial Sensitivity Tests; D012310:Ristocetin / Q000031:analogs & derivatives; D013210:Staphylococcus / Q000187:drug effects* / Q000302:isolation & purification; D013997:Time Factors; D014640:Vancomycin / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D007769:Lactams; C057893:chloroorienticin A; C068029:MDL 62873; D012310:Ristocetin; D002939:Ciprofloxacin; D014640:Vancomycin