title: Comparison of teicoplanin and vancomycin in vitro activity on clinical isolates of Staphylococcus aureus.
abstract: Ninety-one clinical isolates of Staphylococcus aureus have been tested with the Kirby Bauer and the Etest® method to determine the susceptibility to glycopeptides in the 2007-2010 period. Five strains (5.5%) were resistant to vancomycin and nine (9.9%) to teicoplanin. Teicoplanin showed a median minimal inhibitory concentration (MIC) of 1 mg/l (range 0.125-24 mg/l), an MIC50 of 1 mg/l, and an MIC90 of 2 mg/l; vancomycin had a median MIC of 1.5 mg/l (range 0.38-4 mg/l), an MIC50 of 1.5 mg/l, and an MIC90 of 2 mg/l. More isolates were distributed on higher values of MIC for vancomycin. Inhibition halos induced by vancomycin-impregnated paper diskettes were slightly larger than those by teicoplanin. Glycopeptide resistance among methicillin-resistant Staphylococcus aureus in Italy is an underestimated phenomenon, possibly due to the described underestimation of glycopeptides MICs by the automatic broth microdilution method, when compared to agar MIC assays. A teicoplanin MIC creep, as reported for vancomycin, cannot be assumed.
authors.affiliation: U.O.C. Malattie Infettive, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Tascini
authors.forename: Sarah
authors.initials: S
authors.lastname: Flammini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Leonildi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ciullo
authors.forename: Enrico
authors.initials: E
authors.lastname: Tagliaferri
authors.forename: Francesco
authors.initials: F
authors.lastname: Menichetti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007558:Italy; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D017334:Teicoplanin / Q000494:pharmacology*; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D017334:Teicoplanin; D014640:Vancomycin