Open AccessNine-Hospital Study Comparing Broth Microdilution and Etest Method Results for Vancomycin and Daptomycin against Methicillin-Resistant Staphylococcus aureus
Author(s) -
Hélio S. Sader,
Paul R. Rhomberg,
Ronald N. Jones
Publication year - 2009
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.00093-09
Subject(s) - etest , daptomycin , broth microdilution , staphylococcus aureus , microbiology and biotechnology , vancomycin , methicillin resistant staphylococcus aureus , medicine , serial dilution , micrococcaceae , minimum inhibitory concentration , antibacterial agent , biology , antibiotics , bacteria , genetics , alternative medicine , pathology
Vancomycin and daptomycin MIC results for 1,800 randomly selected oxacillin (methicillin [meticillin])-resistantStaphylococcus aureus (MRSA) bloodstream isolates from nine U.S. hospitals (collected from 2002 to 2006) were determined by a reference broth microdilution (BMD) method using frozen-form panels with precise incremental dilutions and by the Etest technique. The Etest provided vancomycin and daptomycin MIC results that were consistently higher (0.5 to 1.5 log2 dilution steps) than those provided by the reference BMD method. The dominant MRSA population (91.2% of MRSA isolates) would be categorized as vancomycin nonsusceptible by the MIC results from the Etest method if the susceptibility breakpoint was adjusted downward to ≤1 μg/ml, as suggested by clinical outcome studies.