Comparison of the VITEK 2 system with the E-test for the determination of glycopeptide susceptibility of vanA and vanC positive enterococci

Abstract

The performance of the VITEK 2 System (bioMérieux) version 3.01 software was compared to that of the E-test (AB Biodisk, Solna, Sweden) for antibiotic susceptibility testing of 17 clinical isolates of vancomycin resistant enterococcus (VRE). Antibiotic Susceptibility Testing (AST) by VITEK 2 produced 10 minor (59%) errors, resulting in false phenotypes. Reporting of vancomycin resistance in enterococcal strains has enormous therapeutic and epidemiological consequences. Therefore, at laboratories using automated systems (e.g. VITEK 2) for routine microbiological susceptibility testing data must be confirmed by independent validated methods, e.g. E-test, or microdilution.