Detection and typing of vancomycin-resistance genes of enterococci from clinical and nosocomial surveillance specimens by multiplex PCR

<jats:p>Ninety-three clinical isolates of vancomycin-resistant enterococci (VRE) collected from nine hospitals in Taiwan were examined for the presence of <jats:italic>vanA</jats:italic>, <jats:italic>vanB</jats:italic>, <jats:italic>vanC1</jats:italic>, or <jats:italic>vanC2/vanC3</jats:italic> genes by a multiplex PCR. Forty-seven of these VRE isolates were <jats:italic>vanA</jats:italic> positive, 1 contained both <jats:italic>vanC1</jats:italic> and <jats:italic>vanA</jats:italic>, 40 harboured <jats:italic>vanB</jats:italic>, 2 were <jats:italic>vanC1</jats:italic>, and 3 were identified to be <jats:italic>vanC2/vanC3</jats:italic>. Twenty-four <jats:italic>vanA</jats:italic> isolates were sensitive to teicoplanin and thus did not have a typical VanA phenotype. Five isolates with the VanC phenotype harboured <jats:italic>vanB</jats:italic>. None of the 40 clinically isolated vancomycin-susceptible <jats:italic>E. faecium</jats:italic> or <jats:italic>E. faecalis</jats:italic> and the vancomycin-resistant <jats:italic>Leuconostoc</jats:italic> and <jats:italic>Pediococcus</jats:italic> isolates were positive for any of the <jats:italic>van</jats:italic> genes. While performing nosocomial surveillance, VRE were isolated from 47 of 467 rectal swabs by culture. Compared with the conventional culture method, the sensitivity and specificity of the multiplex PCR for detecting and identifying vancomycin-resistance genes in enterococci directly from culture-positive broth were 97·9% and 100%, respectively. The results suggest that genotypic characterization of vancomycin-resistance is necessary for all clinical VRE isolates and that the multiplex PCR assay can be an alternative method for this purpose.</jats:p>