Detection of clinically relevant genotypes of vancomycinresistant enterococci in nosocomial surveillance specimens by PCR

This study evaluated a PCR method for the rapid detection of clinically significant genotypes of vancomycin-resistant enterococci (VRE) in nosocomial surveillance specimens. Detection of the vanA and vanB genes by mul-tiplex PCR using 657 specimens that showed presumptive growth of VRE on bile esculin azide agar containing 6 mg of vancomycin/liter was compared to the conventional method. The diagnostic values for the PCR com-pared to the phenotypic method were as follows: 99.8 % specificity, 95.4 % sensitivity, 98.8 % positive predictive value, and 99.3 % negative predictive value. The average cost per test for PCR is $8.26, compared to $9.45 for the phenotypic method. The average turnaround time for detecting a VRE is 48 h for PCR, compared to 96 h for the conventional method. Since the late 1980s vancomycin-resistant enterococci (VRE) have emerged as an important cause of nosocomial infections. They are the third most common cause of hospital-acquired bacteremia (5). Outbreaks with VRE are also being reported with increasing frequency in many countries (1). The National Nosocomial Infection Surveillance (NNIS) system in the Unit-ed States has reported an increase of VRE since 1989 (1)