From 1999 to 2009, a total of 10,470 clinical enterococcal strains from patients in Rajavithi Hospital were isolated. Of these, 201 (1.9%) vancomycin-resistant enterococci (VRE) including 199 (99.0%) Enterococcus faecium and 2 (1.0%) Enterococcus faecalis were found. The incidence of VRE was 1.8% in 1999, 3.3% in 2000, 5.1% in 2001, 1.0% in 2002, 0.0% in 2003 and 2004, 1.1% in 2005, 4.7% in 2006, 1.9% in 2007, 2.2% in 2008 and 0.9% in 2009. Seventy-one VRE isolates were classified to VanA phenotype (69 VanA E. faecium and 2 VanA E. faecalis) and 130 were classified to VanB phenotype (VanB E. faecium). The rate of inpatient departments (IPD) associated VRE (199 (99.0%) VRE isolates) was significantly greater than the incidence of outpatient departments (OPD)-VRE (2 (1.0%) VRE isolates). VRE were found in medical (33.7%), ICUs (15.6%) and surgical (15.1%) wards. VRE were mostly found in urine, 64.2%, following in pus, blood, genital and sputum specimens, 21.9%, 9.0%, 3.5% and 1.4%, respectively. VRE, especially vancomycin resistant E. faecium, were multidrug-resistant (resistance to ampicillin, tetracycline, norfloxacin, ciprofloxacin, erythromycin and gentamicin). All strains of VRE were fully susceptible to linezolid.

Keywords: Vancomycin-resistant Enterococci, VRE, Enterococcus faecalis, Enterococcus faecium, Antimicrobial susceptibility
testing