Epidemiology and Control of the First Reported Vancomycin-resistant Enterococcus Outbreak at a Tertiary-care Hospital in Bangkok, Thailand.

This retrospective study described the first reported vancomycin-resistant enterococci (VRE) outbreak from June 2013 through January 2014 at a tertiary-care hospital in Bangkok, Thailand. After the index case was detected in an 18-bed medical intermediate care unit, a number of interventions was implemented, including targeted active surveillance for VRE, strict contact precautions, enhanced standard precautions, dedicated units for VRE cases, extensive cleaning of the environment and the restricted use of antibiotics. VRE isolates were evaluated by polymerase chain reaction and random amplified polymorphic DNA (RAPD) testing. A prevalence case-control study was conducted. Among 3,699 culture samples from 2,671 patients screened, 74 patients (2.8%) had VRE. The positivity rate declined from 15.1% during week 1 to 8.2% during week 2 and then 1.4% during week 3. By weeks 4-9, the prevalences were 0-2.7%. However, the prevalence rose to 9.4% during week 10 and then subsequently declined. All VRE isolates were Enterococcus faecium and had the vanA gene. RAPD analysis revealed a single predominant clone. Multivariate analysis showed mechanical ventilation for ≥ 7 days was a predictive factor for VRE colonization [odds ratio (OR) 11.47; 95% confidence interval (CI): 1.75-75.35; p = 0.011]. This experience demonstrates VRE can easily spread and result in an outbreak in multiple-bed units. Active surveillance, early infection control interventions and rapid patient cohorting were important tools for control of this outbreak. Patients requiring mechanical ventilator for ≥ 7 days were at higher risk for VRE acquisition.