• Vol. 36 No. 6, 379–383
  • 15 June 2007

Predictors of Vancomycin-resistant Enterococcus (VRE) Carriage in the First Major VRE Outbreak in Singapore



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Introduction: Until recently, vancomycin-resistant enterococcus (VRE) infection or colonisation was a rare occurrence in Singapore. The first major VRE outbreak involving a 1500-bed tertiary care institution in March 2005 presented major challenges in infection control and came at high costs. This study evaluates the predictors of VRE carriage based on patients’ clinical and demographic profiles. Materials and Methods: Study patients were selected from the hospital inpatient census population during the VRE outbreak (aged 16 years or more). Clinical information from 84 cases and 377 controls were analysed. Results: Significant predictors of VRE carriage included: age >65 years [Odds ratio (OR), 1.98; 95% CI (confidence interval), 1.14 to 3.43); female gender (OR, 2.15; 95% CI, 1.27 to 3.65); history of diabetes mellitus (OR, 1.94; 95% CI, 1.14 to 3.30), and staying in a crowded communal ward (OR, 2.75; 95% CI, 1.60 to 4.74). Each additional day of recent hospital stay also posed increased risk (OR, 1.03; 95% CI, 1.01 to 1.04). Conclusion: Elderly diabetic females with prolonged hospitalisation in crowded communal wards formed the profile that significantly predicted VRE carriage in this major hospital-wide outbreak of VRE in Singapore. It is imperative that active VRE surveillance and appropriate infection control measures be maintained in these wards to prevent future VRE outbreaks.

Vancomycin-resistant enterococci (VRE) have emerged as one of the most challenging nosocomial threats in the past decade globally.1,2 Although antibiotic exposure may facilitate VRE transmission by providing selective advantage for VRE and increasing the concentration of VRE in the stools, antibiotic use in association with de novo development of VRE is thought to be unlikely or impossible, since spontaneous vancomycin-resistance mutations have not been observed.3 Interventions focused on preventing horizontal transmission are reported to have a greater impact in controlling the spread of VRE compared to efforts to improve antibiotic use, even if it is endemic, has a high prevalence, and is polyclonal.3-5

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