Vancomycin resistant enterococcal (VRE) colonization among patients treated in intensive care units at the National Hospital of Sri Lanka, and determination of genotype/s responsible for resistance

Abstract

The aim of this study was to assess the epidemiology of VRE colonization among patients in the intensive care units (ICU) of the National Hospital of Sri Lanka (NHSL). A cross sectional study was carried out on 218 patients admitted to 12 ICUs of the NHSL from January to March 2012. Rectal swabs were collected on day 0, 4, 8 and every 4th day thereafter till discharge. Enterococci were isolated on selective media and identified up to species level using standard bacteriological procedures. Standardized disc diffusion antibiotic susceptibility testing to ampicillin, teicoplanin and vancomycin was performed using the Clinical and Laboratory Standards Institute (CLSI) method. Minimum inhibitory concentrations to vancomycin were determined, using the E-test in strains showing intermediate or frank resistance to vancomycin by disc diffusion. Genotype determination (van A / van B) was carried out on isolates identified as VRE using the polymerase chain reaction. Patients positive for VRE colonization were followed up to discharge or death. VRE prevalence in the study sample was 5%. Univariate analysis showed that the use of metronidazole (odds ratio [OR] :15.73;95% 95% confidence interval [CI] : 3.94-62.67,P<0.05) or teicoplanin (OR: 12.56; 95% CI:2.65 – 59.52, p< 0.05) and diabetes (OR: 05.13; 95% CI: 1.36 – 18.7, p< 0.05) or hemodialysis during ICU stay (OR: 7.38 ;95% CI : 1.69-32.16, P<0.05) were associated with an increased risk of VRE colonization. The 5% prevalence of VRE colonization detected signals the emergence of VRE in the intensive care setting in Sri Lanka.