Vancomycin Resistant Enterococci Infections in Trinidad and Tobago

Abstract

Aims: To document Vancomycin Resistant Enterococci (VRE) infections prevalence, risk factors, antimicrobial susceptibility patterns and evaluation of chromogenic plates in identifying VRE isolates in Trinidad and Tobago. Study Design: This was a cross sectional prospective observational and descriptive study. Place and Duration of Study: Study was carried out in all major regional hospitals in Trinidad & Tobago over a four year period, 2009 to 2013. Methodology: All cases of Enterococcus infections from major hospitals in the country were reviewed. Standardized questionnaire was used to analyze epidemiological and clinical data of VRE infected patients. Enterococcal speciation, minimum inhibitory concentrations (MIC) were evaluated using Microscan Walk Away 96SI (Siemens, USA). Isolates were further identified using 6.5% NaCl and pyrrolidonyl arylamidase activity according to CLSI guidelines. Brain Heart Infusion agar, Bile esculin azide agar containing 6 mg/L of vancomycin and chromogenic agar plates - Chromagar VRE and chrom ID VRE were used to screen and confirm VRE isolates Results: A low (3.9%) VRE infections were encountered from 1,141 enterococcal infections reviewed. Majority of these infections occurred in the surgical facilities (42%) and least from the burns unit (2%) respectively. No significant association was observed between VRE infections and patients’ gender, age, wards or hospital facilities. However underlying diseases such as diabetes mellitus and hypertension; and prior use of antibiotics on or before admission were noted to be associated with the VRE infections. All the VRE infections were mainly caused by E. faecium and E. faecalis that were completely (100%) resistant to ciprofloxacin, erythromycin, levofloxacin, rifampin and vancomycin, but were 95% and 100% susceptible to gentamycin and linezolid respectively. Overall, performance of the chromogenic agar plates were 100% sensitive and specific for VRE Conclusion: In Trinidad & Tobago VRE infections prevalence although low are strongly associated with high antibiotic consumption, prolonged hospitalization and diabetes mellitus disease. Linezolid is highly susceptible to multidrug resistant VRE isolates in the country. Chromogenic VRE media produced rapid and reliable identification of VRE organism. Further use of molecular studies to monitor the epidemiology of VRE infections in hospitals in the country is highly recommended.