Resistance pattern of enterococcal isolates, phenotypic characterization of vancomycin resistant isolates from various clinical samples in a tertiary care hospital

Abstract

Introduction: Enterococci cause a multitude of infections and emergence of vancomycin resistance is of special concern, as it is the primary alternative drug to penicillin for treating Enterococcal infections. Objectives: The present study was taken up to know the species predominance, resistance pattern and various phenotypes of vancomycin resistant Enterococci in a tertiary care hospital in south India. Material & Methods: The Data collected from the department of Microbiology at Krishna Institute of Medical Sciences, Secunderabad from January 2012 to December 2015 was retrospectively analysed. 226 Enterococci were speciated, antibiograms were analyzed and phenotyping of VRE was done based on standard guidelines. Results & discussion: The predominant species was found to be E. faecalis (51.3%) followed by E. faecium (43.3%), E. gallinarum (2.2%), E. durans (1.32%), E. casseliflavus (0.88%) and E. raffinosus (0.88). E. faecalis showed less resistance (30.39%) to antimicrobials than E. faecium (50.64%). The resistance pattern was less in out-patient samples when compared to in-patient samples. Vancomycin resistant Enterococci were 13(5.75%), all isolated from inpatients. Among the 13 isolates, 6(46.15%) were VanA, 4(30.76%) were VanB and 3(23.07%) were VanC phenotypes. VanC phenotype was observed in E. casseliflavus and E. gallinarum due to intrinsic resistance. Conclusion: The species predominance of E. faecalis and E. faecium reflects the change in recent decade. Drug resistance pattern and phenotyping is correlating with other studies, VanA being the commonest. Monitoring for vancomycin resistant Enterococci is critical in hospital infection control and for effective treatment. Keywords: phenotyping; antibiogram; vancomycin-resistant Enterococci; infection control