Species prevalence, antimicrobial susceptibility and detection of virulence factors of enterococci isolated from tertiary care hospital

Abstract

Introduction: Emergence of multidrug resistant nosocomial enterococcus strains emphasizes the need for further investigating enterococci. Objectives: To characterize enterococci from various clinical specimens, to determine the antimicrobial susceptibility pattern and to explore the association between virulence factors and antimicrobial resistance. Material and Methods: Two hundred and eighty three clinical isolates of enterococcus were speciated and subjected to antimicrobial susceptibility testing using Kirby Bauer disc diffusion method. They were screened for vancomycin resistance by vancomycin screening agar method as recommended by Clinical Laboratory Standards Institute 2014, and confirmed by determination of minimum inhibitory concentration using agar dilution and E test. Genotypic confirmation was done by polymerase chain reaction. Virulence factors (haemolysin, gelatinase and biofilm production) were detected phenotypically. Results: Of the 283 enterococci isolated, 12 species were identified; predominant species was Enterococcus faecalis (82.33%). High level gentamicin resistance (HLGR) and vancomycin resistance were observed among 55.57% and 6.01% of Enterococcus isolates respectively. All vancomycin resistant enterococci (VRE) were Enterococcus faecalis and had vanA phenotype and genotype. Sensitivity to linezolid was 100 per cent among enterococci. Hemolysin, gelatinase and biofilm production were seen in 15.90%, 12.36% and 13.43% of enterococcal isolates respectively.