A study on virulence factors and antimicrobial resistance pattern among enterococci isolated from various clinical specimens from a tertiary care hospital

摘要

Background: Enterococci, adult faeces commensal are important nosocomial pathogens . E. faecalis is the most common cause of infection, followed by E. faecium . In the past two decades, they have developed resistance to many commonly used antimicrobial agents. Understanding virulence factors and monitoring antimicrobial resistance among Enterococci is essential for controlling the spread of bacterial resistance and important for epidemiological surveillance within the hospital environment. The aim of the study is to evaluate antibiotic resistance and virulence factors exhibited by Enterococcus sp. Methods: One hundred consecutive isolates of Enterococci isolated from different clinical samples of patients attending AVMC and H, a tertiary care center at Pondicherry in a period of 20 months were included in the study. Enterococcus sp were identified as per standard conventional bacteriologic methods and detected for the production of virulence factors such as Hemolysin production, Gelatinase production. Antimicrobial susceptibility testing was carried out by disc diffusion method and MIC of vancomycin and teicoplanin was determined by E-test strips. Results: Among 100 Enterococcal isolates included in the study, 81% were E. faecalis and 19% were E. faecium which were isolated from urine (44%), Pus (51%) and others specimen (5%, which includes blood 80% and drain tube 20%). In this study, overall 15% of E. faecalis and 1% of E. faecium showed hemolysin production and Gelatinase was produced by 6% of E. faecalis and 4% of E. faecium . Majority of E. faecalis and E. faecium strains isolated in our study, had increased sensitivity were to be exhibited for Linezolid, Vancomycin followed by high level gentamycin and high degree of resistance to penicillin, ciprofloxacin and cotrimoxazole. Analyzing the results of MIC of vancomycin and teicoplanin, 5 isolates were classified phenotypically as VanB phenotype that possess only moderate to high levels of vancomycin resistance and one isolate obtained from drain tube which showed MIC of vancomycin as 120μg/ml and teicoplanin 16μg/ml was grouped into VanA. Conclusions: Though the prevalence of vancomycin resistant Enterococcci (VRE) is very low in our study, yet regular monitoring of vancomycin resistance is very crucial for early detection, treatment, application of preventive and control measures and most importantly to check the spread of virulent multidrug resistant Enterococcus species.