Phenotypic and genotypic detection of the virulence factors and their association with antibiotic resistance in Enterococcus species

Abstract- Along with the emergence of drug resistant Enterococcal infection, role of various virulence factors in Enterococci is an emerging concept. A number of virulence factors like biofilm formation, hemolysin production, gelatin hydrolysis have important role in the pathogenesis of Enterococci and also associated with antibiotic resistance. The aim of our study was to detect the virulence factors and their encoding genes (asa, gelE, esp, ebpR, hyl gene for biofilm; cylA gene for hemolysis; gelE gene for gelatin hydrolysis) and also observe their association with antimicrobial resistance Enterococci. A total of 87 Enterococci were collected from different clinical samples. Virulence factors were detected phenotypically and antibiotic sensivity were done by Kirby Bauer disc diffusion method. Virulence genes were detected by conventional multiplex PCR and only the ebpR gene was detected by single conventional PCR. Majority of the isolated Enterococci were E. faecalis (75%) followed by E. faecium (23%) and (2%) E. raffinosus were also detected. About 52.3% of E. faecalis and 35% of E. faecium isolates were biofilm producers. Significant association was found between biofilm formation and asa, esp, ebpR genes both in E. faecalis and in E. faecium. Hemolysis was observed phenotypically in 30.8% isolates of E. faecalis and 20% isolates of E. faecium. Significant association was observed between cylA gene and hemolysin production in E. faecalis. Antibiotic resistance were higher in biofilm and hemolysin producing isolates of both species. Resistance to some antibiotics including ampicillin, ciprofloxacin, gentamicin were significantly higher among biofilm and hemolysin producer in E. faecalis.