Prevalence of Virulence Factors and Drug Resistance in Clinical Isolates of Enterococci: A Study from North India

Abstract

Along with emergence of multidrug resistance, presence of several virulence factors in enterococci is an emerging concept. This study was undertaken to determine the prevalence of various virulence factors phenotypically and genotypically in enterococci and study their association with multidrug resistance. A total of 310 enterococcal isolates were studied, comprising 155 E. faecium and 155 E. faecalis. Antimicrobial susceptibility testing was done by disc diffusion and agar dilution method. Hemolysin, gelatinase, biofilm production, and haemagglutination were detected phenotypically and presence of virulence genes, namely, asa1, gelE, cylA, esp, and hyl, was detected by multiplex PCR. Of the total, 47.41% isolates were high level gentamicin resistant (HLGRE) and 7.09% were vancomycin resistant (VRE). All the virulence traits studied were found in varying proportions, with majority in E. faecalis (p > 0.05). Strong biofilm producers possessed either asa1 or gelE gene. gelE silent gene was detected in 41.37% (12/29). However, increase in resistance was associated with significant decrease in expression or acquisition of virulence genes. Further, acquisition of vancomycin resistance was the significant factor responsible for the loss of virulence traits. Though it is presumed that increased drug resistance correlates with increased virulence, acquisition of vancomycin resistance might be responsible for reduced expression of virulence traits to meet the “biological cost” relating to VRE.

Incidence and Antimicrobial Susceptibility of Enterococcal Infections in Tertiary Care Hospital

“…(2003) reported steadily increased prevalence of VRE from 17.4% to 29.6% (10 years study from Division of Infectious Diseases and Centre for Clinical epidemiology and biostastisitcs; Philadelphia, Pennsylvana) [5]. In our study, VRE was seen in approximately 2 %, which is much lesser when compared to other studies wherein VRE ranged from 4% to 23% [5,19,[25][26][27]. All E.fecalis, E. gallinarum and E. avium were 100% sensitive to Teicoplanin.…”

Determination of Virulence Factors in Clinical Multidrug Resistance Enterococci Isolates at Southeast of Iran

“…Nevertheless, we found the distribution of this gene in 14.1% of all Enterococci, particularly E. faecalis (two isolates were related to MDRs) that associated with UTIs. Moreover, Banerjee et al represented cylA gene only in 5% of isolates whereas hemolysin production (in blood agar medium) was observed in 39% of isolates, that emphasizing the importance of testing virulence factors both phenotypically and genotypically (15).…”

Prevalence of Virulence Factors Among Enterococcal Isolates in a Tertiary Care Hospital

“…Biofilm production was observed in 32.5% of the enterococcal isolates in Giridhara Upadhyaya et al (28) study, which is similar to our findings. In Banerjee et al (29) study, haemolysin, gelatinase and biofilm formation was observed in 23.22%, 8.3% and 25.16% of the E. faecalis isolates and 40% 9.6% and 27.09% among E. faecium isolates.…”