Survey on antimicrobial resistance and virulence-related genes in Enterococcus faecium and Enterococcus faecalis collected from hospital environment in the north of Iran

Environmental contaminants in hospital settings play a major role in the spreading of pathogenic bacteria during outbreaks. The aim of this study was to evaluate the antibiotic resistance and virulence-related genes among Enterococcus strains isolated from hospital environment. Throughout this cross-sectional work, 388 samples were collected from hospital environment. Totally, 88 Enterococcus positive strains were characterized with diagnostic and confirmatory tests. Antibiogram was done according to the CLSI guideline. Genes encoding antibiotic resistance and virulence factors were detected by multiplex PCR. Out of 90 tested isolates, 53.33% and 46.6% of them were identified as E. faecium and E. faecalis, respectively. Also, multidrug resistance phenotype observed in 66.6% and 37.5% of E. faecalis and E. faecium strains, respectively. Distribution of resistance genes was as follows: ermB (66.6%), tetM and tetL (60%), aac(6′)-Ie-aph(2″)-Ia (28.8%), aph (3′)-IIIa (26.6%), and vanA, vanB (8.8%). Moreover, 97.7% and 17.7% of the isolates, carried virulence factors of esp and ace, respectively. This report showed that the environmental Enterococcus are the major sources of resistance genes that can transfer them to the clinical isolates of bacteria in hospital settings.