A Study on the Prevalence of Vancomycin-resistant Enterococci and Their Antibiotic Resistance Pattern in Recreational Waters in Guilan Province, Iran

 Enterococcus faecalis (E. faecalis) is a major opportunistic pathogen that causes nosocomial infections in humans, especially in immunocompromised and elderly people. This bacterium can survive and grow in harsh conditions and low-nutrient environments, so it is usually found in water and can easily be transmitted via the fecal-oral route. Due to the high usage of antibiotics, many antibiotic-resistant strains of E. faecalis have been evolved, especially vancomycin-resistant ones (VRE). Water-borne VRE is an environmental and health problem. Since the monitoring of recreational waters is so important in human health, the aim of the present study was to investigate the prevalence of VRE isolates and their antibiotics patterns in the environmental samples from recreational waters in Guilan Province, Iran.

 The environmental samples were obtained from recreational waters in six cities in Guilan Province, North of Iran, 4 stations in Anzali wetland, and 5 main rivers entering Anzali wetland from January to September 2019. E. faecalis samples were identified by microscopic analysis, biochemical tests, and molecular identification. Antibiotic resistance patterns of the isolates were determined by an antibiogram test. The molecular identification of the isolates was performed using polymerase chain reaction (PCR) with specific primers for the ddlE gene.

Overall, in 268 samples, Enterococci were detected in 154 samples (57.46%), of which 35 isolates (29.68%) were VRE. From VRE isolates 32 isolates (91.42%) belonged to E. faecalis, 2 isolates (5.71%) belonged to E. faecium, and one isolate (2.86%) belonged to other Enterococcus species.

This study shows the high prevalence and antibiotic resistance rate of VRE strains of E. faecalis in water resources in Guilan province, which can be alarming and needs to be considered.