title: Virulence and antimicrobial resistance of Enterococcus faecium isolated from water samples.
abstract: The aim of this study was to determine the incidence of Enterococcus species and six virulence factors of Enterococcus faecium which were isolated from surface water and wells. Fifteen different water samples, which were used for drinking as well as agricultural irrigation, were collected from nine private wells and surface water from six rivers located at the east of Tehran. The Ent. faecium isolates were tested for their resistance to 10 antibiotics and their virulence factors were detected using multiplex PCR for esp, acm, gelE, asa1, cylA and hyl genes. The most predominant species in 315 isolates were Ent. faecium (n = 118) followed by Enterococcus galinarom (n = 110), Enterococcus mundeti (n = 18), Enterococcus hirea (n = 37) and Enterococcus casselifelavus (n = 32). The resistance rates were observed in 41·5, 27·1, 12·7, 6·8 and 1·7% isolates for tetracycline, erythromycin, ampicillin, ciprofloxacin and chloramphenicol respectively. None of the Ent. faecium isolates were resistant to vancomycin, teicoplanin, linezolid, gentamicin and quinuspristin-dalfopristin. Virulence determinant was found in 84·7, 33·9, 16·1 and 2·5% of isolates for acm, asa1, esp, cylA respectively. None of the isolates carried hyl and gelE gene. The presence of virulence factors and antibiotic resistance indicated that water might be an important source of dissemination of virulent enterococci.
  
  
  CONCLUSIONS
  Contamination of drinking or recreational water by human or animal faecal waste is a major public health threat. In this study, we determine the incidence of Enterococcus species and six virulence factors of Enterococcus faecium which were isolated from surface water and wells. Results from this study suggest that the presence of Ent. faecium in natural and well waters was found to be significant in rural areas of Tehran. Resistant to erythromycin among Ent. faecium was relatively high and the incidence of acm and asa1 among our isolates was common overall.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Enayati
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: J
authors.initials: J
authors.lastname: Sadeghi
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Nahaei
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Aghazadeh
authors.affiliation: Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Pourshafie
authors.affiliation: Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Talebi
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D060766:Drinking Water / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016984:Enterococcus faecium / Q000187:drug effects* / Q000302:isolation & purification; D004917:Erythromycin / Q000494:pharmacology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics; D014871:Water Microbiology; D060986:Water Wells
chemical_list: C473793:Acm protein, Enterococcus faecium; D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D060766:Drinking Water; D037521:Virulence Factors; D004917:Erythromycin
keywords: Enterococcus faecium; antibiotic resistance; faecal contamination; surface water; virulence factors