title: Prevalence and characteristics of ESBL-producing E. coli in Dutch recreational waters influenced by wastewater treatment plants.
abstract: Outside health care settings, people may acquire ESBL-producing bacteria through different exposure routes, including contact with human or animal carriers or consumption of contaminated food. However, contact with faecally contaminated surface water may also represent a possible exposure route. The current study investigated the prevalence and characteristics of ESBL-producing Escherichia coli in four Dutch recreational waters and the possible role of nearby waste water treatment plants (WWTP) as contamination source. Isolates from recreational waters were compared with isolates from WWTP effluents, from surface water upstream of the WWTPs, at WWTP discharge points, and in connecting water bodies not influenced by the studied WWTPs. ESBL-producing E. coli were detected in all four recreational waters, with an average concentration of 1.3 colony forming units/100ml, and in 62% of all samples. In surface waters not influenced by the studied WWTPs, ESBL-producing E. coli were detected in similar concentrations, indicating the existence of additional ESBL-E. coli contamination sources. Isolates with identical ESBL-genes, phylogenetic background, antibiotic resistance profiles, and sequence type, were obtained from effluent and different surface water sites in the same watershed, on the same day; occasionally this included isolates from recreational waters. Recreational waters were identified as a potential exposure source of ESBL-producing E. coli. WWTPs were shown to contribute to the presence of these bacteria in surface waters, but other (yet unidentified) sources likely co-contribute.
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands. Electronic address: hetty.blaak@rivm.nl.
authors.forename: Hetty
authors.initials: H
authors.lastname: Blaak
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Patrick
authors.initials: P
authors.lastname: de Kruijf
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Raditijo A
authors.initials: RA
authors.lastname: Hamidjaja
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Angela H A M
authors.initials: AH
authors.lastname: van Hoek
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands; Institute for Risk Assessment Sciences, Utrecht University, PO Box 80178, 3508 TD Utrecht, The Netherlands.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: de Roda Husman
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Zoonoses and Environmental Microbiology, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Franciska M
authors.initials: FM
authors.lastname: Schets
mesh_terms: D000818:Animals; D003114:Colony-Forming Units Assay; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D005618:Fresh Water / Q000382:microbiology*; D006801:Humans; D009426:Netherlands; D010802:Phylogeny; D015995:Prevalence; D062065:Wastewater / Q000382:microbiology; D018508:Water Purification / Q000379:methods / Q000706:statistics & numerical data; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D062065:Wastewater; D001618:beta-Lactamases
keywords: E. coli; ESBL; Recreational water; Wastewater treatment plants