title: Multidrug-Resistant and Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Dutch Surface Water and Wastewater.
abstract: OBJECTIVE
  The goal of the current study was to gain insight into the prevalence and concentrations of antimicrobial resistant (AMR) Escherichia coli in Dutch surface water, and to explore the role of wastewater as AMR contamination source.
  
  
  METHODS
  The prevalence of AMR E. coli was determined in 113 surface water samples obtained from 30 different water bodies, and in 33 wastewater samples obtained at five health care institutions (HCIs), seven municipal wastewater treatment plants (mWWTPs), and an airport WWTP. Overall, 846 surface water and 313 wastewater E. coli isolates were analysed with respect to susceptibility to eight antimicrobials (representing seven different classes): ampicillin, cefotaxime, tetracycline, ciprofloxacin, streptomycin, sulfamethoxazole, trimethoprim, and chloramphenicol.
  
  
  RESULTS
  Among surface water isolates, 26% were resistant to at least one class of antimicrobials, and 11% were multidrug-resistant (MDR). In wastewater, the proportions of AMR/MDR E. coli were 76%/62% at HCIs, 69%/19% at the airport WWTP, and 37%/27% and 31%/20% in mWWTP influents and effluents, respectively. Median concentrations of MDR E. coli were 2.2×10(2), 4.0×10(4), 1.8×10(7), and 4.1×10(7) cfu/l in surface water, WWTP effluents, WWTP influents and HCI wastewater, respectively. The different resistance types occurred with similar frequencies among E. coli from surface water and E. coli from municipal wastewater. By contrast, among E. coli from HCI wastewater, resistance to cefotaxime and resistance to ciprofloxacin were significantly overrepresented compared to E. coli from municipal wastewater and surface water. Most cefotaxime-resistant E. coliisolates produced ESBL. In two of the mWWTP, ESBL-producing variants were detected that were identical with respect to phylogenetic group, sequence type, AMR-profile, and ESBL-genotype to variants from HCI wastewater discharged onto the same sewer and sampled on the same day (A1/ST23/CTX-M-1, B23/ST131/CTX-M-15, D2/ST405/CTX-M-15).
  
  
  CONCLUSIONS
  In conclusion, our data show that MDR E. coli are omnipresent in Dutch surface water, and indicate that municipal wastewater significantly contributes to this occurrence.
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Hetty
authors.initials: H
authors.lastname: Blaak
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Gretta
authors.initials: G
authors.lastname: Lynch
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Ronald
authors.initials: R
authors.lastname: Italiaander
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Raditijo A
authors.initials: RA
authors.lastname: Hamidjaja
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Franciska M
authors.initials: FM
authors.lastname: Schets
authors.affiliation: Centre for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: de Roda Husman
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D009426:Netherlands; D062065:Wastewater / Q000382:microbiology*; D014871:Water Microbiology; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000890:Anti-Infective Agents; D062065:Wastewater; D001618:beta-Lactamases