title: Human influence and biotic homogenization drive the distribution of Escherichia coli virulence genes in natural habitats.
abstract: Cattle are the main reservoirs for Shiga-toxin-producing Escherichia coli (STEC), the only known zoonotic intestinal E. coli pathotype. However, there are other intestinal pathotypes that can cause disease in humans, whose presence has been seldom investigated. Thus, our aim was to identify the effects of anthropic pressure and of wild and domestic ungulate abundance on the distribution and diversity of the main human E. coli pathotypes and nine of their representative virulence genes (VGs). We used a quantitative real-time PCR (qPCR) for the direct detection and quantification of the genus-specific gene uidA, nine E. coli VGs (stx1, sxt2, eae, ehxA, aggR, est, elt, bfpA, invA), as well as four genes related to O157:H7 (rfbO157, fliCH7) and O104:H4 (wzxO104, fliCH4) serotypes in animals (feces from deer, cattle, and wild boar) and water samples collected in three areas of Doñana National Park (DNP), Spain. Eight of the nine VGs were detected, being invA, eae, and stx2 followed by stx1, aggR, and ehxA the most abundant ones. In quantitative terms (gene copies per mg of sample), stx1 and stx2 gave the highest values. Significant differences were seen regarding VGs in the three animal species in the three sampled areas. The serotype-related genes were found in all but one sample types. In general, VGs were more diverse and abundant in the northern part of the Park, where the surface waters are more contaminated by human waste and farms. In the current study, we demonstrated that human influence is more relevant than host species in shaping the E. coli VGs spatial pattern and diversity in DNP. In addition, wildlife could be potential reservoirs for other pathotypes different from STEC, however further isolation steps would be needed to completely characterize those E. coli.
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense, Madrid, Spain.|SaBio IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Adriana
authors.identifier: 0000-0001-9346-1612
authors.initials: A
authors.lastname: Cabal
authors.affiliation: SaBio IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Vicente
authors.affiliation: Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Alvarez
authors.affiliation: SaBio IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Jose Angel
authors.initials: JA
authors.lastname: Barasona
authors.affiliation: SaBio IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Mariana
authors.initials: M
authors.lastname: Boadella
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense, Madrid, Spain.
authors.forename: Lucas
authors.initials: L
authors.lastname: Dominguez
authors.affiliation: SaBio IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Christian
authors.initials: C
authors.lastname: Gortazar
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D000835:Animals, Wild; D002417:Cattle; D003670:Deer; D017753:Ecosystem; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D019143:Evolution, Molecular; D005243:Feces / Q000382:microbiology; D005838:Genotype; D060888:Real-Time Polymerase Chain Reaction; D013030:Spain; D034421:Sus scrofa; D037521:Virulence Factors / Q000235:genetics*; D014871:Water Microbiology
chemical_list: D037521:Virulence Factors
keywords: 
  Escherichia coli
  ; natural habitats; pathotypes; virulence genes; wildlife