title: Molecular characterization and antimicrobial resistance of STEC strains isolated from healthy cattle in 2011 and 2013 in Spain.
abstract: Prevention of Shiga toxin-producing Escherichia coli (STEC) foodborne outbreaks is hampered by its complex epidemiology. We assessed the distribution of virulence genes (VGs), main serogroups/serotypes for public health [haemolytic uraemic syndrome (HUS)-related], antimicrobial resistance (AMR) profiles and pulsed-field gel electrophoresis (PFGE) patterns in a collection of STEC isolates obtained from cattle hide (n = 149) and faecal (n = 406) samples collected during a national survey conducted in Spain in 2011 and 2013. Isolates were cultured using McConkey and CT-SMAC agar after enrichment, and confirmed as STEC by PCR. STEC prevalence in hides (15·4%) was higher than in faeces (10·7%) and O157:H7 was more frequent in the former (2·7% vs. 0·99%). Non-O157 HUS-related serogroups were present albeit at low frequencies. The non-O157 isolates were more heterogeneous than O157:H7 in their VG patterns, with 25/64 presenting VGs from both STEC and enterotoxigenic pathotypes (hybrid isolates). Of the STEC isolates, 62·5% were resistant at least to one antimicrobial, and no differences in AMR between O157:H7 and non-O157 were detected. All isolates had different profiles by PFGE and did not form a cluster. Overall, our results demonstrated that STEC in the cattle reservoir is still a matter of concern for human health due to the presence of HUS-related serogroups, the occurrence of certain VGs, AMR and the additional risks that hybrid isolates may pose, and thus warrants further investigation.
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense,Madrid,Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cabal
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense,Madrid,Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Porrero
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense,Madrid,Spain.
authors.forename: M L
authors.initials: ML
authors.lastname: DE LA Cruz
authors.affiliation: Subdirección General de Sanidad e Higiene Animal y Trazabilidad,Ministerio de Agricultura,Alimentación y Medio Ambiente,Madrid,Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Saez
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense,Madrid,Spain.
authors.forename: C
authors.initials: C
authors.lastname: Barcena
authors.affiliation: Subdirección General de Sanidad e Higiene Animal y Trazabilidad,Ministerio de Agricultura,Alimentación y Medio Ambiente,Madrid,Spain.
authors.forename: G
authors.initials: G
authors.lastname: Lopez
authors.affiliation: SaBio IREC (CSIC-UCLM-JCCM),Ciudad Real,Spain.
authors.forename: C
authors.initials: C
authors.lastname: Gortazar
authors.affiliation: VISAVET Health Surveillance Centre, Universidad Complutense,Madrid,Spain.
authors.forename: L
authors.initials: L
authors.lastname: Dominguez
authors.affiliation: Department of Veterinary Population Medicine,College of Veterinary Medicine, University of Minnesota,St Paul,MN,USA.
authors.forename: J
authors.initials: J
authors.lastname: Alvarez
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D010802:Phylogeny; D065288:Serogroup; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D013030:Spain / Q000453:epidemiology; D037521:Virulence Factors
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors
keywords: Molecular epidemiology; Shiga-like toxin-producing E. coli
              ; public health; pulsed-field gel electrophoresis (PFGE); zoonotic foodborne diseases