Prevalence and serotypes of Shiga toxin-producing Escherichia coli (STEC) in dairy cattle from Northern Portugal

PLoS One. 2020 Dec 31;15(12):e0244713. doi: 10.1371/journal.pone.0244713. eCollection 2020.

Abstract

The prevalence of Shiga toxin (Stx)-producing Escherichia coli (STEC) was determined by evaluating its presence in faecal samples from 155 heifers, and 254 dairy cows in 21 farms at North of Portugal sampled between December 2017 and June 2019. The prevalence of STEC in heifers (45%) was significantly higher than in lactating cows (16%) (p<0.05, Fisher exact test statistic value is <0.00001). A total of 133 STEC were isolated, 24 (13.8%) carried Shiga-toxin 1 (stx1) genes, 69 (39.7%) carried Shiga-toxin 2 (stx2) genes, and 40 (23%) carried both stx1 and stx2. Intimin (eae) virulence gene was detected in 29 (21.8%) of the isolates. STEC isolates belonged to 72 different O:H serotypes, comprising 40 O serogroups and 23 H types. The most frequent serotypes were O29:H12 (15%) and O113:H21 (5.2%), found in a large number of farms. Two isolates belonged to the highly virulent serotypes associated with human disease O157:H7 and O26:H11. Many other bovine STEC serotypes founded in this work belonged to serotypes previously described as pathogenic to humans. Thus, this study highlights the need for control strategies that can reduce STEC prevalence at the farm level and, thus, prevent food and environmental contamination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / genetics*
  • Animals
  • Cattle
  • Escherichia coli Infections / microbiology
  • Escherichia coli Infections / veterinary*
  • Escherichia coli Proteins / genetics*
  • Feces / microbiology*
  • Female
  • Portugal
  • Serogroup
  • Serotyping
  • Shiga-Toxigenic Escherichia coli / genetics
  • Shiga-Toxigenic Escherichia coli / isolation & purification*
  • Virulence

Substances

  • Adhesins, Bacterial
  • Escherichia coli Proteins
  • eaeA protein, E coli

Grants and funding

This study was financially supported by: i) project PhageSTEC (POCI-01-0145 -FEDER-029628) funded by FEDER through COMPETE2020 (Programa Operacional Competitividade e Internacionalização) and by National Funds thought FCT (Fundação para a Ciência e a Tecnologia); ii) strategic project UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by FCT under the scope of the European Regional Development Fund (Norte2020 - Programa Operacional Regional do Norte); iii) project PI16/01477 from Plan Estatal de I+D+I 2013-2016, Instituto de Salud Carlos III (ISCIII), Subdirección General de Evaluación y Fomento de la Investigación, Ministerio de Economía y Competitividad (Gobierno de España) and FEDER; and iv) grant ED431C2017/57 from the Consellería de Cultura, Educación e Ordenación Universitaria, (Xunta de Galicia) and FEDER; UIDB/AGR/04033/2020 by National Funds thought FCT. Author IGM acknowledges the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia for the individual grant ED481A-2015/149 and and author SCFS acknowledges the FPU programme for the individual grant FPU15/02644 from the Secretaría General de Universidades, Spanish Ministerio de Educación, Cultura y Deporte. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.