title: High prevalence of antimicrobial-resistant Escherichia coli from animals at slaughter: a food safety risk.
abstract: BACKGROUND
  There has been concern about the increase of antimicrobial resistant bacteria and protection of animal and public health, along with food safety. In the present study, we evaluate the incidence of antimicrobial resistance among 192 strains of Escherichia coli isolated from faecal samples of healthy food-producing animals at slaughter in Portugal.
  
  
  RESULTS
  Ninety-seven % of the pig isolates, 74% from sheep and 55% from cattle were resistant to one or more antimicrobial agents, with the resistances to ampicillin, streptomycin, tetracycline and trimethoprim-sulfamethoxazole the most common phenotype detected. Genes encoding resistance to antimicrobial agents were detected in most of the resistant isolates. Ninety-three % of the resistant isolates were included in the A or B1 phylogenetic groups, and the virulence gene fimA (alone or in association with papC or aer genes) was detected in 137 of the resistant isolates. Five isolates from pigs belonging to phylogroup B2 and D were resistant to five different antimicrobial agents.
  
  
  CONCLUSIONS
  Our data shows a high percentage of antibiotic resistance in E. coli isolates from food animals, and raises important questions in the potential impact of antibiotic use in animals and the possible transmission of resistant bacteria to humans through the food chain.
authors: Centre of Studies of Animal and Veterinary Sciences, Vila Real, Portugal.
authors: Sónia
authors: S
authors: Ramos
authors: Nuno
authors: N
authors: Silva
authors: Manuela
authors: M
authors: Caniça
authors: José Luis
authors: JL
authors: Capelo-Martinez
authors: Francisco
authors: F
authors: Brito
authors: Gilberto
authors: G
authors: Igrejas
authors: Patrícia
authors: P
authors: Poeta
mesh_terms: D000003:Abattoirs; D000818:Animals; D002417:Cattle; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D059022:Food Safety; D005798:Genes, Bacterial; D010802:Phylogeny; D011174:Portugal; D012756:Sheep; D013552:Swine; D037521:Virulence Factors / Q000235:genetics
chemical_list: D037521:Virulence Factors