Porcine E. coli: Virulence-Associated Genes, Resistance Genes and Adhesion and Probiotic Activity Tested by a New Screening Method

Abstract

We established an automated screening method to characterize adhesion of Escherichia coli to intestinal porcine epithelial cells (IPEC-J2) and their probiotic activity against infection by enteropathogenic E. coli (EPEC). 104 intestinal E. coli isolates from domestic pigs were tested by PCR for the occurrence of virulence-associated genes, genes coding for resistances to antimicrobial agents and metals, and for phylogenetic origin by PCR. Adhesion rates and probiotic activity were examined for correlation with the presence of these genes. Finally, data were compared with those from 93 E. coli isolates from wild boars.Isolates from domestic pigs carried a broad variety of all tested genes and showed great diversity in gene patterns. Adhesions varied with a maximum of 18.3 or 24.2 mean bacteria adherence per epithelial cell after 2 or 6 hours respectively. Most isolates from domestic pigs and wild boars showed low adherence, with no correlation between adhesion/probiotic activity and E. coli genes or gene clusters. The gene sfa/foc, encoding for a subunit of F1C fimbriae did show a positive correlative association with adherence and probiotic activity; however E. coli isolates from wild boars with the sfa/foc gene showed less adhesion and probiotic activity than E. coli with the sfa/foc gene isolated from domestic pigs after 6 hour incubation.In conclusion, screening porcine E. coli for virulence associated genes genes, adhesion to intestinal epithelial cells, and probiotic activity revealed a single important adhesion factor, several probiotic candidates, and showed important differences between E. coli of domestic pigs and wild boars.

Prevalence of Virulence Determinants and Antimicrobial Resistance among Commensal Escherichia coli Derived from Dairy and Beef Cattle

“…Genes bfpB , estII , eltA , faeG , fanC , fasA , fedA , f41 , papA , sfaS were not found in any of the isolates. The fimH gene was present in all tested isolates, other reports also indicated current prevalence of this gene both among pathogenic and commensal E. coli [ 18 , 19 ] therefore, in the further analysis the fimH gene was not considered as a virulence factor. Five and eight different virulence profiles were observed among E. coli isolates derived from dairy and beef cattle respectively ( Table 1 A,B).…”

Quantitative analysis of commensal Escherichia coli populations reveals host‐specific enterotypes at the intra‐species level

“…The gene sfa/foc , which encodes a subunit of F1C fimbriae, may enable adherence to intestinal porcine epithelial cells (Schierack et al. ). The E. coli Nissle 1917 strain, a robust colonizer of the human gastrointestinal tract, requires F1C fimbriae to make biofilms.…”

“…Indeed, we show that (1) B2 clones isolated from humans correspond mainly to classical extraintestinal pathogenic clones including subgroups I (STc131), II (STc73), and IX (STc 95) (Clermont et al 2014), whereas those isolated from animals correspond to a much wider range of subgroups (six of 13 strains were unassignable using our targeted subgroup characterization) (Table S1); and (2) "exclusive" dominant B2 strains in humans are characterized by two specific virulence factor, sfa/foc and pks. The gene sfa/foc, which encodes a subunit of F1C fimbriae, may enable adherence to intestinal porcine epithelial cells (Schierack et al 2013). The E. coli Nissle 1917 strain, a robust colonizer of the human gastrointestinal tract, requires F1C fimbriae to make biofilms.…”

Adhesion of Human and Animal Escherichia coli Strains in Association with Their Virulence-Associated Genes and Phylogenetic Origins

“…They are encoded by the sfa and the foc gene cluster but display distinct receptor specificities (12,13). It has been demonstrated that F1C fimbriae also support cell adhesion and subsequent colonization and biofilm formation in the intestine (14,15).…”