title: Assessment of Adhesins as an Indicator of Pathovar-Associated Virulence Factors in Bovine Escherichia coli.
abstract: The CS31A, F17, and F5 adhesins are usually targeted by serology-based methods to detect pathogenic Escherichia coli associated with calf enteritis. However, the virulence traits of the selected isolates are still poorly described. Here, from a set of 349 diarrheagenic E. coli isolates from cattle, we demonstrated a 70.8% concordance rate (Cohen's kappa, 0.599) between serology- and PCR-based approaches for the detection of adhesins under field conditions. A 79% to 82.4% correspondence between the two methods was found for fimbrial adhesins, whereas major discrepancies (33%) were observed for CS31A-type antigens. Various F17A variants were found, such as F17Ac (20K) (50%), F17Aa (FY) (18.9%), F17Ab (8.1%), and F17Ad (111K) (5.4%), including a high proportion (17.6%) of new F17A internal combinations (F17Aab, F17Aac, and F17Abc) or untypeable variants. In addition, the highest proportion of pathovar-associated virulence factor (VF) genes was observed among E. coli isolates that produced F5/F41 adhesins. A specific link between the heat-stable toxins related to the enterotoxigenic E. coli (ETEC) pathovar and adhesins was identified. STa was significantly linked to F5/F41 and EAST1 to CS31A adhesins (P < 0.001), respectively, whereas NTEC was associated with F17 adhesin (P = 0.001). Clustering between phylogroups according to the adhesin types was also observed. Also, few Shiga toxin-producing E. coli (STEC) or enteropathogenic E. coli (EPEC) pathovars were identified. Finally, no statistically significant difference was observed in the occurrence of extended-spectrum beta lactamase (ESBL) production according to the adhesins expressed by the isolates (P = 0.09). Altogether, this study gives new insights into the relationship between adhesins, VF, and antimicrobial resistance in calf enteritis and supports the need for further standardization of methodologies for such approaches.
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France charlotte.valat@anses.fr.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Valat
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Forest
authors.affiliation: Université Paris Est, Anses, Laboratoire de Sécurité des Aliments, Unité SBCL, Maisons-Alfort, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Auvray
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Métayer
authors.affiliation: Université Paris Est, Anses, Laboratoire de Sécurité des Aliments, Unité SBCL, Maisons-Alfort, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Méheut
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France.
authors.forename: Charlène
authors.initials: C
authors.lastname: Polizzi
authors.affiliation: Anses, Laboratoire de Lyon, Unité Epidémiologie, Lyon, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Gay
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France.
authors.forename: Marisa
authors.initials: M
authors.lastname: Haenni
authors.affiliation: Centre de Physiopathologie de Toulouse-Purpan, INSERM UMR1043-CNRS UMR5282-Universite Toulouse III, INRA USC1360, CHU Purpan, Toulouse, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Oswald
authors.affiliation: Anses, Laboratoire de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Madec
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis / Q000235:genetics*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004751:Enteritis / Q000382:microbiology / Q000662:veterinary*; D004926:Escherichia coli / Q000737:chemistry* / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D005838:Genotype; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D065288:Serogroup; D037521:Virulence Factors / Q000032:analysis / Q000235:genetics*
chemical_list: D018829:Adhesins, Bacterial; D037521:Virulence Factors