Virulence genotype and phenotype of multiple Antimicrobial Resistant Escherichia coli isolates from Broilers assessed in a "One-Health" Perspective.

Extraintestinal pathogenic  Escherichia coli  (ExPEC) include several serotypes which have been associated with colibacillosis in poultry,while urinary tract infections (UTI) and newborn meningitis in humans. In this study, 57 antimicrobial resistant  E. coli  from apparently healthy broiler chickens were characterized for their health and safety risks. These isolates belonged to 12 serotypes and isolates of the same serotype were determined to be clonal based on Single Nucleotide Variant (SNV) analysis. Most of the isolates harbored plasmids, with  Inc  C and  Inc  FIA being frequently detected. The majority of the resistant isolates harboured plasmid-mediated resistance genes including  aph (3'')-Ib  ,  aph(6)-Id  ,  bla  CMY-2  ,  floR  ,  sul (1  and  2)  and  tet (A  and  B)  in agreement with their resistant phenotypes. The Class 1 integron was detected in all serotypes except O124:H25 and O7:H6. Of the 57 broilers  E. coli  , 27 were APEC among which 18 were also defined as uropathogenic  E. coli  (UPEC) and the remainder as other ExPEC. Two isolates of serotype O161:H4 (ST117) were genetically related to the control APEC and a clinical isolate associated with  UTI  . A strain of serotype O159:H45 (ST101) was also found to be closely related to an UTI case isolate. The detected virulence factors included adhesins, invasions, siderophores, type III secretion systems and toxins in combination with other virulence genes. A broiler isolate of serotype O7:H18 (ST 38) carried the  ibe  A gene encoding a protein involved in invasion of brain endothelium on a 102 kbp genetic island. This isolate demonstrated a moderate level of  Caco-2  cells invasion and induced mortality (42.5 %) in a day-old chick infection model.