Genomic characterization of enteropathogenic <i>Escherichia coli</i> (EPEC) of avian origin and rabbit ileal loop response; a pet macaw (<i>Ara chloropterus</i>) as a possible zoonotic reservoir

Enteropathogenic <i>Escherichia coli</i> (EPEC) constitutes one of the main causes of mortality in children in low- to medium-income countries. Diverse animal species have been linked as reservoirs, including birds. The aim of this study was to describe the genomic and phylogenetic features of an EPEC recovered from a pet macaw and further characterizing the macro and microscopic lesion in a rabbit ileal loop experimental model. The isolate was whole-genome sequenced (WGS) obtaining its genotypic and phenotypic <i>in silico</i> characteristics and inoculated in a rabbit experimental model with subsequently evaluating the strain’s pathogenicity by scanning electron microscopy (SEM) and histopathology. The isolate was characterized as O109:H21-B1-ST40 typical EPEC, harboring several virulence factors of diarrheagenic <i>E. coli</i>. The macaw EPEC genome was located in a monophyletic clade of human and animal ST40 EPEC sequences. <i>In vivo</i> inoculation demonstrated severe hemorrhage with SEM and histopathological analysis confirming these lesions to be associated with intra-epithelial lymphocytes. Therefore, the isolate not only shared several genotypic and phylogenetic similarities with EPEC that affects humans and animals, but was able to induce severe tissue injury in a mammal model. These findings highlight the underrated role of pet birds as zoonotic reservoirs and the diversity in virulence factors being unraveled by new WGS studies.