Attaching and effacing Escherichia coli O103:K+:H- in red-legged partridges

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

Enteropathogenic Escherichia coli (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 in silico 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 E. coli. The macaw EPEC genome was located in a monophyletic clade of human and animal ST40 EPEC sequences. In vivo 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.

Occurrence of avian pathogenic Escherichia coli and antimicrobial-resistant E. coli in red-legged partridges (Alectoris rufa): sanitary concerns of farming

Red-legged partridges (Alectoris rufa) are a significant part of the culture, diet and income for many people in central and southern Spain. Due to declining populations in the wild, intensive farming is common and 4 million juvenile partridges are released each autumn. Intensive management and high densities result in high prevalence of enteric disease and the use of antimicrobials as preventive measures on partridge farms and prior to restocking in the wild. We determined the occurrence of avian pathogenic Escherichia coli (APEC), and screened phenotypic resistance of E. coli against enrofloxacin, gentamicin and cefotaxim in farmed, restocked and wild partridges. Prevalence of APEC in farmed and restocked red-legged partridges was significantly higher than in natural populations. Phenotypic resistance against both gentamicin and enrofloxacin was significantly more frequent in farmed (75%) and restocked (43%) partridges than in wild partridges, while most E. coli isolated from natural populations were susceptible to all three antimicrobials tested (65%). This indicates that farmed and restocked partridges carry APEC that could be a reason for disease outbreaks on farms, and that E. coli carried by farmed and restocked partridges can acquire resistance to frequently used antimicrobials, thus being a concern for the environment, wild birds and consumers. Management in farms and restocking procedures may create a hazard not only for spreading APEC, but also as a potential source of resistant E. coli in the environment.

A colibacillosis outbreak in farmed red-legged partridges (Alectoris rufa)

Colibacillosis in different forms is responsible for significant economic losses in the poultry industry worldwide. Escherichia coli strains frequently implicated in poultry disease are designated as avian pathogenic E. coli (APEC). Natural infections and disease due to APEC have been described in wild birds, but not as yet in red-legged partridges. During an outbreak in an experimental partridge farm, 23 of 43 1-day-old chicks belonging to the same batch died. Putative APEC strains were detected and isolated both in cloacal swabs and in tissues originating from the same individuals and from different birds showing similar clinical signs. This is the first study that identifies APEC strains linked to a colibacillosis outbreak in farmed red-legged partridges, and also confirms the importance of farmed partridges as fecal carriers and potential spreaders of APEC.

A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots

Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear's macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear's macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations.