Background: Escherichia coli is a bacterial species widely distributed among mammals and avian species, and also a member of the normal intestinal microbiota. However, some E. coli strains of different pathotypes can cause disease in both humans and animals. Atypical enteropathogenic E. coli (aEPEC) can infect both animals and humans or influence the severity of other ongoing infections. Results: In the present study, a total of 332 samples were collected from ducks, geese, turkeys, chickens, and pigeons from the Hungarian Veterinary Diagnostic Directorate, two slaughterhouses, two pigeon keepers and one backyard chicken farm. E. coli was isolated and verified from 319 samples. The isolates were screened by PCR for diarrheagenic E. coli pathotypes. Altogether seven atypical enteropathogenic E. coli (aEPEC) strains were identified: two from four-week-old dead turkeys, two from force-fed geese, and three from pigeons. No further pathotypes were identified in the collection. The atypical EPEC strains were classified phylogenetically to B1, B2, and F, and four out of the seven aEPEC isolates proved to be multidrug resistant. Serotypes of aEPEC strains were uniform collected from same farms and showed diversity between their origins with O76, O145, O109 serogroups. Conclusions: This is the first report in the literature about aEPEC in goose (Anser anser domestica). Furthermore, this is the first isolation of aEPEC from turkeys and pigeons in Hungary. The uneven distribution of aEPEC in different age groups of poultry suggests that aEPEC disappears with growing up, but stress (e.g.: force-feeding) and concurrent diseases might promote its reappearance in the intestine.

Extraintestinal pathogenic Escherichia coli (ExPEC) strains are capable of causing various systemic infections in both humans and animals. In this study, we isolated and characterized 30 E. coli strains from the parenchymatic organs and brains of young (<3 months of age) camel calves which died in septicemia. Six of the strains showed hypermucoviscous phenotype. Based on minimum inhibitory concentration (MIC) values, seven of the strains were potentially multidrug resistant, with two additional showing colistin resistance. Four strains showed mixed pathotypes, as they carried characteristic virulence genes for intestinal pathotypes of E. coli: three strains carried cnf1, encoding cytotoxic necrotizing factor type 1, the key virulence gene of necrotoxigenic E. coli (NTEC), and one carried eae encoding intimin, the key virulence gene of enteropathogenic E. coli (EPEC). An investigation of the integration sites of pathogenicity islands (PAIs) and the presence of prophage-related sequences showed that the strains carry diverse arrays of mobile genetic elements, which may contribute to their antimicrobial resistance and virulence patterns. Our work is the first to describe ExPEC strains from camels, and points to their veterinary pathogenic as well as zoonotic potential in this important domestic animal.

Cytolethal distending toxin (CDT), a cyclomodulin and genotoxin produced by many Gram-negative bacteria including pathogenic Escherichia coli, disrupts the eukaryotic host cell cycle to facilitate bacterial colonization. In a survey of dairy cows in Hungary, 7 % of of sampled animal and farm environment isolates carried CDT-producing E. coli (CTEC). Whole genome sequencing (WGS) performed on six recent isolates and three historical CTEC strains revealed association with diverse pathotypes, including enteropathogenic- (EPEC) and necrotoxigenic- (NTEC) types, as well as several unclassified atypical strains. Four of the six strains isolated in this study carried plasmid encoding cdt-III+ NTEC, while a prophage based cdt-V allele was present in the remaining two strains which were of unknown pathotype. These isolates exhibited significant variability in their supplementary virulence genes (SVGs) content as well as in multiple prophage regions linked to virulence or fitness factors. They were phylogenetically distinct and comprised of only distantly related sequence types (STs) that include two novel STs. Several isolates also carried other genotoxic cyclomodulins such as the cytotoxic necrotizing factor (cnf), the cycle inhibiting factor (cif), and colibactin (polyketide synthase, pks) which is located on a genomic island, indicating multiple mechanisms for dysplastic damage of the eukaryotic host cells exist and highlight the role of horizontal gene transfer in the zoonotic and pathogenic potential of CTEC.