Serogroup O80 was detected in 40% of 104 enteropathogenic Escherichia coli isolates from calves with diarrhea from 42 farms in Belgium during 2008‒2015. These isolates harbored the eae-ξ and fliCH2 genes, similar to the O80 attaching-effacing Shigatoxigenic E. coli isolates found in humans in France. This strain might be emerging.

ObjectiveSince 1987 all fecal samples referred to the clinical microbiology laboratory of the UZ Brussel were screened for the presence of Shiga toxin-producing E. coli (STEC). In this study all STEC strains isolated over a period of 27 years (1987–2014) were reexamined to achieve deeper insight in the STEC infections in our patient population.MethodsA total of 606 STEC strains from 604 patients were subjected to molecular methods for shiga toxin (stx) subtyping, detection of additional virulence genes, typing of the O-serogroups, and phylogenetic relatedness assessment of STEC O157:H7/H-.ResultsSince the introduction of PCR in 1991 the annual positivity rates varied between 1.1% and 2.7%. The isolation rate of STEC O157:H7/H- remained stable over the years while the isolation rate of non-O157 serotypes increased, mainly since 2011. The majority of the patients were children. Uncomplicated- and bloody diarrhea were the most prevalent gastrointestinal manifestations (respectively 51.9% and 13.6%), 4.3% of the strains were related to the hemolytic uremic syndrome (HUS), and 30.2% of the patients showed none of these symptoms. The strains were very diverse; they belonged to 72 different O-serovars and all stx subtypes except stx1d and stx2g were identified. Out of the 23 stx2f-positives one was associated with HUS and one belonged to the E. albertii species. As seen in other studies, the frequency of strains of the O157:H7/H- serotype and strains carrying stx2a, eaeA and ehxA was higher in patients with HUS.ConclusionsThe characteristics and trends of STEC infection seen in our patient population are similar to those noted in other countries. STEC infections in our hospital are mainly sporadic, and a substantial portion of the patients were asymptomatic carriers. Human STEC Stx2f infection was less rare than previously assumed and we report the first Belgian STEC stx2f HUS case and stx2f positive E. albertii infection.

Aim: The purpose of this work was to identify and genetically characterize enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) O80:H2 from diarrhoeic and septicaemic calves in Belgium and to comparing them with human EHEC after whole genome sequencing. Methods and Results: Ten EHEC and 21 EPEC O80 identified by PCR between 2009 and 2018 from faeces, intestinal content and a kidney of diarrhoeic or septicaemic calves were genome sequenced and compared to 19 human EHEC identified between 2008 and 2019. They all belonged to the O80: H2 serotype and ST301, harboured the eaeξ gene, and 23 of the 29 EHEC contained the stx2d gene. Phylogenetically, they were distributed in two major sub-lineages: one comprised a majority of bovine EPEC whereas the second one comprised a majority of stx2d bovine and human EHEC. Conclusions: Not only EPEC but also EHEC O80:H2 are present in diarrhoeic and septicaemic calves in Belgium and are genetically related to human EHEC. Significance and Impact of the Study: These findings support the need to assess cattle as potential source of contamination of humans by EHEC O80:H2 and to understand the evolution of bovine and human EHEC and EPEC O80: H2.