Surveillance of enteropathogenic Escherichia coli in England, 2011-2024

Introduction. Enteropathogenic Escherichia coli (EPEC) is a diarrhoeagenic pathotype of E. coli, historically associated with gastrointestinal (GI) disease in infants and young children.Hypothesis/Gap statement. Although EPEC was the subject of extensive microbiological and epidemiological investigations throughout the twentieth century, in recent years, surveillance of diarrhoeagenic E. coli (DEC) has focused on Shiga toxin-producing E. coli. Consequently, the true clinical and community burden of EPEC is unknown.Aim. The aim of the study was to review the microbiological typing data and demographic data linked to EPEC isolates and cases diagnosed from 2011 to 2024 in England and to assess the risk to public health.Methodology. Faecal samples that tested positive by PCR for DEC at local microbiology diagnostic laboratories were referred to the UK Health Security Agency (UKHSA) for confirmation and culture. Isolates identified as EPEC were sequenced on the Illumina HiSeq and NextSeq platforms. Sequence type, serotype and antimicrobial resistance (AMR) profile were derived from the genome sequence. Age, sex and travel histories were linked to the typing data.Results. A total of 3,091 EPEC isolates from cases resident in England were notified to the UKHSA between January 2011 and October 2024, with 96% classified as atypical EPEC (aEPEC). The number of referred isolates increased more than eightfold, from 78 in 2011 to 654 in 2024, likely due to the widespread implementation of PCR for the detection of GI pathogens at the local hospital level. There was a slightly higher proportion of females (51.7%), and the highest proportion of cases occurred in the 0-4 age group (30.1%). Reported symptoms included diarrhoea (86.57%) and/or bloody diarrhoea (24.25%) and abdominal pain (9.05%), and 33 cases were diagnosed clinically with haemolytic uraemic syndrome. The population structure was diverse with 447 different serotypes identified, and 24.5% of isolates were resistant to three or more antibiotic classes.Conclusion. A high proportion of cases were infants or young children. Strains causing travellers' diarrhoea exhibited multidrug resistance and extensive drug resistance. Further research on potential animal reservoirs, likely food vehicles, exposure risks and pathogenic potential of EPEC, is warranted. To facilitate future investigations, we recommend that EPEC should be part of the diagnostic algorithm in the UK and that surveillance strategies should include analysis of travel data and monitoring AMR to inform the global perspective.