Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease

Abstract

Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence.

Antimicrobial Resistance Genes and Diversity of Clones among ESBL- and Acquired AmpC-Producing Escherichia coli Isolated from Fecal Samples of Healthy and Sick Cats in Portugal

“…Regarding the ST40 clone, a relation between diarrheal disease and the presence of this lineage (containing specific virulence genes) was recently found among clinical isolates from patients in the United Kingdom [55]. Furthermore, the ST429 lineage was found in our study in CMY-2-and CTX-M-15-producing isolates of healthy cats.…”

Antimicrobial Resistance in Escherichia coli Strains Isolated from Humans and Pet Animals

“…The results point to several extremely interesting facts. This bacterium undoubtedly has considerable influence on human and animal lives [ 47 , 48 ], for the simple reason that it lives inside the gut and can very easily spread from fecal matter to the mouth [ 49 , 50 ]. Being the commensal bacteria of human and animal gut, it happens to be in close contact with numerous other bacteria [ 51 ].…”

Antimicrobial resistance profiles of diarrhoeagenic Escherichia coli isolated from travellers returning to the UK, 2015–2017

“…Previous studies have shown evidence that EAEC and EPEC pathotypes are isolated from both symptomatic and asymptomatic individuals [15, 16]. The pathogenic potential of DEC is influenced by a number of different factors, including host susceptibility, the ingested bacterial load and the presence of virulence genes and the different subtypes and combinations of these virulence genes [17–19]. Where EPEC and/or EAEC are detected in patients reporting to primary health care with symptoms of gastrointestinal disease, where no other gastrointestinal pathogens are detected, these DEC pathotypes may be considered as the aetiological agent, particularly if the patient reports recent travel outside the UK, or in the case infection with EPEC the patient is aged 2 years or under [17, 20].…”