Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics

Abstract

This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin-producing E. coli (VTEC), isolated in a case-control study of Danish children aged <5 years. Among 424 children with diarrhoea and 866 healthy controls, EPEC and VTEC were more prevalent in cases (2.4% and 2.6%, respectively) than in controls (0.7% and 0.7%, respectively). There was a high frequency of A/EEC isolates (n = 121), but these were equally prevalent in cases (11.3%) and controls (12.5%), and comprised a heterogeneous distribution of O:H serotypes. The intimin (eae) subtypes in A/EEC isolates showed an even distribution; the eae-gamma subtype predominated in classical EPEC cases. The virulence genes encoding the bundle-forming pilus (bfpA) and enteroaggregative heat-stable enterotoxin (astA) were rare among all isolates, and seemed to be of limited pathogenic importance in this population. Virulence characterisation of A/EEC isolates did not reveal any significant differences between cases and controls. Colonisation of children with A/EEC was associated with contact with sheep or goats (OR 2.2). The role of A/EEC, not being VTEC or belonging to the classical EPEC serotypes, requires further clarification, but serotyping is useful in discriminating between EPEC and A/EEC strains.

Molecular and phenotypic typing of enteropathogenic Escherichia coli isolated in childhood acute diarrhea in Abuja, Nigeria

“…Among the types, intimin β was the most common subtype identified in both typical and atypical EPEC strains and was distributed over six serotypes. Contrary to our findings, earlier studies had reported detection of intimin θ and γ allele from children with diarrhea in Uruguay and Denmark, respectively [8,47]. Remarkably, the predominance of intimin β in this study is in consonance with several reports that describe intimin β as the most ubiquitous found among human and animal A/E pathogens [48].…”

“…It has recently emerged and been genotyped as the most predominant intimin type among atypical EPEC strains from children with and without diarrhea [47]. Conversely, our report of intimin ε expression by typical EPEC strains reflects the dynamics in the expression of intimin alleles and variants among E. coli pathotypes.…”

DiarrheagenicEscherichia coliandShigellaStrains Isolated from Children in a Hospital Case-Control Study in Hanoi, Vietnam

“…Identification of somatic (O) and flagellar (H) antigens was done by tube and microtiterplate agglutination with specific antisera O1-O181 supplemented with presumptive new O groups OX182-OX186 and H1-H56 as previously described (45). E. coli strains (vtx negative) reacting with the eae probe belonging to one of the classical EPEC serotypes (O26:NM, O26:H11, O26:H34, O55:NM, O55:H6, O55: H7, O86:NM, O86:H34, O111:NM, O111:H2, O111:H25, O114:NM, O114:H2, O119:NM, O119:H2, O119:H6, O125:H-, O125:H6, O125:H21, O126:NM, O126: H2, O126:H21, O126:H27, O127:NM, O127:H6, O126:H21, O128:NM, O128:H2, O128:H7, O128:H12, O142:NM, O142:H6, O158:NM, and O158:H23) were classified as EPEC (27). Serotypes O39:NM, O88:H25, O111:H8, O111:H9, O126:H12, O127:H4, O145:H45, O157:H8, and O157:H45 were considered new EPEC strains (27).…”

“…E. coli strains (vtx negative) reacting with the eae probe belonging to one of the classical EPEC serotypes (O26:NM, O26:H11, O26:H34, O55:NM, O55:H6, O55: H7, O86:NM, O86:H34, O111:NM, O111:H2, O111:H25, O114:NM, O114:H2, O119:NM, O119:H2, O119:H6, O125:H-, O125:H6, O125:H21, O126:NM, O126: H2, O126:H21, O126:H27, O127:NM, O127:H6, O126:H21, O128:NM, O128:H2, O128:H7, O128:H12, O142:NM, O142:H6, O158:NM, and O158:H23) were classified as EPEC (27). Serotypes O39:NM, O88:H25, O111:H8, O111:H9, O126:H12, O127:H4, O145:H45, O157:H8, and O157:H45 were considered new EPEC strains (27). Strains not belonging to these serotypes were classified as A/EEC.…”

Relationship between Virulence Gene Profiles of Atypical Enteropathogenic Escherichia coli and Shiga Toxin- Producing E. coli Isolates from Cattle and Sheep in New Zealand

“…In addition to A/E lesion formation, many human EPEC strains possess the EPEC adherence factor (EAF) virulence plasmid containing an operon associated with the expression of bundle-forming pili (bfp) (30). Recent studies have suggested that EAF plasmid-negative EPEC may be associated with human diarrheal disease (1,2,16,17,23,26,31) and have also been isolated from ruminants (3,9,10,14,19,20,24). Consequently, these EAF plasmid-negative EPEC strains lacking the bfp locus have been described as atypical EPEC (aEPEC) strains to distinguish them from typical EAF plasmid-positive EPEC strains such as the progenitor strain O127:H6 E2348/69 (30).…”