Summary auto-generated
This study examined nine archetypal strains of enteropathogenic Escherichia coli (EPEC) isolated from infants with diarrhea between 1947 and 1960 to determine if they met modern virulence criteria. Each strain belonged to a different serotype and represented historically significant early isolates linked to infantile diarrhea. Researchers tested the strains for phenotypic and genetic virulence properties using multiple methods: adhesion assays to cultured cells, fluorescent actin staining, in vivo attachment-effacement lesions in rabbit intestine, cytotoxin production, and DNA probe hybridization. Results showed five strains possessed class I EPEC properties (eae and EAF genes, localised adherence, attachment-effacement lesions), predominantly from epidemic cases. Two strains from sporadic cases were classified as class II EPEC (eae-positive, EAF-negative). One strain was identified as enteroaggregative E. coli, and one carried no known virulence factors. No strains produced Shiga-like toxins or possessed enterotoxigenic or enteroinvasive properties. The findings confirm that most early EPEC isolates designated "enteropathogenic" were indeed true EPEC according to current definitions, validating both the original serotyping approach and the historical significance of these strains in identifying E. coli as a diarrheal pathogen.
Key findings
- Five of nine archetypal EPEC strains (56%) met current class I EPEC criteria, characterized by possession of eae and EAF genes, localised adherence, and ability to produce attachment-effacement lesions in rabbit intestine
- Class I EPEC strains were predominantly isolated from diarrheal outbreaks, while class II EPEC and other pathotypes were found in sporadic cases
- No strains possessed virulence properties of enterotoxigenic, enteroinvasive, or enterohaemorrhagic E. coli, demonstrating EPEC represents a distinct pathogenic category
- One strain was identified as enteroaggregative E. coli and one possessed no known virulence determinants, suggesting not all early "enteropathogenic" designations were accurate
- Excellent agreement between phenotypic assays (adhesion patterns, FAS test, animal models) and genotypic methods (DNA probe hybridization) validated modern EPEC identification criteria
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
Nine strains of Escherichia coli isolated from infants with diarrhoea between 1947 and 1960 and designated "enteropathogenic" were examined for phenotypic and genetic characters associated with virulence. Each strain belonged to a different serotype. All the isolates were historically significant in that they were amongst the first strains of E. coli reported to be causally associated with infantile diarrhoea. Five strains possessed the virulence properties of class I enteropathogenic E. coli (EPEC). All these strains were isolated originally from symptomatic children during outbreaks of diarrhoea. Two isolates from sporadic cases of diarrhoea fulfilled the criteria for classification as class II EPEC. One strain was identified as enteroaggregative E. coli and the other carried no known virulence-associated properties. These findings indicate that most early isolates of E. coli which were designated "enteropathogenic" were indeed EPEC, as currently defined.