Identification of enteropathogenic Escherichia coli isolated in Britain as enteroaggregative or as members of a subclass of attaching-and-effacing E. coli not hybridising with the EPEC adherence-factor probe

Abstract

I d e n t if i ca t i o n of en t e ro p a t h oge n i c Escherichia co/iSummary. Strains of Escherichia coli from sporadic cases of diarrhoea and belonging to serotypes 044 : H 18,055 : H7,O 1 1 lab : H2 1,011 1 ab : H25 or 0 126 : H27 were examined for virulence properties. With the exception of 0 1 1 lab: H25 these are considered to be classical enteropathogenic E. coli (EPEC) serotypes. The strains had been isolated in Britain from the faeces of children < 3 years old. Of the serotypes examined, 7 of 13 044 : H 18 strains, all of 10 0 1 1 lab : H21 strains and 13 of 21 0126 : H27 strains belonged to the enteroaggregative class of E. coli (EAggEC) that attached to HEp-2 cells in the characteristic aggregative pattern and hybridised with the EAggEC probe. They also caused mannose-resistant haemagglutination of rat erythrocytes, a property which may be a useful marker for their identification. Strains of 044 : H18 with similar properties were also isolated from three small outbreaks in Britain, one of which involved elderly patients. EAggEC have not been considered previously as aetiological agents of diarrhoea in developed countries and have rarely been reported as belonging to EPEC serotypes. All 15 055 : H7 strains and seven of eight 0 1 1 lab: H25 strains were also considered to be potentially diarrhoeagenic as they gave localised attachment (LA) to HEp-2 cells that resulted in a positive fluorescence actinstaining test. This test is considered to correlate with the attaching-and-effacing virulence mechanisms of EPEC in vivo. None of the strains in this study hybridised with the EPEC adherence-factor (EAF) probe. Neither the aggregative EPEC nor the LA-positive EAFnegative EPEC described here would be identified in epidemiological surveys when the EAF probe is used in the absence of cell tests.

Serotyping and categorisation of Escherichia coli strains isolated between 1958 and 1992 from diarrhoeal diseases in Asia

“…It is interesting that enteroaggregative strains of E. coli (EAggEC) have been implicated epidemiologically as one of the aetiological agents of diarrhoea [12-141. Even in EPEC serogroups, it has been suggested that EAggEC strains are probably more important than those which are EAF-positive [15]. On the other hand, it has also been proposed that some E. coli strains showing 'diffuse adherence' (DAEC) also K. TAMURA E T A L .…”

Genetic relationships and virulence factors among classical enteropathogenic Escherichia coli serogroup 0126 strains

“…The finding that 0126:H10, categorised as EAggEC, is noteworthy in the light of the recent report by Scotland et al that the EPEC strains of serotype 0126: H27, obtained from patients with diarrhoea in the UK, were in fact EAggEC. 39 Further study of E. coli as a diarrhoea1 agent depends on increased understanding of the pathogenesis of the disease. This study presents the results of comprehensive screening of virulence factors in diarrhoeagenic E. coli.…”

Sequence heterogeneity of theeaegene and detection of verotoxin-producingEscherichia coliusing serotype-specific primers

“…H21 and a single isolate of 055. H4 have previously been shown to exhibit enteroaggregative E. coli (EAggEC) adherence characteristics and to hybridize with the EAggEC probe [48,49].…”