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

Abstract

SIUMMARYThe distribution of the Escherichia coli attaching and effacing (eae) gene in strains of verotoxin-producing E. coli (VTEC) isolated from cattle and humans was studied. The majority of strains isolated from humans with bloody diarrhoea or HUS and cattle with severe diarrhoea were eae positive (82 and 83 % respectively). In contrast, 59 % of VTEC isolated from asymptomatic cattle were eae negative and of the remaining 41 % that were eae positive, the majority were serotype 0157.H7. The nucleotide sequence of the 3' end of the eae gene of enteropathogenic E. coli (EPEC) of serotype 055.H7 was found to be almost identical to that of serotype 0157. H7. Specific primers are described which detect the eae sequences of VTEC serotypes 0157.H7, 0157.H-, and EPEC serotypes 055. H7 and 055. H-. The nucleotide sequence of the 3' end of the eae gene of serotype O111.H8 differed significantly from that of 0157.H7. Primers were developed to specifically identify the eae sequences of VTEC serotypes 0111 . Hand 0111 . H8. We conclude that whereas the majority of VTEC associated with disease in cattle and humans possess the eae gene, the gene itself may not be necessary to produce haemorrhagic colitis and HUS. Sequence heterogeneity in the 3' end of eae alleles of VTEC permits specific identification of subsets of these organisms.

Characterization of verocytotoxin-producingEscherichia coliO157 isolates from patients with haemolytic uraemic syndrome in Western Europe

“…The presence of the eae gene has been closely associated with 0157 VTEC that caused HUS and is assumed to be a virulence marker [33][34][35][36]. Our results strongly support this suggestion.…”

The prevalence and characterization of verotoxin-producing Escherichia coli isolated from cattle and pigs in an abattoir in Hong Kong

“…Detection of eaeA and EHEC-hlyA genes in VTEC isolates VTEC isolates confirmed by vero cell assay were studied for their eaeA and EHEC-hlyA genes by multiplex PCR. The primers were based on the central conserved region and the 5h region of the respective genes [14,15]. The PCR reaction mix was identical to that for t gene detection.…”

Distribution of serotypes and virulence-associated genes in pathogenicEscherichia coliisolated from ducks

“…A variety of virulence factors has been investigated to understand these extraintestinal diseases in avian species, including adhesins (F1-fimbriae, P-fimbriae, and F17-fimbriae, curli fibres, and afimbrial adhesins), haemolysins (haemolysin A/E and a temperature-sensitive haemagglutinin), iron-acquisition systems (aerobactin and yersiniabactin), antibactericidal factors (invasion of brain endothelium protein A, outer membrane protein A, protein for increased serum survival), and toxins (Shiga toxin 1 and 2, heat stable toxin, and flagella toxin) (Hacker et al, 1983;Louie et al, 1994;Kaper et al, 1997;Ludwig et al, 1999;Nagy et al, 2002;Parreira & Gyles, 2002;Ewers et al, 2004;Schubert et al, 2004;Germon et al, 2005;Beloin et al, 2006;Capitani et al, 2006;Belogurov et al, 2009). According to recent studies, many virulence genes associated with APEC are located on large plasmids, the importance of those large plasmids has been demonstrated by the plasmid-encoded genes shared among APEC strains (Dozois et al, 2003;Johnson et al, 2008;Tivendale et al, 2009).…”