Virulence determinants in nontoxinogenic Escherichia coli O157 strains that cause infantile diarrhea.
Ten sorbitol-fermenting Escherichia coli O157 strains that cause infantile diarrhea and are positive in the fluorescence actin staining test were determined to be negative for Shiga-like toxin (SLT) genes. We amplified their complete eae genes, contrasting them with those of SLT-producing E. coli O157 by restriction fragment length polymorphism analysis and nucleotide sequence analysis of a 400-bp stretch of the 3' end of eae. The data substantiated the presence of two eae genotypes within serogroup O157, one resembling eae of enteropathogenic E. coli (EPEC) strain E2348/69, found in nontoxinogenic E. coli O157 strains, and the other resembling eae of EHEC strain EDL 933, found in toxinogenic E. coli O157 strains. Another EPEC-specific virulence determinant was also shown to be large plasmids harboring EPEC adherence factor sequences. The SLT-negative E. coli O157 strains described here fall under the heading of EPEC, which serves as an explanation for their virulence in infants, and represent a third pathogroup within serogroup O157.
Schmidt
H
H
Institut für Hygiene und Mikrobiologie, Universität Würzburg, Germany.
Rüssmann
H
H
Karch
H
H
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins; D003968:Diarrhea, Infantile / Q000382:microbiology*; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014774:Virulence
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli