An Atypical Adherence Pattern of Enterohemorrhagic Escherichia coli Strains Belonging to Serotypes 0128: H2 and 0128:H12

S ummary. Shiga toxin 1 [Stxl]and Stx2-producing enterohemorrhagic Escherichia coll (EHEC) strains belonging to serotypes 0128:H2 and 0128:H12 adhered in a pattern of chains to HCT-8 and HEp-2 cells as well as plastic or glass coverslips. Scanning electron microscopic examination sharply distinguished this adherence pattern from those of EHEC 0157:H7 and enteroaggregative E. coli (EAggEC). The 0128:H2 and 0128: H12 strains possessed rigid pili of a diameter of ca. 6 nm and exhibited D-mannose-resistant hemagglutinating activities against horse and guinea pig erythrocytes. These strains were negative in a fluorescent-actin staining (FAS) assay and the gene sequence (eae) for an attaching and effacing lesion was absent. The strains were also negative for EAggEC in DNA assay. The data suggest that the EHEC 0128:H2 and 0128:H12 strains possess a putative atypical adherence factor responsible for colonization of the human intestine.