Formalin-fixed human small intestinal mucosa possessing villi and lymphoid follicle epithelium of Peyer's patches at the mucosal surface was used to test the adherence ability of clinically isolated strains of Vibrio cholerae 01. V. cholerae 01 grown on CFA agar for-3 h at 37°C had various levels of cellular hemagglutinins (HAs) and manifested adherence abilities that were roughly correlated with the cellular HA levels, irrespective of cellular HA types. V. cholerae 01 adhered better to epithelium over ileal lymphoid follicles than to epithelium ofjejunal or ileal villi. Cells of different morphology which constituted lymphoid follicle epithelium were almost equal targets for adherence. In contrast, V. cholerae 01 grown on CFA agar for-20 h at 37C in many cases had lower levels of cellular HAs and adherence abilities. Contrary to the above observations with cellular HAs and adherence, piliation of V. cholerae 01 was rather more extensive at-20 h of incubation at 37°C than at-3 h of incubation at 37°C. L-Fucose inhibited adherence to a varied extent depending on the cellular HA types, while D-mannose enhanced adherence in some strains. Heating of V. cholerae 01 diminished adherence ability. This adherence model system provides a tool by which various V. cholerae 01 strains can be preliminarily tested for adherence ability and site in human small intestine.
Escherichia coli 73-1 (serotype O73:H33) and 5-2 (serotype O89:H؊) isolated from patients with diarrhea adhered to tissue culture cells (HeLa and HEp-2) as well as coverslips (plastic and glass) in a diffuse pattern. Adherence of strain 73-1 was mediated by a 110-kbp plasmid designated pEDA1 and correlated with Dmannose-resistant hemagglutinin (MRHA) detected with bovine, sheep, or human erythrocytes. The MRHA region was duplicated on pEDA1 and mediated the production of the 57-kDa outer membrane protein whose N-terminal amino acid sequence was hydrophobic. In accordance with MRHA and adherence, the 57-kDa outer membrane protein was observed best at 37؇C and to a lesser extent at 25؇C. In human intestine, adherence to mucus and colonic epithelium was obvious. No detectable pili were observed. The enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1) gene, whose nucleotide sequence was 99.1% homologous to that of enteroaggregative E. coli, was present adjacent to the MRHA region on pEDA1. Strain 5-2 also exhibited MRHA activities and adherence and had sequences corresponding to those of the MRHA region and EAST1 gene. The data suggest that strain 73-1 (and strain 5-2), which has characteristics of both diffusely adhering E. coli and enteroaggregative E. coli, possesses a novel hemagglutinin associated with diffuse adherence.
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