Adherence targets of Vibrio parahaemolyticus in human small intestines

Formalin-fixed human small intestinal mucosa with mucus coating, villi, and lymphoid follicle epithelium at the mucosal surface was used to test the adherence sites of clinically isolated (Kanagawa phenomenon-positive) strains of Vibrio parahaemolyticus. V. parahaemolyticus strains grown on CFA agar (supplemented with 3% NaCl) for ca. 3 h at 37 degrees C possessed various levels of cell-associated hemagglutinins (HAs) which were detected with human or guinea pig erythrocytes. The observed adherence abilities of V. parahaemolyticus strains to human small intestinal mucosa correlated roughly with the HA levels of the strains. Under the test conditions, ileal lymphoid follicle epithelium (especially M cells) provided the best adherence target for V. parahaemolyticus. Adherence to villus absorptive cells or to mucus coating was observed at lower levels. In addition, all 3-h-grown V. parahaemolyticus strains tested produced high levels of HAs as detected with rabbit erythrocytes. The strains were all strikingly motile. In contrast, V. parahaemolyticus strains grown on CFA agar (supplemented with 3% NaCl) for ca. 20 h at 37 degrees C had much lower levels of HAs, adherence abilities, and motility. In contrast to the above observations, piliation of V. parahaemolyticus was more extensive at ca. 20 h of incubation at 37 degrees C than at ca. 3 h of incubation at 37 degrees C. The remarkable ability of V. parahaemolyticus to adhere to lymphoid follicle epithelium was also confirmed by using rabbit small intestinal mucosa.