Role of type 1 and type 3 fimbriae on the adherence and pathogenesis of Salmonella enteritidis in mice.

Through hemagglutination tests two isogenic strains of Salmonella enteritidis were shown to possess type 1 fimbriae (strain V) and type 1 and type 3 fimbriae (strain A). The two strains bound to human buccal and mouse small intestine epithelial cells. Strain A attached to the epithelial cells more readily and in larger numbers in comparison to strain V. Adherence of both strains were sensitive to the presence of D-mannose and pretreatment of the epithelial cells with tannic acid did not promote D-mannose resistant type binding of strain A S. enteritidis to human buccal and mouse small intestine epithelial cells. Furthermore, results from LD50 study indicated that, when the tests were carried out through oral inoculation of the mice the highly fimbriated stain A appeared to be more virulent. However, when the tests were carried out through intraperitoneal inoculation strain V was more virulent. These results indicate that adherence is a major contributing factor to the virulence of S. enteritidis and both type 1 and type 3 fimbriae contribute to this phenomenon.