SALMONELLA-ENTERICA VAR TYPHIMURIUM AND SALMONELLA-ENTERICA VAR ENTERITIDIS EXPRESS TYPE-1 FIMBRIAE IN THE RAT IN-VIVO

In a series of experiments rats were dosed with purified type 1 fimbri ae from Salmonella enterica var Enteritidis or with fimbriated culture s of either S. enterica var Typhimurium or S. enterica var Enteritidis , Paraffin-wax embedded histological sections of jejunal and ileal tis sue were taken and stained by the streptavidin biotin complex (sABC) s taining technique for the detection of salmonella and type 1 fimbriae. On oral infection with Enteritidis and Typhimurium both bacteria were shown to be closely associated with the rat ileal epithelium and expr essed type 1 fimbriae, thus clearly demonstrating that type 1 fimbriae are expressed by salmonellae in vivo. Moreover, association with the ileum was also shown to occur when purified type 1 fimbriae were orall y administered to rats. Our results suggest that type 1 fimbriae alone or in combination with other fimbriae may play an important role in t he early stages of infection with these pathogenic bacteria.