EN
Pregnant sows were immunized against colibacillosis with 3 different commercial vaccines containning K88, K99, F41, and 987P fimbriae. E. coli strains isolated from the faeces of the newborn piglets were subsequently investigated for the presence of the mentioned fimbrial adhesins by the use of hemagglutination and slide agglutination tests. LT and STa enterotoxins were determined by ELISA and inhibition ELISA, respectively, using monoclonal antibodies. The results were compared with non — immunized controls. It was shown that all 3 vaccines used, had significant effect on the reduction of enterotoxigenic E. coli strains, with adhesive fimbriae, in newborn piglets. Only 2 out of 89 strains tested possessed K88 fimbriae whereas 18 and 10 strains isolated from control piglets (out of 83 strains examined) had K88 and K99 fimbrial adhesins, respectively. Only 1 strain isolated from immunized piglets was enterotoxigenic as compared to 40 enterotoxin-positive strains from control animals. These results show that immunization of sows with vaccines containing E. coli strains with adhesive fimbriae is effective in reducing the number of pathogenic E. coli strains in faeces of newborn piglets.