The Efficacy Of Recombinant Strain Expressing The Major Protective Antigens Of Shiga-like Toxigenic Escherichia Coli Causing PWD/ED On Trial And Genotyping Of PWD/ED Suspected Pigs Bearing F18 Fimbria Receptors

Porcine edema disease(ED)and post-weaning diarrhoea(PWD)caused by Shiga-like toxigenic Escherichia coli are two of the most common mortality causes of recently weaned pigs. No effective methods for control of these two diseases are available. E. coli strains causing edema disease and/or post-weaning diarrhoea adhere to the small intestine by means of fimbria F4 (K88) or F18. Shiga-like toxin 2e (Stx 2e) is also produced by these organisms. Immunoprophylaxis of porcine edema disease and post-weaning diarrhoea caused by strains of Escherichia coli expressing fimbriae F18 and/or F4 is still an unsolved problem. A potential recombinant vaccine strain, BL21(pFSFaeG) to prevent ED and PWD was constructed by Shihui et al., which expressed two different subunits (FedA and FaeG) of both fimbriae, namely F18 and F4, and the subunit B of Shiga-like toxin 2e, using pGEX-6P-1 vector. Partly soluble 80kD GST-FedA-Stx2eB-FaeG fusion protein was expressed in recombinant strain BL21 (pFSFaeG) after induced by IPTG at 37℃, which was confirmed by SDS-PAGE and Western blotting analysis. 160 5-week-old mouse were immunized with live bacteria orally and with inactivated vaccine by the peritoneal route by Yang Jianmei, and the protection efficacy of vaccinated mice with inactivated recombinant strain BL21(pFSFaeG) against challenging of strain 107/86, C83907 and Stx 2e toxin was 81.8%,87.5% and 81.3% respectively.3-day-old piglets were divided into experimented group and control group...