Evaluation of a live avirulent Escherichia coli vaccine for K88+, LT+ enterotoxigenic colibacillosis in weaned pigs.
Live, avirulent Escherichia coli vaccine strains were constructed and tested for efficacy in preventing colibacillosis in 4-week-old pigs. Either or both of 2 plasmids were inserted into avirulent E coli strain G58-1 (0101:NM). These plasmids were pPMC4, which encodes for LTb subunits of heat-labile enterotoxin, and pDHF1, which encodes for K88ac fimbriae. Litter- and weight-matched pigs were removed from sows when they were 10 days old and vaccinated orally with the constructed strains or with G58-1 (negative control vaccine) when they were 2 weeks old and 5 days later. All pigs were challenge-inoculated with virulent E coli strain 3030-2 (O157:K88, LT+, STb+) 2 weeks after the first vaccination. Only 1 pig vaccinated with G58-1/pPMC4/pDHF1 developed diarrhea and none died following challenge inoculation. Seventeen of 31 control pigs developed diarrhea and 11 died. Of 18 pigs vaccinated with G58-1/pDHF1 then challenge-inoculated with the virulent strain, 5 developed diarrhea and 2 died. Fifteen of 18 litter- and weight-matched controls developed diarrhea and 8 died. When compared with G58-1 (negative control), G58-1/pPMC4 afforded no protection to pigs challenge-inoculated with 3030-2.
Department of Veterinary Science, South Dakota State University, Brookings 57007.
D H
DH
Francis
J A
JA
Willgohs
D000818:Animals; D001428:Bacterial Vaccines; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000517:prevention & control / Q000662:veterinary*; D010861:Fimbriae, Bacterial; D010957:Plasmids; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control*; D014611:Vaccination / Q000662:veterinary*; D014613:Vaccines, Attenuated; D014774:Virulence
D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated