Effects of a siderophore receptor and porin proteins-based vaccination on fecal shedding of Escherichia coli O157:H7 in experimentally inoculated cattle.
The efficacy of a vaccine containing outer membrane siderophore receptor and porin (SRP) proteins for reducing fecal prevalence and shedding of Escherichia coli O157:H7 was evaluated in cattle inoculated with E. coli O157:H7. Thirty calves were randomly assigned to one of two groups, and on days 1 and 21 these calves were given subcutaneous injections of either a placebo (control) or the vaccine. Blood was collected weekly to monitor the serum anti-SRP antibody titers. Two weeks after the second vaccination, calves were orally inoculated with a mixture of five strains of nalidixic acid-resistant (NalR) E. coli O157:H7. Fecal samples and rectoanal mucosal swabs were collected daily for the first 5 days and then three times each week for the following 4 weeks to determine the presence and enumerate the fecal concentration of NalR E. coli O157:H7. At necropsy on day 35, gut contents and tissue swabs were collected to determine the presence and concentration of NalR E. coli O157:H7. Vaccinated cattle had significantly higher anti-SRP antibody titers than did control cattle, with a significant treatment x week interaction (P < 0.01). Vaccination of cattle with the SRP protein tended to decrease fecal concentration (1.9 versus 1.6 log CFU/g) of NalR E. coli O157:H7 (P = 0.10). The number of calves that were fecal culture positive for E. coli O157:H7 was lower (P = 0.05) in the vaccinated group than in the control group. The E. coli O157:H7 SRP vaccine tended to reduce fecal prevalence and concentration of E. coli O157:H7 in cattle orally inoculated with NalR E. coli 0157:H7 and may be a useful prehavest intervention strategy. Future research must be conducted on natural prevalence in feedlot operations to further evaluate the efficacy of this novel vaccine.
Thornton
A B
AB
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506-5606, USA.
Thomson
D U
DU
Loneragan
G H
GH
Fox
J T
JT
Burkhardt
D T
DT
Emery
D A
DA
Nagaraja
T G
TG
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology / Q000517:prevention & control*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000276:immunology*; D005243:Feces / Q000382:microbiology; D018272:Porins / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000276:immunology*; D014611:Vaccination
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D022361:Escherichia coli Vaccines; D018272:Porins; D011956:Receptors, Cell Surface; C035902:siderophore receptors