title: Use of a siderophore receptor and porin proteins-based vaccine to control the burden of Escherichia coli O157:H7 in feedlot cattle.
abstract: OBJECTIVE
  To quantify the efficacy of a siderophore receptor and porin (SRP) proteins-based vaccine on the burden of Escherichia coli O157:H7 in feedlot cattle.
  
  
  METHODS
  Two research trials were conducted in field conditions. In each trial, cattle (n = 1252 in trial #1; n = 1284 in trial #2) were systematically divided into 20 pens and were administered either the E. coli O157 SRP vaccine or a placebo (trial #1: days 0 and 21; trial #2: days 0, 21, and 42). Rectal fecal samples were collected on day 0, and pen floor samples were collected on days 21, 35, 70, and 85 for trial #1 and on days 42 and 98 for trial #2. On day 85 of trial #1, rectoanal mucosal swab samples and hide swab samples were collected. Cattle were weighed on days 0, 21, and 85 (trial #1) or 1 week before harvest (trial #2).
  
  
  RESULTS
  In trial #1, prevalence of E. coli in the feces was lower in vaccinates compared to control animals (p = 0.04). On day 85, the likelihood of an animal being positive at any site was less among vaccinates than controls (p = 0.02). In trail #2, vaccination with SRP was associated with reduced shedding by 85.2% on day 98 (p < 0.01) but not on days 0 or 42. Vaccination with SRP was associated with a 98.2% reduction in concentration of E. coli O157 in fecal samples (2.54 vs. 0.80 log MPN/g of feces; p < 0.01). Cattle performance was not affected by SRP administration.
  
  
  CONCLUSIONS
  The E. coli O157:H7 SRP-based vaccine might serve as a preharvest intervention to reduce the burden of E. coli O157:H7 on cattle presented for harvest.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506, USA. dthomson@vet.ksu.edu
authors.forename: Daniel U
authors.initials: DU
authors.lastname: Thomson
authors.forename: Guy H
authors.initials: GH
authors.lastname: Loneragan
authors.forename: Ashley B
authors.initials: AB
authors.lastname: Thornton
authors.forename: Kelly F
authors.initials: KF
authors.lastname: Lechtenberg
authors.forename: Daryl A
authors.initials: DA
authors.lastname: Emery
authors.forename: Doug T
authors.initials: DT
authors.lastname: Burkhardt
authors.forename: Triuvoor G
authors.initials: TG
authors.lastname: Nagaraja
mesh_terms: D000375:Aging; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D057138:Bacterial Shedding; D001835:Body Weight; D002353:Carrier State / Q000175:diagnosis / Q000662:veterinary; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D004032:Diet; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000235:genetics / Q000254:growth & development* / Q000276:immunology / Q000302:isolation & purification; D022361:Escherichia coli Vaccines / Q000009:adverse effects; D005243:Feces / Q000382:microbiology; D005260:Female; D007413:Intestinal Mucosa / Q000382:microbiology; D008297:Male; D032541:Mass Vaccination / Q000662:veterinary; D018272:Porins / Q000276:immunology*; D015995:Prevalence; D011956:Receptors, Cell Surface / Q000276:immunology*; D012007:Rectum / Q000382:microbiology; D012306:Risk; D012867:Skin / Q000382:microbiology; D013223:Statistics as Topic; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001425:Bacterial Outer Membrane Proteins; D022361:Escherichia coli Vaccines; D018272:Porins; D011956:Receptors, Cell Surface; C035902:siderophore receptors