Current Research and Development for Vaccination against E. coli O157:H7. RMC 2004 June 22, 2004 Dr. Joyce Van Donkersgoed

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1 Current Research and Development for Vaccination against E. coli O157:H7 RMC 2004 June 22, 2004 Dr. Joyce Van Donkersgoed

2 Outline E. coli O157:H7 in cattle Goals of pre-harvest control Ideal vaccine Experimental challenge studies Controlled field trials Summary

3 E. coli O157:H7 Prevalence Cattle feces, hide, mouth, rumen ubiquitous endemically unstable seasonal variable over time and pens (0% - 80%) many subtypes Broad agro-ecological niche Feces 60.4% Hock 41.7% Flank 54.0% Back 74.1% Ventrum 51.1% Mouth 74.8% (Keen & Elder, 2002)

4 Fecal/hide prevalence correlated with carcass contamination Role Role for pre- harvest interventions E. coli O157:H7

5 Pre-harvest interventions Effective statistical vs clinical relevance reliable Practical on farm implementation Compliance issue Benefit carry through to slaughter Cost-benefit Beef producer Processor

6 Ideal E. coli O157 vaccine Consistently effective in reducing frequency, duration and amount of E. coli O157:H7 shed in feces and on hides Protective against many O157 subtypes and other EHEC

7 Ideal E. coli O157 vaccine Practical vaccine regime that fits existing management strategies Safe Easy to administer, stable during transport/storage Valuable to beef producer No clinical disease Business risk management tool food safety environment Cost

8 Vaccines for E. coli O157:H7 UBC/VIDO supernatant vaccine Ft. Dodge bacterin E. coli O157:H7 intimin expressed by transgenic plant cells in an oral vaccine AMI Research Courtesy B. Finlay

9 Intimin Bacterial Cell EspA Host Cell Tir

10 Immune Response to Infection Titre LPS Tir EspA Intimin Day Post Infection

11 Experimental Challenge Study Protocol Daily Fecals Vaccinate Bleed Vaccinate Bleed Bleed Challenge

12 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP Trial 1 Old Calves 6-Month-Old Calves 8 Vaccinates, 8 Placebo Controls Vaccine at 200 µg/ dose with oil-in in- water adjuvant Two doses, 21-days apart Challenged with 10 8 CFU E. coli O157:H7 by oral-gastric intubation at 14 days

13 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP Trial 1: Shedding Data (65% Reduction in Days E. coli Shed) Average Days Shed Post Challenge Placebo EHEC Vaccine

14 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP 1: Average & Median Shedding Titers (83-92% Reduction in E coli CFUs Shed) Median CFU Shed Average CFUs Shed Placebo EHEC Vaccine

15 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP Trial 2 Yearling Cattle 13 Vaccinates, 25 Placebo Controls Vaccine at 50 µg/ dose with oil-in in-water adjuvant Three doses a 0, 21, & 35 days Challenged with 10 8 CFU E. coli O157:H7 by oral-gastric intubation at 14 days

16 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge Days Shedding POP 2: Shedding Data (90% Reduction in Days E. coli Shed) Placebo EHEC

17 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP 2: Daily Shedding Data Log 10 CFUs Shed Placebo EHEC Days Post Challenge

18 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge 2500 POP 2: Average & Median Shedding Titers (95-100% Reduction in Avg. CFUs Shed) Placebo Vaccine Median Average

19 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP 2: Tir Serology EHEC Placebo GMT Prebleed Tir Boost 1 Boost 2 Challenge

20 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge POP 2: EHEC Serology Vaccine Placebo GMT Prebleed EHEC Boost 1 Boost 2 Challenge

21 E. coli O157:H7 Secretory Proteins UBC Vaccine & VIDO Challenge GMT POP 2: EspA Serology Vaccine Placebo Prebleed Boost 1 Boost 2 Challenge

22 E. coli O157:H7 Secretory Proteins Bioniche Vaccine &VIDO Challenge Production Vaccine Experimental Trial 2 6-Month-Old Calves 8 Vaccinates, 8 Placebo Controls Vaccine with oil-in in-water adjuvant Three doses a 0, 21, & 42 days Challenged with 10 8 CFU E. coli O157:H7 by oral-gastric intubation at 14 days

23 E. coli O157:H7 Secretory Proteins Bioniche Vaccine &VIDO Challenge Total Days Shed Days 3-14 Post Challenge (16-18% Reduction which is not significant) Total Days Shed BNC1 BNC2 Placebo

24 E. coli O157:H7 Secretory Proteins Bioniche Vaccine &VIDO Challenge 40,000 Average CFUs Shed Post Challenge (95-98% Reduction) 37,881 Average CFUs 30,000 20,000 10, ,985 BNC1 BNC2 Placebo

25 E. coli O157:H7 Secretory Proteins Bioniche Vaccine &VIDO Challenge Log Total CFUs Shed Total E. coli Shed (Log-10) Days 3-14 Post Challenge (95-98% Reduction) Vaccine H Vaccine I Placebo

26 University of NE Vaccine Studies UBC vaccine (supernatant proteins containing type III secreted proteins from ECO157, adjuvant VSA3) 2002 Trial 12 pens of 8 animals/rx; 105 DOF Vaccinated with 3 doses, 3 wk apart

27 University of NE Vaccine Studies Vaccinated cattle had a significant (P<0.05) increase in antibody levels (Esp( B, Tir, O157) Vaccination reduced fecal prevalence of ECO157 from 21.3% to 8.8% (vaccine 59% effective, p = 0.04) Ref: Vaccine 2004; 22:

28 University of NE Vaccine Studies 2003 Study Bioniche vaccine (same antigen as UBC, but different adjuvant) 60 pens, 4 treatments per pen of 8 cattle 0, 1, 2 or 3 vaccine administered at 3 wk intervals to animals within each pen 12 external control pens (no vaccine) 126 DOF

29 University of NE Vaccine Studies Cattle receiving either 1, 2 or 3 doses of vaccine were less likely to shed O157:H7 during the post- vaccination period than untreated pens (OR=0.33, p=0.0008) Vaccine efficacy: 59% Herd Immunity?

30 Canadian Feedlot Trial October 2001 to December feedlots in Alberta and 1 feedlot in SK One-time holding capacities ranged from 10,000 head to 35,000 head Average pen size 250 head Total 218 pens on trial, ranging from 10 to 42 pens per feedlot

31 Feedlot Vaccination Protocol Pens within a feedlot randomly allocated to one of two vaccines (blind) E. coli O157:H7 vaccine contained secreted proteins (Tir, Esps) ) at 25 ug/ml Placebo was the same vaccine without the antigen 2 ml given SC in neck at arrival processing and at re- implanting All cattle within a pen received the same vaccine (unit of analysis: pen)

32 Sampling 10 grams of feces collected from 30 fresh manure patties within each feedlot pen at arrival processing, revaccination (re- implanting) and within 2 weeks of slaughter Placed in transport media and couriered to lab Fecal samples cultured after immunomagnetic enrichment In 2 feedlots, serum samples collected from 50 vaccinates and 50 controls for ELISA

33 Median ELISA in Feedlot 1 Titer change EHEC (1 st vac) EHEC (slaughter) Tir (1 st vac) Tir (slaughter) Control Vaccinated P value < < < <0.0001

34 Median ELISA in Feedlot 2 Titer change EHEC (1 st vac) EHEC (slaughter) Tir (1 st vac) Tir (slaughter) Control Vaccinated P value

35 Proportion of feedlot pens positive and mean within pen prevalence by ECO157 vaccine and sampling time % positive pens Control Vaccine Mean (SE) within pen prevalence % Control Vaccine N pens Arrival processing Pre- slaughter Re- vaccination (1.0) 5.5 (1.2) 6.6 (1.3) 2.2 (0.6) 4.9 (1.1) 6.1 (1.4)

36 Vaccine Efficacy? Formalin alteration of epitopes Different adjuvant Vaccine doses and interval Challenge Lower prevalence Highly variable prevalence Larger pen size Longer days on feed

37 CSU: Vaccine Study (Fort Dodge Bacterin) Vaccinated twice, 30 days apart 3 pens/vaccine (200 yearlings/pen) 90 DOF Vaccine reduced E. coli O157 prevalence on hides from 40% to 20% and in feces from 46% to 15% Ref: Ransom J, Belk K. NCBA June 2003

38 Summary ECO157 vaccines can induce an immunological response Efficacy demonstrated but effect not consistent Work best in high prevalence pens Additional controlled field trial research required in commercial feedlot settings before recommended effective pre-harvest intervention Research should carry affect through to processing plant

39 Acknowledgments Dr. Andy Potter, VIDO Dr. Dragan Rogan, Bioniche Dr. David Smith, U of NE Dr. Keith Belk, U of CO