Efficacy of a single oral dose of a live bivalent E. coli vaccine against post-weaning diarrhea due to F4 and F18-positive enterotoxigenic E. coli

Abstract

F4- and F18-positive enterotoxigenic E. coli strains (F4-ETEC and F18-ETEC) are important causes of post-weaning diarrhea (PWD) in pigs. F4 (antigenic variant ac) and F18 (ab and ac) fimbriae are major antigens that play an important role in the early stages of infection. Herein, the efficacy of a live oral vaccine consisting of two non-pathogenic E. coli strains, one F4ac- and one F18ac-positive, was evaluated using F4ac-ETEC and F18ab-ETEC challenge models. A randomized, masked, placebo-controlled, block design, parallel-group confirmatory study with two different vaccination-challenge intervals (7 and 21 days) was conducted for each challenge model. The vaccine was administered in one dose, to ≥18-day-old piglets via drinking water. Efficacy was assessed by evaluating diarrhea, clinical observations, weight gain and fecal shedding of F4-ETEC or F18-ETEC. Anti-F4 and anti-F18 immunoglobulins in blood were measured. The vaccination resulted in significant reductions in clinical PWD and fecal shedding of F4-ETEC and F18-ETEC after the 7- and 21-day-post-vaccination heterologous challenges, except for after the 21-day-post-vaccination F4-ETEC challenge, when the clinical PWD was too mild to demonstrate efficacy. A significant reduction of mortality and weight loss by vaccination were observed following the F18-ETEC challenge. The 7-day protection was associated with induction of anti-F4 and anti-F18 IgM, whereas the 21-day protection was mainly associated with anti-F4 and anti-F18 IgA. The 7-day onset and 21-day duration of protection induced by this vaccine administered once in drinking water to pigs of at least 18days of age were confirmed by protection against F4-ETEC and F18-ETEC, and induction of F4 and F18-specific immunity. Cross protection of the vaccine against F18ab-E. coli was demonstrated for both the 7- and 21-day F18-ETEC challenges.

Swine Enteric Colibacillosis in Spain: Pathogenic Potential of mcr-1 ST10 and ST131 E. coli Isolates

“…While ETEC neonatal diarrhea can be effectively controlled by vaccination of pregnant sows, passive protection is quickly lost after weaning ( Melkebeek et al, 2013 ; Matías et al, 2017 ). Currently, few vaccines are commercially available for PWD, and few provide protection against different E. coli pathotypes ( Nadeau et al, 2017 ; Won and John Hwa, 2017 ). In the present study, we performed a wide epidemiological study on a collection of E. coli isolates recovered from 464 faecal samples of enteric colibacillosis in pig production farms of Spain over a 10-year period to know the E. coli traits (pathotypes) presently implicated in swine diarrheas, and how the use of antibiotics (including colistin) could have affected the selection and emergence of resistant strains.…”

Maternal Vaccination. Immunization of Sows during Pregnancy against ETEC Infections

“…[ 61 , 62 ]. Coliprotec ® F4 (Prevtec Microbia GmbH, Montrela, Canada) [ 63 ] and the recently reported oral bivalent F4/F18 vaccine [ 64 ] are attenuated vaccines designed for the active immunization of pigs against PWD, but there are no data available on their effect in sows.…”

Growth Performance and Post-Weaning Diarrhea in Piglets Fed a Diet Supplemented with Probiotic Complexes

“…Post-weaning diarrhea (PWD) is the most common disease in weaned piglets and is a major economic problem worldwide. PWD is mainly caused by conditioned pathogens and enterotoxins, with a high incidence of intestinal microbiota disturbances [1,2]. Impaired gut microbiota composition after weaning can lead to slower growth, suggesting a greater permissiveness to pathogen colonization and induction of pro-inflammatory status.…”