Recoveries of strain EC34195nal
from organs of turkeys vaccinated with a formalin-inactivated bacterin formulated with different adjuvants at 24 h post-challenge. Turkey poults were given sterile saline (negative control), an EC34915-based inactivated bacterin without adjuvant, or formulated with adjuvants that promote a Th1 response (CASAC or CpG-oligonucleotides (A)), or Th2 response (Titermax® Gold or aluminium hydroxide (B)). All vaccines were given by the subcutaneous route at 1 day-old and boosted at day 14. All the birds were challenged at day 41 post-primary vaccination via the intra-airsac route with EC34195nalR and sampled after 24 h. The data are presented as mean log10 CFU/g tissue ± standard error of the mean. APEC-specific serum IgY levels for corresponding birds at post-mortem examination were measured by ELISA compared to mock- and bacterin-vaccinated groups, Th1- (C) and Th2-stimulating adjuvants (D). + denotes value of EC34195nalR after enrichment. “a” denotes P ≤ 0.05 relative to turkey poults that received sterile saline (mock-vaccinated group), “b” denotes P ≤ 0.05 relative to bacterin alone, and “ab” is significance relative to both mock- and bacterin-vaccinated groups.