Commercial vaccine provides cross-protection by reducing colonization of salmonella enterica serovars infantis and hadar in turkeys

Authors: Bearson, Shawn; Monson, Melissa; Bearson, Bradley - Brad; WHELAN, SAMUAL - Oak Ridge Institute For Science And Education (ORISE); Byrd Ii, James - Allen; BURCIAGA, SELMA - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2023
Publication Date: 1/13/2024
Citation: Bearson, S.M., Monson, M.S., Bearson, B.L., Whelan, S.J., Byrd II, J.A., Burciaga, S. 2024. Commercial vaccine provides cross-protection by reducing colonization of salmonella enterica serovars infantis and hadar in turkeys. Vaccine. https://doi.org/10.1016/j.vaccine.2023.12.054.
DOI: https://doi.org/10.1016/j.vaccine.2023.12.054

Interpretive Summary: Foodborne illness due to the bacterium Salmonella continues to be a global problem for public health and food safety. Reducing Salmonella in our food supply (including meat) is challenging because the foodborne pathogen naturally lives in food-producing animals. Also, variability between groups of Salmonella strains (called serovars) means an animal’s immune response to one serovar may not fully protect against another serovar. Recently in the U.S., two human foodborne outbreaks occurred due to consumption of Salmonella-contaminated poultry products, caused by serovars Infantis and Hadar. Methods to limit the amount of Infantis and Hadar in turkeys as a method to reduce food product contamination are highly sought by producers. Thus, a commercial vaccine labeled for use in turkeys against Salmonella serovar Typhimurium was tested for its ability to reduce colonization of serovars Infantis and Hadar. Vaccination of young turkeys several weeks prior to exposure to either serovar Infantis or Hadar significantly reduced the amount of bacteria recovered from the gut when compared to birds that had not been vaccinated. Serovar Infantis was able to spread to the spleen and bone marrow of turkeys that had not been vaccinated, whereas vaccination significantly reduced Salmonella dispersal to these systemic sites. The data indicate that the serovar Typhimurium vaccine cross-protected turkeys against colonization with serovars Infantis and Hadar, illustrating that vaccination is an important intervention strategy to reduce Salmonella in turkeys.

Technical Abstract: Human foodborne outbreaks with antibiotic-resistant Salmonella enterica associated with contaminated poultry products have recently involved serogroup C serovars Infantis and Hadar. The current study evaluated a commercially available Salmonella vaccine for cross-protection against Infantis and Hadar serovars in turkeys. The live, attenuated S. Typhimurium (serogroup B) vaccine significantly reduced colonization of intestinal tissues (cecum, cecal tonsils, and cloaca) by serovars Infantis (C1) and Hadar (C2) and significantly limited systemic dissemination to the spleen. S. Infantis, but not S. Hadar, disseminated to bone marrow in non-vaccinated turkeys, but vaccination prevented S. Infantis dissemination to the bone marrow. The S. Infantis challenge strain contained the pESI megaplasmid, and virulence mechanism(s) residing on this plasmid may support dissemination and/or colonization of systemic niches such as myeloid tissue. Collectively, the data indicate that vaccinating turkeys with the serogroup B S. Typhimurium vaccine limited intestinal colonization and systemic dissemination by serogroup C serovars Infantis and Hadar.