Abstract
Salmonella enterica serovar Enteritidis (S. Enteritidis) is one of most common Salmonella serovars associated with human illness in the U.S. and worldwide. Surveillance from the U.S. National Antimicrobial Resistance Monitoring System indicates an increase in both chicken and human isolates of S. Enteritidis with decreased susceptibility to ciprofloxacin (DSC), a critical antibiotic prescribed for complicated human salmonellosis infections. S. Enteritidis reduction in chickens is a priority of poultry producers and public health agencies to improve food safety. In the current study, efficacy assessment of a live Salmonella vaccine (BBS 1134) revealed significant reduction of cecal and splenic colonization, and prevention of dissemination to the bone marrow by DSC S. Enteritidis in broiler chickens. Microbiome analysis indicated the cecal microbiota of vaccinated chickens is distinct compared to mock-vaccinated birds. The IDEXX SE Ab X2 Test did not detect antibodies to S. Enteritidis in vaccinated chicken serum, thereby permitting differentiation of infected from vaccinated animals (DIVA). Altogether, the Salmonella vaccine is a DIVA vaccine, afforded cross-protection, and significantly reduced intestinal colonization and dissemination to the spleen and bone marrow by DSC S. Enteritidis in chickens, thereby offering a prospective intervention for animal production to reduce food product contamination and improve food safety.
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Data availability
Raw 16S reads were uploaded to the NCBI Sequence Read Archive under BioProject PRJNA1309157.
Code availability
R scripts and full R session information with loaded libraries and their versions are located on GitHub (https://github.com/USDA-FSEPRU/bbs_1134_vaccine_vs_dsc_enteritidis_challenge.git).
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Acknowledgements
The authors are greatly appreciative of the outstanding technical support of Margaret Walker and Kellie Winter. We thank the Animal Research Unit staff for providing animal care. This work was supported by the United States Department of Agriculture (USDA), Agricultural Research Service (ARS) appropriated funds from CRIS projects 5030-32000-227-000D and 5030-31000-007-000-D. Funding for open access charge: USDA, ARS. This research utilized an appointment to the Agricultural Research Service Research Participation Program administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the U.S. Department of Energy (DOE) and the USDA. ORISE is managed by ORAU under DOE contract number DE-SC0014664. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendations or endorsement by the U.S. Department of Agriculture. The U.S. Department of Agriculture is an equal opportunity provider and employer.
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Conceptualization—S.M.D.B. and B.L.B; Investigation—B.L.B, S.J.W., M.P.N.E., D.P.N., M.S.M., C.L.A., and S.M.D.B.; Formal analysis—B.L.B, M.P.N.E., D.J.B., M.S.M., and S.M.D.B.; Methodology—B.L.B, S.J.W., M.P.N.E., D.J.B., M.S.M., C.L.A. and S.M.D.B.; Validation—B.L.B, M.P.N.E., D.J.B., M.S.M., C.L.A. and S.M.D.B.; Visualization—B.L.B, D.J.B., and M.S.M.; Data curation—B.L.B, D.J.B., S.J.W., M.P.N.E., and M.S.M.; Funding acquisition—S.M.D.B. and B.L.B; Project administration—S.M.D.B. and B.L.B; Resources—S.M.D.B.; Supervision—S.M.D.B. and B.L.B; Writing—original draft—B.L.B, S.J.W., M.P.N.E., D.J.B., M.S.M., and S.M.D.B.; Writing—review and editing—B.L.B, S.J.W., M.P.N.E., D.P.N., D.J.B., M.S.M., C.L.A., and S.M.D.B.
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Two patents (US 9,868,769 B2 and US 10,351,606 B2) have been issued for vaccine strain BBS 1134 with B.L.B. and S.M.D.B. indicated as inventors.
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Bearson, B.L., Whelan, S.J., Encinosa, M.P.N. et al. Chicken vaccination reduces colonization and dissemination of Salmonella serovar Enteritidis with decreased susceptibility to ciprofloxacin. npj Vaccines (2026). https://doi.org/10.1038/s41541-026-01414-y
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DOI: https://doi.org/10.1038/s41541-026-01414-y
