|SANCHEZ-INGUNZA, ROXANA - Former ARS Employee|
|ICARD, ALAN - University Of Georgia|
Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2015
Publication Date: 7/21/2015
Citation: Guard, J.Y., Sanchez-Ingunza, R., Icard, A. 2015. Reduction of Salmonella Enteritidis in the spleens of hens by bacterins that vary in fimbrial protein SefD. Foodborne Pathogens and Disease. 12(10):836-843.2015.
Interpretive Summary: We used information obtained from previous whole genome analysis of Salmonella Enteritidis to select the protein SefD for use in a killed vaccine (bacterin). We wanted to know if its inclusion would improve protection of hens against invasive strains of Salmonella Enteritidis. Salmonella Enteritidis is the world’s leading cause of food-borne salmonellosis. Countries differ in their approach to vaccination of hens, in part because of the perception that vaccines are only partially protective and do not warrant the cost of vaccination. The presence of the protein SefD significantly reduced recovery of Salmonella from the spleens of hens. In summary, it is possible to improve the performance of vaccines intended to reduce organ invasion in hens by Salmonella Enteritidis, which is a property of strains that result in egg contamination.
Technical Abstract: Gene sefD is part of operon sefABCD, and it is required for production of the SEF14 fimbria by Salmonella Enteritidis. We compared strains that varied in SefD content for their ability to reduce recovery of Salmonella Enteritidis from the spleens of hens infected by parenteral challenge. The two bacterins had either no SefD due to a mutation in sefD or produced high levels due to a complementing plasmid. Leghorn hens were vaccinated twice subcutaneously with each bacterin, and then challenged intramuscularly with 6.4 ± 0.46 x 107 CFU of bacteria 4 weeks after the second immunization. Control groups included infected non-vaccinated hens, vaccinated uninfected hens, and uninfected non-vaccinated hens. A third trial was conducted twice to evaluate the impact of adjuvant on results, and aluminium hydroxide gel had fewer side effects than water-in-oil. At 21 days post-infection, Salmonella was recovered on average from 68.0%, 53.3% and 82.0% of spleens from groups vaccinated with SefD- bacterin, SefD+ bacterin, and unvaccinated controls, respectively. The presence of SefD significantly and consistently reduced recovery from spleens throughout all trials. These results suggest that SefD, and perhaps the complete fimbria SEF14, may improve efficacy of immunotherapy of hens intended to reduce Salmonella Enteritidis and its association with eggs.