title: Increased efficacy of inactivated vaccine candidates prepared with Salmonella enterica serovar Typhimurium strains of predominant genotypes in ducks.
abstract: Salmonella enterica serovar Typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. In particular, ducks serve as a reservoir of serovar Typhimurium, and are one of the common sources of human infection. To prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. Here, we analyzed the genetic diversity and virulence of serovar Typhimurium isolates from ducks in Korea to identify the predominant strains that might be used as efficient vaccine candidates for ducks. Among the isolates, 2 representative isolates (ST26 and ST76) of predominant genotypes were selected as vaccine strains on the basis of genotypic analysis by pulsed-field gel electrophoresis and DNA microarrays. Two-week-old ducks were then injected intramuscularly with inactivated vaccine candidates prepared using ST26 or ST76 (10(8) cfu/0.5 mL/duck or 10(9) cfu/0.5 mL/duck), and oral challenge with a highly virulent serovar Typhimurium strain (10(9) cfu/0.5 mL/duck) was carried out 2 wk later. Shedding of the challenge strain was significantly decreased in group 2 after vaccination. The antibody levels by enzyme-linked immunosorbent assay in all vaccinated groups were enhanced significantly (P < 0.05) compared to the unvaccinated control group. Overall, vaccination with ST26 or ST76 reduced bacterial shedding and colonization in internal organs, and induced elevated antibody response. In particular, serovar Typhimurium ST26 (10(8) cfu/0.5 mL/duck) was the most effective vaccine candidate, which can provide efficient protection against serovar Typhimurium in ducks with higher effectiveness compared to a commercial vaccine currently used worldwide.
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Youn
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: Y K
authors.initials: YK
authors.lastname: Kwon
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Konkuk University, Gwangjin-gu, Seoul 143-701, Korea.
authors.forename: C S
authors.initials: CS
authors.lastname: Song
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: O M
authors.initials: OM
authors.lastname: Jeong
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: B K
authors.initials: BK
authors.lastname: Choi
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea.
authors.forename: S C
authors.initials: SC
authors.lastname: Jung
authors.affiliation: Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Anyang, Gyeonggi 430-757, Korea kangmskr@korea.kr.
authors.forename: M S
authors.initials: MS
authors.lastname: Kang
mesh_terms: D000818:Animals; D004372:Ducks / Q000276:immunology / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D020411:Oligonucleotide Array Sequence Analysis; D011201:Poultry Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D012485:Salmonella typhi / Q000235:genetics / Q000276:immunology*; D014436:Typhoid-Paratyphoid Vaccines / Q000627:therapeutic use*; D015164:Vaccines, Inactivated / Q000627:therapeutic use
chemical_list: D014436:Typhoid-Paratyphoid Vaccines; D015164:Vaccines, Inactivated
keywords: Salmonella; Typhimurium; duck; genotype; vaccine