Journal of Pure and Applied MicrobiologyVol. 8 No. 2

Attenuated Virulence and Protective Efficacy of a Vaccine with Multiple Mutated Salmonella enterica Serovar Typhimurium in Mouse

Youngjae Cho1*, Jisun Sun1, Iel Soo Bang2 and Tae-Wook Hahn1

1College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon - 200 701, Korea. 2Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju - 501 759, Korea.

Received on 12 September 2013 and accepted on 21 December 2013

 

ABSTRACT

Salmonella typhimurium is the causative agent of bacterial gastroenteritis in human via livestock products. S. typhimurium mutants (STD4 and STD5) deleted the hmpA, rpoS, ssrAB, aroA and ppk genes were constructed and, attenuated virulence and protective efficacy of the multiple mutants were evaluated in mice as a novel vaccine candidate. In the virulence test, CFUs of STD4 (hmpA, rpoS, ssrAB, and aroA) and STD5 recovered from the liver and spleen of the mice were highly decreased at the range of 2.40 to 5.51 logs for 15 days postinfection. The changes of organ/body weight ratios in mice were also showed same trends as the changes of CFUs in virulence test. In the protection test, CFUs of STD4 and STD5 recovered from the organs in mice were highly decreased compared to non-vaccination group. The Polyphospate kinase (ppk) gene was not associated with protective efficacy but attenuated virulence in S. typhimurium mutant. Our results indicated that STD4 and STD5 firstly developed in this study showed highly attenuated virulence and protective efficacy. This work shows that S. typhimurium mutant deleted the multiple genes provide a basis for further development of a novel vaccine.

Keywords : Live attenuated vaccine, protective efficacy, Salmonella Typhimurium.