title: Virulence-defective strains of Salmonella enterica serovar Typhi as candidates for education at level 2 facilities.
abstract: The use of biosafety level 3 pathogens is an essential element of education and training at medical schools. We previously reported on invasion-defective strains of Salmonella enterica serovar Typhi, GTC 3P408 (DeltainvA, DeltasipB) and GTC 3P409 (DeltainvA, DeltasipB, and DeltaviaB), as candidates for use in educational programs. Vi negative strains of S. enterica serovar Typhi became extremely sensitive to complement attack but showed increased invasiveness. Therefore, this study was conducted to construct two virulencedefective strains, GTC 3P460 (DeltainvA, DeltasipB, and DeltarpoS) and GTC 3P461 (DeltainvA, DeltasipB, DeltaviaB, and DeltarpoS), of S. enterica serovar Typhi by deleting rpoS from the GTC 3P409 and GTC 3P408 strains. Stress tests demonstrated that GTC 3P460 and GTC 3P461 are sensitive to conditions of starvation, acid stress and oxidative stress. These results suggest that these virulence-defective strains have difficulty surviving in the gastric environment and in macrophages, characteristics that make them ideal candidates for education at level 2 facilities. Colony morphology and conventional biochemical features of these strains are identical to the parent strain S. enterica serovar Typhi GIFU 10007.
authors.affiliation: Department of Biochemistry and Molecular Biology, Jiangsu University School of Medical Technology, Jiangsu, Zhenjiang, China.
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Huang
authors.forename: Huaxi
authors.initials: H
authors.lastname: Xu
authors.forename: Mohammad Monir
authors.initials: MM
authors.lastname: Sha
authors.forename: Licheng
authors.initials: L
authors.lastname: Zhao
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Ohkusu
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ezaki
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics*; D001432:Bacteriology / Q000193:education; D004501:Education, Medical; D018384:Oxidative Stress; D011135:Polysaccharides, Bacterial / Q000276:immunology; D012485:Salmonella typhi / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D012808:Sigma Factor / Q000172:deficiency / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria