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Virulence‐Defective Strains of Salmonella enterica Serovar Typhi as Candidates for Education at Level 2 Facilities
Author(s) -
Huang Xinxiang,
Xu Huaxi,
Sha Mohammad Monir,
Zhao Licheng,
Ohkusu Kiyofumi,
Kawamura Yoshiaki,
Ezaki Takayuki
Publication year - 2006
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2006.tb03795.x
Subject(s) - biology , virulence , microbiology and biotechnology , salmonella enterica , serotype , salmonella typhi , virology , rpos , salmonella , bacteria , genetics , escherichia coli , gene , gene expression , promoter
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 (Δ invA , Δ sipB ) and GTC 3P409 (Δ invA , Δ sipB , and Δ viaB ), 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 virulence‐defective strains, GTC 3P460 (Δ invA , Δ sipB , and Δ rpoS ) and GTC 3P461 (Δ invA , Δ sipB , Δ viaB , and Δ rpoS ), 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.