Issue |
Vet. Res.
Volume 41, Number 1, January-February 2010
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Number of page(s) | 14 | |
DOI | https://doi.org/10.1051/vetres/2009053 | |
Published online | 24 September 2009 | |
How to cite this article | Vet. Res. (2010) 41:05 |
DOI: 10.1051/vetres/2009053
Mutations in the Salmonella enterica serovar Choleraesuis cAMP-receptor protein gene lead to functional defects in the SPI-1 Type III secretion system
Zeng-Weng Chen1, 2, Shih-Ling Hsuan1, Jiunn-Wang Liao1, Ter-Hsin Chen1, 2, Chi-Ming Wu1, Wei-Cheng Lee1, Cheng-Chung Lin1, Chih-Ming Liao1, Kuang-Sheng Yeh3, James R. Winton4, Chienjin Huang2 and Maw-Sheng Chien 11 Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 250, Kuo Kuang Road, Taichung, 402, Taiwan, Republic of China
2 Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 250, Kuo Kuang Road, Taichung, 402, Taiwan, Republic of China
3 Department of Microbiology and Immunology, School of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
4 Western Fisheries Research Center, Seattle, Washington, USA
Received 21 May 2009; accepted 18 September 2009; published online 24 September 2009
Abstract - Salmonella enterica serovar Choleraesuis (Salmonella
Choleraesuis) causes a lethal systemic
infection (salmonellosis) in swine. Live attenuated Salmonella Choleraesuis
vaccines are effective in
preventing the disease, and isolates of Salmonella Choleraesuis with
mutations in the cAMP-receptor
protein (CRP) gene (Salmonella Choleraesuis crp) are the most widely used,
although the basis of the
attenuation remains unclear. The objective of this study was to determine if
the attenuated phenotype of
Salmonella Choleraesuis
crp was due to alterations in susceptibility to
gastrointestinal factors such as
pH and bile salts, ability to colonize or invade the intestine, or
cytotoxicity for macrophages. Compared
with the parental strain, the survival rate of Salmonella Choleraesuis
crp
at low pH or in the presence of
bile salts was higher, while the ability of the mutant to invade intestinal
epithelia was significantly
decreased. In examining the role of CRP on the secretory function of the
Salmonella pathogenicity island
1 (SPI-1) encoded type III secretion system (T3SS), it was shown that
Salmonella Choleraesuis
crp was
unable to secrete the SPI-1 T3SS effector proteins, SopB and SipB, which
play a role in Salmonella
intestinal invasiveness and macrophage cytotoxicity, respectively. In
addition, caspase-1 dependent
cytotoxicity for macrophages was significantly reduced in Salmonella
Choleraesuis
crp. Collectively,
this study demonstrates that the CRP affects the secretory function of SPI-1
T3SS and the resulting ability
to invade the host intestinal epithelium, which is a critical element in the
pathogenesis of Salmonella Choleraesuis.
Key words: Salmonella enterica serovar Choleraesuis / cAMP-receptor protein / CRP / type III secretion system / attenuation
Corresponding author: mschien@nchu.edu.tw cjhuang@nchu.edu.tw
© INRA, EDP Sciences 2009