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 Chen, Shih Ling Hsuan, Jiunn Wang Liao, Ter Hsin Chen, Chi Ming Wu, Wei Cheng Lee, Cheng Chung Lin, Chih Ming Liao, Kuang Sheng Yeh, James R. Winton, Chienjin Huang, Maw Sheng Chien

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19 Citations (Scopus)

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 δ 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 δcrp 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 δcrp 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 δcrp 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 δcrp. 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.

Original languageEnglish
JournalVeterinary Research
Volume41
Issue number1
DOIs
Publication statusPublished - Jan 2010

Keywords

  • Attenuation
  • CAMP-receptor protein
  • CRP
  • Salmonella enterica serovar Choleraesuis
  • Type III secretion system

ASJC Scopus subject areas

  • veterinary(all)

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    Chen, Z. W., Hsuan, S. L., Liao, J. W., Chen, T. H., Wu, C. M., Lee, W. C., Lin, C. C., Liao, C. M., Yeh, K. S., Winton, J. R., Huang, C., & Chien, M. S. (2010). Mutations in the Salmonella enterica serovar Choleraesuis cAMP-receptor protein gene lead to functional defects in the SPI-1 Type III secretion system. Veterinary Research, 41(1). https://doi.org/10.1051/vetres/2009053