SP0454, A Putative Threonine Dehydratase, Is Required For Pneumococcal Virulence In Mice
WenJuan Yan, Hong Wang, WenChun Xu, KaiFeng Wu, Run Yao, XiuYu Xu, Jie Dong, YanQing Zhang, Wen Zhong, and XueMei Zhang*
Laboratory Medicine College, Key Laboratory of Diagnostic Medicine designated by the Ministry of Education, Chongqing Medical University, Chongqing 400016, P. R. China
Journal of Microbiology, 50(3),511-517, 2012,
Streptococcus pneumoniae, sp0454, colonization, virulence, adherence, invasion
Increasing pressure in antibiotic resistance and the requirement for the design of new vaccines are the objectives of clarifying the putative virulence factors in pneumococcal infection. In this study, the putative threonine dehydratase sp0454 was inactivated by erythromycin-resistance cassette replacement in Streptococcus pneumoniae CMCC 31203 strain. The sp0454 mutant was tested for cell growth, adherence, colonization, and virulence in a murine model. The Δsp0454 mutant showed decreased ability for colonization and impaired ability to adhere to A549 cells. However, the SP0454 polypeptide or its antiserum did not affect pneumococcal CMCC 31203 adhesion to A549 cells. The sp0454 deletion mutant was less virulent in a murine intranasal infection model. Real-time RT-PCR analysis revealed significant decrease of the pneumococcal surface antigen A expression in the sp0454 mutant. These results suggest that SP0454 contributes to virulence and colonization, which could be explained in part by modulating the expression of other virulence factors, such as psaA in pneumococcal infection.