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Updated: Jun 23, 2026

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
Published on: February 23, 2014
[Effect of clpE gene deletion on virulence of Streptococcus pneumoniae]
Qun Zhang1, Nanlin Yin, Wenchun Xu
1Key Laboratory of Medical Diagnostics, Ministry of Education, Chongqing Medical University, Chongqing 400016, China. zhangqun198166@163.com
Objective:
To study the effect of clpE gene deletion on the virulence of Streptococcus pneumoniae.
Methods:
The clpE-deficient strain was constructed by LFH-PCR and identified by PCR and sequencing. The impact of clpE mutant on the virulence of S. pneumoniae was evaluated in a mouse model. In addition,we also studied the effect of clpE mutant on adherence and invasion of host cells. Real time RT-PCR was used to measure the mRNA expression levels of autolysin A, pneumococcal surface adhesion A, pneumolysin, pneumococcal surface protein A and neuraminidase.
Results:
The clpE gene was replaced completely by erm cassette. Mice virulence experiments showed that the median lethal time of the wide-type was 54 h, whereas that of clpE mutant was 21d (P < 0.01). Cell culture infection experiments indicated that adherence and invasion of clpE mutant were strongly reduced (P < 0.05). The expression of virulent factors in clpE mutant was lower than that of the wild-type (P < 0.05).
Conclusion:
ClpE is involved in virulence by modulating the expressions of virulence factors.
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