Osong Public Health Res Perspect.  2012 Dec;3(4):222-228. 10.1016/j.phrp.2012.10.002.

Enhanced Type III Secretion System Expression of Atypical Shigella flexneri II:(3)4,7(8)

• Hong S
• Cha I
• Kim NO
• Kim SH
• Jung KT
• Lee JH
• Kim DW
• Park MS
• Kang YH

• KMID: 2518048
• DOI: http://doi.org/10.1016/j.phrp.2012.10.002

Abstract

Objectives
We aimed at evaluating the virulence of atypical Shigella flexneri II:(3)4,7(8) by DNA microarray and invasion assay.
Methods
We used a customized S. flexneri DNA microarray to analyze an atypical S. flexneri II:(3)4,7(8) gene expression profile and compared it with that of the S. flexneri 2b strain.
Results
Approximately one-quarter of the atypical S. flexneri II:(3)4,7(8) strain genes showed significantly altered expression profiles; 344 genes were more than two-fold upregulated, and 442 genes were more than 0.5-fold downregulated. The upregulated genes were divided into the category of 21 clusters of orthologous groups (COGs), and the “not in COGs” category included 170 genes. This category had virulence plasmid genes, including the ipa-mxi-spa genes required for invasion of colorectal epithelium (type III secretion system). Quantitative reverse-transcription polymerase chain reaction results also showed the same pattern in two more atypical S. flexneri II:(3)4,7(8) strains. Atypical S. flexneri II:(3)4,7(8) showed four times increased invasion activity in Caco-2 cells than that of typical strains.
Conclusion
Our results provide the intracellularly regulated genes that may be important for adaptation and growth strategies of this atypical S. flexneri.

Keyword

atypical; microarray; Shigella