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PLoS One. 2014 Aug 11;9(8):e104313. doi: 10.1371/journal.pone.0104313. eCollection 2014.

Characterization of BPSS1521 (bprD), a regulator of Burkholderia pseudomallei virulence gene expression in the mouse model.

Author information

1
Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand; Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
2
Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand.
3
National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand.
4
Biofilm Research Group, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
5
Department of Pathobiology, SVM, University of Wisconsin, Madison, Wisconsin, United States of America.
6
Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand; Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
7
Department of Microbial Pathogenesis, School of Dentistry, University of Maryland-Baltimore, Baltimore, Maryland, United States of America.

Abstract

The Gram-negative saprophytic bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a severe infectious disease of both humans and animals. Severity of the disease is thought to be dependent on both the health status of the host, including diabetes mellitus and kidney disease, and bacterial-derived factors. To identify the bacterial factors important during an acute infection, gene expression profiles in the spleen, lung, and liver of BALB/c (Th2 prototype) and C57BL/6 mice (Th1 prototype) were determined using DNA microarrays. This analysis identified BPSS1521 (bprD), a predicted transcriptional regulator located in the type III secretion system (T3SS-3) operon, to be up regulated, specifically in C57BL/6 mice. BALB/c mice infected with a bprD mutant showed a shorter time to death and increased inflammation, as determined by histopathological analysis and enumeration of bacteria in the spleen. Elevated numbers of multinucleated giant cells (MNGCs), which is the hallmark of melioidosis, were detected in both the wild-type and the bprD mutants; a similar elevation occurs in melioidosis patients. One striking observation was the increased expression of BPSS1520 (bprC), located downstream of bprD, in the bprD mutant. BprC is a regulator of T6SS-1 that is required for the virulence of B. pseudomallei in murine infection models. Deletion of bprD led to the overexpression of bprC and a decreased time to death. bprD expression was elevated in C57BL/6--as compared to BALB/c--mice, suggesting a role for BprD in the natural resistance of C57BL/6 mice to B. pseudomallei. Ultimately, this analysis using mice with different immune backgrounds may enhance our understanding of the outcomes of infection in a variety of models.

PMID:
25111708
PMCID:
PMC4128674
DOI:
10.1371/journal.pone.0104313
[Indexed for MEDLINE]
Free PMC Article

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