The Campylobacter jejuni Response Regulator, CbrR, Modulates Sodium Deoxycholate Resistance and Chicken Colonization

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Raphael, Brian
Pereira, Sonia
Flom, Gary
Zhang, Qijing
Ketley, Julian
Konkel, Michael
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Zhang, Qijing
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Veterinary Microbiology and Preventive Medicine
Our faculty promote the understanding of causes of infectious disease in animals and the mechanisms by which diseases develop at the organismal, cellular and molecular levels. Veterinary microbiology also includes research on the interaction of pathogenic and symbiotic microbes with their hosts and the host response to infection.
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Veterinary Microbiology and Preventive Medicine

Two-component regulatory systems play a major role in the physiological response of bacteria to environmental stimuli. Such systems are composed of a sensor histidine kinase and a response regulator whose ultimate function is to affect the expression of target genes. Response regulator mutants of Campylobacter jejuni strain F38011 were screened for sensitivity to sodium deoxycholate. A mutation in Cj0643, which encodes a response regulator with no obvious cognate histidine kinase, resulted in an absence of growth on plates containing a subinhibitory concentration of sodium deoxcholate (1%, wt/vol). In broth cultures containing 0.05% (wt/vol) sodium deoxycholate, growth of the mutant was significantly inhibited compared to growth of the C. jejuni F38011 wild-type strain. Complementation of the C. jejuni cbrR mutant in trans restored growth in both broth and plate cultures supplemented with sodium deoxycholate. Based on the phenotype displayed by its mutation, we designated the gene corresponding to Cj0643 as cbrR (Campylobacter bile resistance regulator). While the MICs of a variety of bile salts and other detergents for the C. jejuni cbrR mutant were lower, no difference was noted in its sensitivity to antibiotics or osmolarity. Finally, chicken colonization studies demonstrated that the C. jejuni cbrR mutant had a reduced ability to colonize compared to the wild-type strain. These data support previous findings that bile resistance contributes to colonization of chickens and establish that the response regulator, CbrR, modulates resistance to bile salts in C. jejuni.


This article is published as Raphael, Brian H., Sonia Pereira, Gary A. Flom, Qijing Zhang, Julian M. Ketley, and Michael E. Konkel. "The Campylobacter jejuni response regulator, CbrR, modulates sodium deoxycholate resistance and chicken colonization." Journal of bacteriology 187, no. 11 (2005): 3662-3670. doi: 10.1128/JB.187.11.3662-3670.2005. Posted with permission.

Sat Jan 01 00:00:00 UTC 2005