David R. Hendrixson, Ph.D.
Assistant Professor of Microbiology

Office: 214-648-5949
Fax: 214-648-5905
Email: david .hendrixson@utsouthwestern.edu

Campylobacter jejuni is a leading cause of bacterial gastroenteritis in the United States and other developed countries throughout the world.  C. jejuni disease is usually characterized by an inflammatory gastroenteritis of the colon and rectum ranging from a mild to bloody diarrheal syndrome frequently accompanied by fever and abdominal cramping. In contrast to humans, many animals - especially avian species - are natural hosts for C. jejuni and harbor the organism in the gastrointestinal tract without symptomatic disease. Contaminated poultry meats represent a significant source of C. jejuni that impacts human health. The C. jejuni determinants and host factors that lead to the development of disease in humans or a commensal relationship in animal are not adequately understood.

A major focus of our laboratory is to identify virulence and colonization factors of C. jejuni that allow for interactions with appropriate hosts. Furthermore, we have developed unique genetic tools to examine the genetic regulation of expression of these important factors. Currently, we are defining molecular and genetic events in C. jejuni that contribute to the development of the flagellar organelle and capsular polysaccharide production.

The most common source for C. jejuni in sporadic cases of disease involves handling or consuming contaminated poultry products, including meats derived from the slaughtering of chickens infected with C. jejuni. We are currently studying the specific host and bacterial interactions that occur between C. jejuni and avian host in order to understand how commensalism is established between the two species and to provide insight into interactions that may occur differently between the bacterium and human hosts that lead to disease. We are using a broad approach involving analyses of bacterial colonization of host tissues, host response to infection, and interactions with components of innate immunity to further our understanding of these events.

Overall, the research interests in our laboratory include broad goals in determining pathogenic and commensal mechanisms of C. jejuni enabling it to survive in various hosts. These projects combined should provide interesting insights into developments occurring between the bacterium and each host resulting in the ability of C. jejuni to undertake two different personalities - one as a commensal and one as a pathogen. We hope that the results of these projects will provide a more complete understanding of C. jejuni and the impact this organism has in both human health and commensalism in the agricultural community.

Recent Publications

Stephanie N. Joslin and David R. Hendrixson, "Analysis of the Campylobacter jejuni FlgR Response Regulator Suggests Integration of Diverse Mechanisms to Activate an NtrC-Like Protein" Journal of Bacteriology, 190:2422-2433, 2008

Lacey K. Bingham-Ramos and David R. Hendrixson, "Characterization of Two Putative Cytochrome C Peroxidases of Campylobacter jejuni Involved in Promoting Commensal Colonization of Poultry" Infection and Immunity, 76:1105-1114, 2008

Shawn M. Sommerlad and David R. Hendrixson, "Analysis of the Roles of FlgP and FlgQ in Flagellar Motility of Campylobacter jejuni" Journal of Bacteriology, 189:179-186, 2007

David R. Hendrixson, "A Phase-Variable Mechanism Controlling the Campylobacter jejuni FlgR Response Regulator Influences Commensalism" Molecular Microbiology, 61:1646-1659, 2006

David R. Hendrixson and Victor J. DiRita, "Identification of Campylobacter jejuni Genes Involved in Commensal Colonization of the Chick Gastrointestinal Tract" Molecular Microbiology, 52:471-484, 2004

Significant Publications

David R. Hendrixson and Victor J. DiRita, "Transcription of sigma54-dependent but not sigma28-dependent Flagellar Genes in Campylobacter jejuni is Associated with Formation of the Flagellar Secretory Apparatus" Molecular Microbiology, 50:687-702, 2003

David R. Hendrixson, Brian J. Akerley, and Victor J. DiRita, "Transposon Mutagenes of Campylobacter jejuni Identifies a Bipartite Energy Taxis System Required for Motility" Molecular Microbiology, 40:214-224, 2001