Vincent B. Young-Research Summary

Our group is interested in the role bacteria play in acute and chronic gastrointestinal (GI) illness. To this end, we study the role of what would traditionally be considered “pathogenic bacteria” in gastrointestinal illness. In addition, we also examine how the population structure of the indigenous GI microbiota can influence the host-pathogen interaction and how changes in the community structure of the indigenous microbiota itself can lead to pathogenic states. Specific areas of investigation include:

MURINE MODELS OF INFLAMMATORY BOWEL DISEASE

The bacterium Helicobacter hepaticus have been implicated as a trigger of inflammatory bowel disease (IBD) in immune-altered mice. We have been investigating how H. hepaticus can circumvent normal protective immune responses and in turn how this leads to the development of IBD in immune-altered mice.

GASTROINTESTINAL MICROBIAL ECOLOGY

The bacterial community of the gut is part of a complex ecosystem. A significant proportion of the members of these bacteria have not been cultured to date in the laboratory, preventing understanding of the complete diversity of this ecosystem. The advent of culture-independent methods to examine the ecology of this community has provided insight into the role it plays in various disease processes. We have investigated the role the gut microbial community plays in the development of antibiotic-associated diarrhea in humans. We are also defining the changes in the GI microbiota related to H. hepaticus-induced IBD and determining if probiotic organisms exert their beneficial effect via changes in the gut microbiota.

SELECTED PUBLICATIONS

Young, V.B., Knox, K.A. and Schauer, D.B. (2000) Cytolethal distending toxin sequence and activity in the enterohepatic pathogen H. hepaticus. Infect. Immun. 68:184-191.

Young, V.B., Knox, K.A., Pratt, J.S., Cortez, J.S., Mansfield, L.S., Rogers, A.B., Fox, J.G., and Schauer, D.B., (2004) In vitro and in vivo characterization of Helicobacter hepaticus cytolethal distending toxin mutants. Infect. Immun. 72:2521-2527.

Young, V.B., and Schmidt, T.M. (2004) Antibiotic-associated diarrhea accompanied by large-scale alterations in the composition of the fecal microbiota. J. Clin. Microbiol. 42:1203-1206.

Kuehl, C.J., Wood, H.D., Marsh, T.L., Schmidt, T.M. and Young, V.B., (2005) Colonization of the cecal mucosa by Helicobacter hepaticus impacts the diversity of the indigenous microbiota. Infect. Immun. 73:6952-6961.

Pratt, J.S., Sachen, K.L., Wood, H.D., Eaton, K.A. and Young, V.B., (2006) Modulation of host immune responses by the cytolethal distending toxin of Helicobacter hepaticus. Infect. Immun. 74:4496-4504.

Chang JY, Antonopoulos DA, Kalra A, Tonelli A, Khalife WT, Schmidt TM, Young VB. Decreased diversity of the fecal microbiome in recurrent Clostridium difficile-associated diarrhea. J Infect Dis 197 (3): 435-438, 2008.