Publication Date

Spring 2014


School of Health Sciences


Biochemistry and Molecular Biology


intestinal microbiota, Citrobacter rodentium, colonization, streptomycin-treated mouse model


Bacterial Infections and Mycoses


The human intestine hosts a diverse community of bacteria known as the intestinal microbiota. The intestinal microbiota have a symbiotic relationship with the host organism. Current research does not clearly define the effect these commensal microorganisms have on the overall maintenance of gastrointestinal health, including protection from the invasion and pathogenesis of foreign bacteria known as pathogens. EHEC O157:H7 causes severe sickness and can be life-threatening, but is difficult to study in vivo. One challenge is that EHEC does not colonize the preferred animal model for human GI studies: the murine intestine. However, the murine pathogen Citrobacter rodentium has been shown to colonize the mouse intestine and is used in current research as a model for EHEC colonization and infection. However, no one knows how the intestinal microbiota respond during the colonization C. rodentium and is addressed in this thesis. The colonization of a streptomycin-resistant strain of C. rodentium was observed over a 15-day period and quantified in both conventional and streptomycin-treated mouse models using genus-specific primers and quantitative PCR. The day 7 results indicate that there is a significant increase of Bacteroidales in the uncolonized, streptomycin-treated model, which is consistent with previous studies. The characterization of the intestinal microbiota has yet to be fully described for the colonization of C. rodentium in the mouse intestine as data analysis for this study continues. The anticipated outcomes may lead to the prevention and clinical care of EHEC on a global scale.