The goal of our research is to investigate the mechanism(s) of gut colonization by the diarrheic disease pathogen Clostridium difficile. C. difficileis the etiologic agent of C. difficile infection (CDI), a leading cause of nosocomial disease world-wide. CDI causes a spectrum of disease manifestations that range from mild diarrhea to lethal pseudomembranous colitis. Over 400,000 cases of CDI occur annually in the USA, imposing a $3.2 billion excess burden on the healthcare system. Research in our laboratory is focused on the molecular characterization of non-toxin virulence factors of C. difficile, and is aimed at designing interventions to combat as well as prevent CDI. We are also involved in multiple surveillance studies in Tucson-area hospitals that quantitate the incidence of both nosocomial and community-acquired CDI, via direct bacterial culture of patient samples as well as recovery of spores from abiotic environments such as hospital surfaces.