Dr. Bäumler studies the molecular mechanisms of Salmonella interaction with the intestinal mucosa. The genus Salmonella contains a group of closely related organisms that are pathogenic for humans and other vertebrates. The human disease manifestations caused most frequently by Salmonella serotypes worldwide are typhoid fever, gastroenteritis and bacteremia. One focus of his research is to understand how Salmonella typhi, the causative agent of typhoid fever, can overcome mucosal barrier functions and disseminate within its human host while infections with non-typhoidal Salmonella serotypes (e.g. S. typhimurium) manifest as a localized gastroenteritis in immunocompetent individuals. Mucosal barrier functions that prevent spread of S. typhimurium beyond the intestine and mesenteric lymph node are also under study, because an impairment of these defenses in immunocompromised individuals (e.g. HIV patients) can lead to a life threatening bacteremia, which is currently a leading cause of adult’s hospital admissions in Sub-Saharan Africa. Finally, he is interested in understanding how S. Typhimurium benefits from intestinal inflammation and successfully competes with the gut microbiota for attachment sites and nutrients in the intestine to promote its transmission by the fecal oral route. He is studying the molecular mechanisms underlying the pathogenesis of typhoid fever, gastroenteritis and bacteremia using a variety of animal models in combination with bacterial genetics and tissue culture models.