ORAL ENTEROPATHOGENIC E. coli (EPEC) INFECTION of NEWBORN MICE

Enteropathogenic E. coli (EPEC) represent a major causative agent of infant diarrhea associated with significant morbidity and mortality in developing countries. Although studied extensively in vitro, the investigation of the host-pathogen interaction in vivo has been hampered by the lack of a suitable small animal model. Here, we orally infected newborn mice with EPEC and observed a spontaneous intestinal colonization restricted to the postnatal period. Intimate attachment of the bacteria to the epithelial plasma membrane and microcolony formation were observed by immunofluorescence and occurred in a type III secretion system (TTSS) dependent manner. Similarly, EPEC-induced innate immune stimulation required an intact TTSS and led to the upregulation of a restricted set of enterocyte response genes. Together, we present the first suitable small animal model to study the pathogenesis of EPEC.