Abstract: The invention provides methods of screening for modulators of microbial PA-I lectin/adhesin activity, including modulators of PA-I expression, as well as the modulators so identified, pharmaceutical compositions and kits containing such modulators. These modulators include soluble and membrane-bound bacterial signaling compounds produced by cells of a host containing a microbial pathogen. Methods for preventing and treating cell disorders, such as epithelial cell disorders including gut-derived sepsis, a burn injury, neonatal necrotizing enterocolitis, severe neutropenia, toxic colitis, inflammatory bowel disease, enteropathy, transplant rejection, pouchitis, pig belly, Pseudomonas-mediated opthalmologic infection, Pseudomonas-mediated otologic infection and Pseudomonas-mediated cutaneous infection, using the modulators are contemplated, as are methods for ameliorating a symptom associated with such a disorder.