Abstract: Methods for identifying molecules which inhibit the virulence or pathogenicity of Helicobacter pylori by modulating the activity of hydrolases encoded by genes amiA, mltD and slt. Compositions and diagnostic and treatment methods using hydrolases and molecules which inhibit them.

Abstract: A method for identifying a compound that modulates the interaction between Nod1 and a Gram-negative bacteria comprising contacting a Nod1 expressing cell with a cagPAI-positive H. pylori in the presence of a compound, contacting a Nod1 expressing cell with a cagPAI-positive H. pylori in the absence of said compound, and detecting the activation of a pro-inflammatory factor and/or the production of a pro-inflammatory cytokine or chemokine, wherein altered activation and/or production indicates that said compound modulates the interaction between Nod1 and the Gram-negative bacteria. The method is useful for identifying compounds for regulating the signaling cascade involving Nod1 against Gram-negative bacteria that cause mucosal inflammation in animal hosts.