Interactions between the Enteric Pathogen and the Host

Abstract

Bacteria have been associated with a wide variety of syndromes in animals and humans. These include enteropathies, urinary infections, meningitis and septicemia. Among the distinct set of tactics to prevail within the host, is the ability of bacteria to adhere to cellular targets. Adhesion to the gut by enteric bacteria occurs via several types of adhesins. During the last 15 years, much information has become available on bacterial adhesins and mechanisms governing bacteria-host interactions. Due to their location on the cell surface, establishing a carbohydrate frontier, and their inherent variability, glycosphingolipids and glycoproteins provide a wide range of binding sites for bacteria, toxins and more generally lectins. Bacterial lectins are localized either on the tip or along fimbrial filaments or on nonfimbrial structures. We examine in this short review, a collection of pathogen lectins, through their different receptor specificities. For sialic acid-binding lectins, the conformation of terminal sialic acid is essential for adhesion, whereas for other bacterial lectins, complementary sugars may be arranged in specific linear and/or branched sequences. Finally, it appears that the composition and structure of cell carbohydrates could in part explain the bacterial tropism and susceptibility or resistance of the host to enteric diseases.