Structure, function, and assembly of adhesive organelles by uropathogenic bacteria

Bacteria assemble a variety of adhesive proteins (adhesins) on their surface to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. Adhesins recognize specific receptors expressed by specific subsets of host cells. Therefore, the repertoire of adhesins expressed by a pathogen play a major role in dictating the tropism of the pathogen toward specific host tissues and organs. Moreover, binding of bacterial adhesins to host cell receptors influences subsequent events by triggering signaling pathways in both the host and bacterial cells. These signaling pathways may determine whether the bacteria remain extracellular or become internalized, and influence the intracellular trafficking of invaded bacteria and their ability to survive and replicate (1, 2). The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities, including biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites that include the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens.