A Mouse Model of Persistent Salmonella Infection (13-Nov-2004)

Introduction When a pathogenic microorganism first infects its host there is usually a dramatic engagement with the innate and adaptive immune systems that may result in disease symptoms. If the microbe and the host survive this initial interaction, the adaptive host immune system usually clears the invading offender. However, some pathogenic bacteria are capable of maintaining infections in mammalian hosts even in the presence of inflammation, specific antimicrobial mechanisms, and a robust adaptive immune response, which will serve as our definition of a persistent infection. For example, Salmonella typhi causes systemic infection (typhoid fever) that involves colonization of the reticuloendothelial system (RES). Some S. typhi infected individuals become life-long carriers, periodically shedding high numbers of bacteria in their stools. Persistently infected carriers serve as the reservoir of these pathogens and the carrier state is an essential feature for survival within a restricted host population.