SALMONELLOSIS, INCLUDING TYPHOID-FEVER

Salmonella spp. are a major cause of human morbidity and mortality. Th e increased frequency of egg-associated Salmonella enteritidis outbrea ks emphasizes the need for new prevention and control strategies. With the emergence of multidrug-resistant Salmonella strains, third-genera tion cephalosporins and quinolones are increasingly necessary to treat both complicated non-typhoidal Salmonella infections and typhoid feve r. However, resistance is now being reported to both classes of antimi crobial agents, and there is unresolved concern about the use of quino lones in children aged less than 10 years. Recent studies of Salmonell a pathogenesis and interactions with epithelial cells and macrophages have increased our understanding of Salmonella spp. infection. Interes t also has been generated by the development of virulence-attenuated S almonella typhi strains as new oral vaccines and as multivalent-vaccin e vectors to express heterologous antigens to protect against a variet y of infectious diseases.