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Non-typhoidal <i>Salmonella</i> are a major cause of gastroenteritis worldwide, as well as causing bloodstream infections in sub-Saharan Africa with a high fatality rate. No vaccine is currently available for human use. Current vaccine development strategies are focused on capsular polysaccharides (CPS) present on the surface of non-typhoidal <i>Salmonella</i>. This study aimed to boost the amount of CPS purified from <i>S. Typhimurium</i> for immunization trials. Random mutagenesis with Tn<i>10</i> transposon increased the production of CPS colanic acid, by 10-fold compared to wildtype. Immunization with colanic acid or colanic acid conjugated to truncated glycoprotein D or inactivated diphtheria toxin did not induce a protective immune response in mice. However, immunization with Generalized Modules for Membrane Antigens (GMMAs) isolated from colanic acid overproducing isolates reduced <i>Salmonella</i> colonization in mice. Our results support the development of a GMMA-CPS-based vaccine against non-typhoidal <i>Salmonella</i>.