Deletion of a prophage-like element causes attenuation of Salmonella enterica serovar Enteritidis and promotes protective immunity

Abstract

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a wide host range serovar belonging to the S. enterica genus. Worldwide, it is one of the most frequent causes of food borne disease. Similar to S. Typhimurium, some virulence genes of S. Enteritidis are located in pathogenicity islands and prophages. In this study we have generated a mutant strain of S. Enteritidis lacking a prophage-like element, denominated φSE12. The resulting mutant strain was attenuated and promoted protective immunity in infected mice. Although S. Enteritidis strains lacking the complete prophage φSE12 remained capable of surviving inside phagocytic cells, they showed a significantly reduced capacity to colonize internal organs and failed to cause lethal disease in mice. Consistent with these data, infection with S. Enteritidis strains lacking prophage φSE12 promoted the production of anti-. Salmonella IgG antibodies and led to protection against a challenge with virulent strains of S. Enteritidis. Thes