Identification of in vivo-induced genes during infection of chickens with Salmonella enterica serovar Enteritidis

•We used in vivo-induced antigen technology with Salmonella Enteritidis in chickens.•We identified 42 genes expressed in vivo.•Genes expressed in vivo covered metabolism, transport, regulation and virulence.•The expression of selected genes was confirmed by qRT-PCR.

Chickens are an important source of food worldwide and are often infected with food-poisoning serovars of Salmonella enterica, frequently Salmonella Enteritidis (SE), without exhibiting clinical signs of disease. Ivi (in vivo induced) genes identified using in vivo-induced antigen technology (IVIAT) are expressed only during bacterial infection and have the potential value of identifying epidemic strains and antigens which can form the basis for sub-unit vaccine development. We applied IVIAT to SE strain 50041 and identified 42 ivi genes. Eight representative ivi genes were further confirmed by qRT-PCR as being expressed only in vivo within 48 h of infection compared with that of in vitro-cultured. Although our results indicated that the identified ivi genes are expressed only in vivo, further research is needed to elucidate the exact roles of these genes during infection and pathogenesis.