Abstract: In a first aspect, the present invention relates to a mutated Salmonella strain comprising mutations in flagellin II genes, like the fliF gene, in particular, in addition the aroA gene, the IpxR gene, the pagP gene, the pagL gene, the ydiV gene and optionally the eptA gene and further optionally, the arnT gene. In a further aspect, immunogenic compositions comprising said Salmonella strain are provided optionally together with a pharmaceutically accepted carrier, diluent or effluent. Moreover, a method for producing outer membrane vesicles of Salmonella is provided, said method comprises the steps of cultivating the Salmonella strain according to the present invention and isolating the outer membrane vesicles accordingly.

Abstract: In a first aspect, the present invention relates to a mutated Salmonella strain comprising mutations in flagellin II genes, like the fliF gene, in particular, in addition the aroA gene, the IpxR gene, the pagP gene, the pagL gene, the ydiV gene and optionally the eptA gene and further optionally, the arnT gene. In a further aspect, immunogenic compositions comprising said Salmonella strain are provided optionally together with a pharmaceutically accepted carrier, diluent or effluent. Moreover, a method for producing outer membrane vesicles of Salmonella is provided, said method comprises the steps of cultivating the Salmonella strain according to the present invention and isolating the outer membrane vesicles accordingly.