Vibrio vulnificus detected in the spleen leads to fatal outcome in a mouse oral infection model.

Vibrio vulnificus causes rapid disseminating septicemia by oral infection in infected individuals who have an underlying disease, especially chronic liver diseases. Although the elucidation of specific risk factors for V. vulnificus infection in patients with liver diseases is of urgent importance, no appropriate experimental animal model that mimics the liver diseases in this bacterial infection has been available so far. To discover these risk factors, we generated a liver disordered mouse by performing bile duct ligation (BDL). Hepatitis developed in the BDL mice; however, this did not affect mortality in mice after orogastric administration of V. vulnificus, suggesting that the liver disorders caused by the BDL were not risk factors for V. vulnificus septicemia. When the dead and surviving mice were compared, V. vulnificus could be detected from the spleen only in the dead group. Furthermore, significantly higher numbers of V. vulnificus were detected from the intestines in the dead group than in the surviving group ( P < 0.001). These findings suggested that proliferation of the challenge inoculum in the intestine was needed for the oral infection with V. vulnificus, and that the elimination of V. vulnificus in the liver and/or spleen plays a critical role in survival of the host.