A 58 year old man living in the Midwest presents to the Emergency Department with fatigue, diffuse abdominal pain and distension, loose stools, and fever.  The patient has a history of alcoholic cirrhosis and is employed as a small animal veterinarian.  His only reported travel is a recent vacation to New Orleans, where he consumed mostly oysters and seafood.

Ascites fluid was collected and submitted to the laboratory; it was cloudy with a markedly elevated leukocyte count, with a neutrophilic predominance.

Blood cultures were collected and submitted to the laboratory, along with the ascites fluid.  After overnight incubation, the blood cultures signaled positive and the ascites fluid exhibited abundant growth on blood, chocolate and MaConkey agar.  The isolate was oxidase and indole positive.  The same organism was recovered from the blood cultures.

What is the most likely identity of the organism causing this man's infection?