A 56-year-old patient with advanced liver failure due to alcoholic cirrhosis is brought to the ED complaining of new onset fever and abdominal pain and confusion since yesterday. On physical exam the abdomen is severely distended. A therapeutic tap is carried out, 6 liters of fluid is drained, and samples are sent. The ascitic fluid shows 500 neutrophils/mm3 without sign of secondary source of infection. All the following are reasonable steps in ED management of this patient EXCEPT: