Intestinal decontamination with rifaximin may prevent the formation of a first episode of spontaneous bacterial peritonitis (SBP) for cirrhotic patients with large ascites. Because this new finding comes from a retrospective analysis, prospective randomized trials are required. Nevertheless, for patients with multiple drug allergies (penicillins, quinolones, sulfa) who may benefit from rifaximin for other reasons (ie. hepatic encephalpathy), there is reason to be excited about its use as SBP prophylaxis.
For more: http://www.ncbi.nlm.nih.gov/pubmed/22878533