Antimicrobial therapy and prevention of spontaneous bacterial peritonitis.

Spontaneous bacterial peritonitis is a frequent and serious infection in cirrhotic patients with ascites. A high index of suspicion is required for early diagnosis and rapid institution of treatment. The common micro-organisms involved in SBP are the aerobic Gram-negative bacilli and Gram-positive cocci that inhabit the intestine. Empiric antibiotic therapy active against these organisms should be instituted as soon as possible to improve survival. Third generation cephalosporins are very effective and safe as the initial empiric antibiotic regimen. Alternatives include beta-lactam-clavulanic acid combinations and other broad-spectrum antibiotics, although cost benefit considerations are important in selection. If cultures and susceptibility tests allow, antibiotic therapy should be altered to provide optimum narrow-spectrum and cost-effective treatment. Recent evidence suggests that (at least in the case of cefotaxime), 5-day treatment is equally effective as 10-day treatment. Except in patients awaiting liver transplantation, antibiotic prophylaxis of SBP is not recommended at present, as the few trials performed have not been able to demonstrate superior results for survival, hospital admissions or cost-effectiveness, over prompt diagnosis and therapy of individual episodes of SBP.