Treatment of Spontaneous Bacterial Peritonitis

Spontaneous bacterial peritonitis (SBP) is an infection of patients with cirrhosis and ascites. This peculiarity is due to the frequent intestinal translocation that allows bacteria to cross the intestinal barrier, colonizing the ascitic fluid. In cirrhosis, SBP is inferior only to urinary tract infections. It is prevalently sustained by Gram-negative bacteria such as Escherichia coli and Klebsiella. Risk factors for developing SBP are advanced age, refractory ascites, variceal bleeding, renal failure, low albumin levels (below 2.5 g/ml), bilirubin over 4 mg/dl, Child-Pugh class C and a previous diagnosis of SBP. Thus, this is an indication for a long-term antibiotic prophylaxis with norfloxacin. Renal failure - especially the hepatorenal syndrome - complicates SBP in about 20% of cases independently of the efficacy of the antibiotic therapy. The mortality of these patients is about 90%. Infusion of albumin significantly reduces the incidence of hepatorenal syndrome and consequently the risk of death. Long-term quinolonic prophylaxis as well as increased antibiotic therapies are causing the emergence of multidrug-resistant agents as frequent causes of SBP. In such cases, the antibiotic sensitivity to quinolones is low, and European recommendations suggest a second-line antibiotic therapy, including meropenem or piperacillin plus tazobactam. Collection of blood, urine and ascitic fluid for cultures is important for bacterial recognition, possibly before starting an empirical antibiotic therapy. Indeed, the probability of positive cultures rapidly vanishes when they are performed during already implemented antibiotic administration. It is important to know that a failure of the first-line therapy is associated with an increased probability of death.