Spontaneous Bacterial Peritonitis among Cirrhotic Patients: Prevalence, Clinical Characteristics, and Outcomes

(1) Background: Spontaneous bacterial peritonitis (SBP) is a feared complication of liver cirrhosis. We investigated the prevalence of SBP, positive ascitic fluid cultures, and risk factors for mortality. (2) Methods: A retrospective analysis of all patients with cirrhosis hospitalized or in follow-up in a single center between 1996 and 2020. The clinical data, long-term complications, and mortality of SBP patients were compared with those of non-SBP patients. Ascitic fluid positive culture was compared with those without growth. (3) Results: We included 1035 cirrhotic patients, of which 173 (16.7%) developed SBP. Ascitic fluid culture growth was found in 47.4% of the SBP cases, with Escherichia coli bacteria detected in 38%, 24.4% grew ESBL-producing bacteria, and 14.5% displayed multidrug resistance. In a Cox regression model, SBP, male sex, prolonged INR at diagnosis, and hepatocellular carcinoma were found to be risk factors for mortality in cirrhotic patients. The long-term all-cause mortality was 60% in non-SBP and 90% in SBP patients. (4) Conclusions: Only a minority of cirrhotic patients developed SBP, 47.4% of which had positive ascitic fluid cultures with high antibiotic resistance. Growth of ESBL and multidrug resistant organisms is becoming more frequent in the clinical setting, reaching SBP mortality of 90%.