Optimization of ascitic fluid culture in spontaneous bacterial peritonitis

Introduction and aims

Spontaneous bacterial peritonitis (SBP) is ascitic fluid (AF) infection in the absence of an intraperitoneal source of infection in patients with liver disease and portal hypertension. The aim of this study was to evaluate the yield of microbiological cultures to optimize their collection and systematic implementation in routine clinical practice.

Methods

We analyzed two cohorts: the first consisted of retrospective data from the clinical records of 156 consecutive episodes of SBP from January 2003 to December 2005 (group R), and the second was composed of data collected prospectively from October 2007 to October 2008, consisting of 79 episodes (group P), with systematic inoculation of 10 cc of AF in each blood culture bottle.

Results

No significant differences were demonstrated in baseline epidemiological or clinical characteristics among episodes, except the more frequent presence of alcoholic liver disease and the incidence of tense ascites, paralytic ileus and kidney failure at diagnosis in group P. Microbiological isolation in AF was achieved in 12.2% of the episodes in group R compared with 53.2% in group P (p = 0.001) and 8.5 and 26.6% (p = 0.001) in blood culture, respectively. Microbiological isolation was achieved in 65.8% of episodes in group P versus 19.2% in group R (OR 8; 95% CI: 4.4-14.9; p = 0.001). The most frequently isolated organism in AF in group P was Escherichia coli (42.9%).

Conclusions

Optimizing the diagnostic procedure in cirrhotic patients with ascites significantly increases diagnostic microbiologic performance.