Prevalence of associated infections in community-acquired spontaneous bacterial peritonitis

The frequency with which other infections occur in association with spontaneous bacterial peritonitis is not known, but has implications for both pathogenesis and management. Spontaneous bacterial peritonitis that occurs in hospitalized patients is mainly a nosocomial infection, the study of which must take into account multiple confounding factors. We conducted a prospective study to compare the clinical features and the frequency of associated infections in patients with community-acquired spontaneous bacterial peritonitis to those of cirrhotic patients with ascites but without spontaneous bacterial peritonitis. Previous studies of spontaneous bacterial peritonitis have not found an infection consistently present at some other site, but those studies did not separate community-acquired from hospital-acquired spontaneous bacterial peritonitis.

Over a 5-yr study period, 176 cirrhotic patients with ascites were enrolled and were followed. There were 68 patients who had 83 admissions with spontaneous bacterial peritonitis and 108 patients with 124 admissions without spontaneous bacterial peritonitis. Of the 68 patients with spontaneous bacterial peritonitis, 56 had single episodes of peritonitis and 12 had 27 episodes of recurrent bacterial peritonitis. All episodes of spontaneous bacterial peritonitis were diagnosed within 24 h of admission. All subjects had cultures of ascitic fluid, blood, and urine.

Patients with spontaneous bacterial peritonitis were more often symptomatic than the nonspontaneous bacterial peritonitis patients. Ascites cultures were positive in 63 (76%) episodes of spontaneous bacterial peritonitis. The frequency of bacteremia in the spontaneous bacterial peritonitis group was significantly higher than that of the nonspontaneous bacterial peritonitis (56.6% vs. 4.8%, p < 0.0001). Bacteriuria occurred in 51 episodes of spontaneous bacterial peritonitis compared with only nine in nonspontaneous bacterial peritonitis patients (61.4% vs. 7.3%, p < 0.0001). Bacteriuria was observed even more often in recurrent bacterial peritonitis patients than in single episode bacterial peritonitis patients (77.8% vs. 53.6%, p < 0.0001). Most patients with bacteriuria had no urinary tract symptoms. There was no significant difference between the frequency of pneumonia in spontaneous bacterial peritonitis patients compared with nonspontaneous bacterial peritonitis patients (8.4% vs. 10.5%, p = 0.17).

Asymptomatic bacteriuria occurs often in association with community-acquired spontaneous bacterial peritonitis.