Clinical significance of spontaneous Aeromonas bacterial peritonitis in cirrhotic patients: a matched case-control study

Abstract

Background: Although Aeromonas species are known to cause bacteremia in patients with cirrhosis, less is known about spontaneous bacterial peritonitis (SBP) caused by Aeromonas species in these patients.

Methods: We performed a retrospective, matched case-control study (1:2 ratio) consisting of patients presenting with SBP due to Aeromonas species from January 1997 through December 2006. Control subjects were patients with SBP caused by other organisms and were matched to the patients by age (+/- 1 year) and sex.

Results: We identified 43 patients with SBP due to Aeromonas species, 40 (93%) of whom had Aeromonas hydrophila infection and 3 (7%) of whom had Aeromonas sorbia infection. There were 81 control subjects, of whom 38 (47%) were infected with Escherichia coli, 25 (31%) were infected with Klebsiella species, 12 (15%) were infected with Streptococcus species, and 6 (7%) were infected with other bacteria. Baseline Child-Pugh class and model for end-stage liver disease score did not differ between groups. A significant increase in the incidence of infection during the warm season (July-September) was observed in the group with SBP due to Aeromonas species, compared with the group with SBP due to other bacteria (63% vs. 25%; P < .001). Diarrheal episodes were significantly more frequent in the group with SBP due to Aeromonas species (26% vs. 6%; P = .002). There were no statistically significant differences between groups with regard to appropriateness of initial antibiotic therapy,3-day mortality, and 30-day cumulative survival. In the group with Aeromonas infection, the in-hospital mortality rate was 23%; septic shock was the only independent prognostic factor of in-hospital mortality (odds ratio, 34.5;95% confidence interval, 1.9-640.6; P = .02).

Conclusion: Aeromonas species should be considered to be a causative organism of SBP in cirrhotic patients presenting with diarrheal episodes during the warm season. Compared with SBP caused by other organisms, SBP due to Aeromonas species was not associated with more-advanced cirrhosis.