Epidemiology of Spontaneous Bacterial Peritonitis, Bacterial Species and Resistances

Abstract

Purpose: Current guidelines for treatment of spontaneous bacterial peritonitis (SBP) recommend third-generation cephalosporins as first-line therapy. However, these guidelines do not reflect recent published literature on regional differences in infective patterns or changes in antibiotic resistance patterns. Therefore, we hypothesize that the wide-spread usage of third generation cephalosporins as first-line therapy for SBP has led to an increase in resistance among SBP organisms and that antibiotic prophylaxis has led to a shift in the pattern of organisms that cause SBP. Methods: Adult patients diagnosed with SBP from January 2005 through December 2015 in the BIDMC were identified with ICD-9 or ICD-10 codes and documented peritoneal fluid results. Initial antibiotic was defined as the first antibiotic treatment regimen used for documented infections. Patient demographics, clinical characteristics, and reported mortality during hospitalization and at 30 and 90 days were analyzed to build a conditional logistic regression model. Culture-positive data underwent a separate sub-analysis to determine the bacterial epidemiology and antibiotic resistance patterns. Results: During the study period, 160 cases were reported, with third-generation cephalosporins being the initial antibiotic for 65% of cases. The most common causative organism of culture-positive SBPs was Escherichia coli, making up 37.5% of culture-positive episodes. Less common organisms included streptococcus (23.2%), enterococcus (10.7%), klebsiella (8.9%), and staphylococcus (8.9%) species. Only 57% of organisms were sensitive to third-generation cephalosporins. Patients with higher MELD scores, with encephalopathy, on antibiotic prophylaxis, and who developed SBP while in-hospital were more likely to fail first-line therapy. Conclusions: Our results indicate that there is significant resistance against third-generation cephalosporins in the bacterial population that causes SBP at BIDMC. Therefore, additional research must be conducted in order to develop new guidelines to treat the changing bacteria population.