Emergence of spontaneous bacterial peritonitis due to enterococci - risk factors and outcome in a 12-year...

Third-generation cephalosporins (TGC) constitute the empirical first-line therapy for spontaneous bacterial peritonitis (SBP). Hospitalisation, invasive procedures and use of antibiotics may challenge this concept due to an increase in enterococci and other TGC-resistant microorganisms.

To determine prevalence, risk factors and outcome of ascitic fluid infections caused by enterococci.

All independent episodes of culture-positive ascitic fluid between 2000 and 2011 in a German tertiary centre were analysed retrospectively.

Out of 244 positive ascitic fluid cultures, 90 episodes of monomicrobial SBP and 25 episodes of monomicrobial bacterascites (BA) in patients with decompensated cirrhosis were identified. Enterococcus spp. were isolated in 32 (28%) episodes. We noticed a profound increase in the frequency of enterococcal infection over the study period from 11% to 35% (P = 0.007). Univariate risk factors for enterococcal SBP/BA included nosocomial infection (OR = 4.56; 95% CI 1.90-10.97), previous use of antibiotics (OR = 5.63; 95% CI 1.81-17.49) and recent gastrointestinal endoscopy (OR = 3.17; 95% CI 1.33-7.54). Nosocomial infection (OR = 3.29; P = 0.011) and recent antibiotic therapy (OR = 3.88; P = 0.025) remained independent risk factors for enterococcal infection in multivariate logistic regression and these factors contributed also to the model when only SBP cases were considered. In subjects with monomicrobial SBP who were treated with TGC or ciprofloxacin, the probability of 90-day survival was 12% in enterococcal infection compared to 50% in non-enterococcal SBP (P = 0.022 in log-rank test).

Because of the increasing prevalence of enterococcal spontaneous bacterial peritonitis and its poor prognosis when treated inappropriately, clinicians should consider empirical therapy with anti-enterococcal antibiotics for patients with risk factors.