Changing pattern of microorganisms and antibiotic resistance rate of spontaneous bacterial peritonitis: A 12-year experience

Joo, Moon Kyung; Yeon, Jong Eun; Lee, Sun Jae; Suh, Sang Jun; Jung, Young Kul; Kim, Jeong Han; Kim, Ji Hoon; Yim, Hyung Joon; Byun, Kwan Soo

Abstract

BACKGROUND/AIMS: Recently, the prognosis for spontaneous bacterial peritonitis (SBP) has improved; however, the causative microorganisms and antibiotic resistance rates are changing. We evaluated the changing pattern of causative agents and antibiotic resistance rates of SBP over a 12-year period.
METHODS
We retrospectively analyzed 113 patients who were diagnosed with SBP and in whom ascites cultures were positive between 1996 and 2007. The 12-year period was subdivided into 6-year terms (period A, 1996~2001; and period B, 2002~2007).
RESULTS
One hundred thirteen of 410 cases of SPB had positive ascites cultures. Thirty-seven cases were from period A and 76 cases were from period B. Hospital-acquired SBP was more common during period B. Gram negative microorganisms were isolated from 78% of SBP cases, and the most common microorganism was E.coli (60%). The resistance rates for ampicillin and ciprofloxacin were similar between the two periods, but resistance to cefotaxime was more frequent in period B (3% vs. 26%, p=0.002), and ESBL-producing E.coli was only cultured in period B (0% vs. 32%, p=0.002). Most of the initial antibiotics used were cefotaxime; carbapenem was used as a secondary antibiotic only in period B (0% vs. 55%, p=0.007). ESBL-producing microorganisms were the only predictor of in-hospital mortality based multivariate analysis (OR: 4.14, 95% CI: 1.09-15.07, p=0.037).
CONCLUSIONS
No change in pattern of microorganisms in the ascites of patients with SBP was noted during the 12-year period under study, but there was a significant increase in the incidence of hospital-acquired SBP, resistance to cefotaxime, and ESBL-producing E.coli when comparing the outcomes of periods A and B. ESBL-producing microorganisms were the only predictor of in-hospital mortality.