Abstracts
1999 Digestive Disease Week

# 2074 THE CHOLANGIOVENOUS REFLUX OF BILIARY BACTERIA: E. COLI REFLUX MORE READILY THAN PSEUDOMONAS AND ARE MORE COMMONLY ASSOCIATED WITH BACTEREMIA
Lygia Stewart, Univ of CA, San Francisco and VA Med Ctr, San Francisco, CA; A L Oesterie, G A Kan, J McL Griffiss, L W Way, Univ of CA, San Francisco, San Francisco, CA

We have previously reported that E. coli and Pseudomonas behave differently when in the biliary tree. In an analysis of a large cohort of patients with gallstone disease where bacteria were categorized according to the magnitude of the clinical illness they caused, we noted that E. coli generally (63%) caused a serious illness (bacteremia, hypotension, organ dysfunction, cholangitis, abscess) while Pseudomonas most often (64%) caused no clinical infection. These differences persisted even in the subgroup with bacteria in the CBD: E. coli caused severe illness in 90% of cases and was cultured from blood in 37%, while Pseudomonas caused severe illness only 38% of cases and was never cultured from the blood. Because of these differences, the cholangiovenous reflux of E. coli and Pseudomonas was studied in rats.
Methods: Five E. coli and three Pseudomonas biliary strains were studied, with 4-11 rats for each bacterial strain. 107 bacteria in log phase growth were injected retrograde into the CBD at 30 cm H2O and SVC blood was obtained for culture at 1, 2.5, 5, 10, and 15 minutes.
Results: Results are shown in the graph. E. coli (solid lines, circle) refluxed more readily and persisted in the systemic circulation longer than Pseudomonas (dashed lines, X). Differences were highly significant (p<0.001, t-test, 2.5-15 min values). At 15 minutes, an average of 2.7 X104 E. coli CFU/ml compared with 30 Pseudomonas CFU/ml were present in the blood. Conclusions: E. coli was more able than Pseudomonas to gain access to the systemic circulation when present under 30 cm H2O pressure in the bile duct. While it is known that E. coli is the most common pathogen causing cholangitis, these unique species differences have not previously been reported.

Copyright 1996 - 1999, SSAT, Inc.