Abstracts
1999 Digestive Disease Week

# 3478 GALLSTONE PATHOGENESIS: SLIME PRODUCTION BY BILIARY BACTERIA IS MORE IMPORTANT THAN BETA-GLUCURONIDASE PRODUCTION
Lygia Stewart, Univ of CA, San Francisco and VA Med Ctr, San Francisco, CA; R Pontz, A L Oesterle, J McL Griffiss, L W Way, Univ of CA, San Francisco, San Francisco, CA

Pigment stones are felt to form as a result of deconjugation of bilirubin by bacterial b-glucuronidase, resulting in precipitation of Cabilirubinate that is then aggregated into stones with an anionic glycoprotein. Slime or glycocalyx (an anionic glycoprotein) is produced by bacteria causing foreign body infections and has been implicated in the blockage of biliary stents. We previously demonstrated bacteria within pigment portions of gallstones, and postulated a bacterial role in pigment stone formation through b-glucuronidase or slime production. Since we found only 40% of biliary bacteria produced b-glucuronidase, we examined slime production. Methods: 91 biliary bacterial isolates from 61 patients, and 10 control stool isolates, were quantitatively tested for slime production by measuring optical density (OD). Results: Results for each species are shown in the graph. Average slime production (OD) by biliary bacteria was 42 versus 2.9 for stool bacteria (p < 0.001). Overall, 77% of biliary bacteria produced slime (OD>3) versus 10% of stool isolates. 82% of all patients, 90% of patients with CBD stones, 93% of patients with biliary tubes, and 100% of patients with 1o CBD stones had one or more bacteria that produced slime. Comparatively, only 42% of all patients, 60% of patients with CBD stones, and 62% of patients with 1o CBD stones had bacteria that produced b-glucuronidase. Conclusions: Most biliary bacteria produced slime, and slime production correlated better than b-glucuronidase production did with stone formation. Patients with 1o CBD stones and biliary tubes had the highest incidence of slime production, suggesting that bacterial slime is important gallstone formation and the blockage of biliary tubes.

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