Leung J W, Liu Y L, Leung P S, Chan R C, Inciardi J F, Cheng A F
Division of Gastroenterology and Mr. and Mrs. C. W. Law Biofilm Research Center, University of California Davis, Sacramento, California 95817, USA.
Gastrointest Endosc. 2001 Sep;54(3):346-50. doi: 10.1067/mge.2001.117546.
Bacterial beta-glucuronidase causes deconjugation of bilirubin diglucuronide resulting in the precipitation of calcium bilirubinate, which contributes to biliary sludge and stone formation. This process is attributed to enzyme activity produced by the aerobic enterobacteriaceae such as Escherichia coli and Klebsiella sp. The presence of Clostridium sp. was detected in 48 of 56 intrahepatic stones by using polymerase chain reaction techniques and cultured Clostridium perfringens from 14 of 18 unblocked biliary stents. Such bacteria are reported to produce beta-glucuronidase activity. The aim of this study was to determine the proportion of biliary bacteria isolated from pigment stones and stents that produce beta-glucuronidase and to compare the enzyme activity expressed by the different bacteria in human bile.
A total of 202 bacteria were isolated from blocked and unblocked biliary stents and pigment ductal stones recovered from patients. Of these, 61 bacteria expressed beta-glucuronidase activity in brain heart infusion broth. These 61 bacteria were subsequently grown in human bile under aerobic or anaerobic conditions to the early stationary phase and assayed for beta-glucuronidase activity by using rho-nitrophenyl beta-D glucuronide as substrate. Results were normalized and reported as units of enzyme activity per milligram protein of the bacteria.
C. perfringens produced beta-glucuronidase enzyme activity that was 34-fold higher than that for E coli, Staphylococcus, Corynebacterium sp., Bacillus sp., Enterococcus sp., Acinetobacter sp., Streptococcus sp., and Klebsiella sp.
C. perfringens with its higher enzyme activity is more important in the deconjugation of bilirubin diglucuronide than E coli and Klebsiella sp.
细菌β-葡萄糖醛酸酶可使胆红素二葡萄糖醛酸酯去结合，导致胆红素钙沉淀，这会促使胆泥和结石形成。此过程归因于需氧肠杆菌科细菌（如大肠杆菌和克雷伯菌属）产生的酶活性。通过聚合酶链反应技术在56颗肝内结石中的48颗检测到梭菌属的存在，并从18个未阻塞的胆管支架中的14个培养出产气荚膜梭菌。据报道，此类细菌可产生β-葡萄糖醛酸酶活性。本研究的目的是确定从色素结石和支架中分离出的产生β-葡萄糖醛酸酶的胆道细菌比例，并比较不同细菌在人胆汁中表达的酶活性。
从患者体内回收的阻塞和未阻塞胆管支架及色素性胆管结石中总共分离出202株细菌。其中，61株细菌在脑心浸液肉汤中表达β-葡萄糖醛酸酶活性。随后，将这61株细菌在需氧或厌氧条件下于人胆汁中培养至早稳定期，并以ρ-硝基苯基β-D葡萄糖醛酸苷为底物检测β-葡萄糖醛酸酶活性。结果进行标准化处理，并报告为每毫克细菌蛋白的酶活性单位。
产气荚膜梭菌产生的β-葡萄糖醛酸酶活性比大肠杆菌、葡萄球菌、棒状杆菌属、芽孢杆菌属、肠球菌属、不动杆菌属、链球菌属和克雷伯菌属高34倍。
产气荚膜梭菌因其较高的酶活性，在胆红素二葡萄糖醛酸酯的去结合过程中比大肠杆菌和克雷伯菌属更重要。
