Elsevier

Gastrointestinal Endoscopy

Volume 52, Issue 6, December 2000, Pages 725-729
Gastrointestinal Endoscopy

Original Articles
Early attachment of anaerobic bacteria may play an important role in biliary stent blockage,☆☆,

Presented in part at DDW, Orlando, Florida, May 1999.
https://doi.org/10.1067/mge.2000.108964Get rights and content

Abstract

Background: In vitro studies have demonstrated that ciprofloxacin suppresses Escherichia coli attachment on stents, and ciprofloxacin has been shown to prolong stent patency in cats. However, clinical studies with antibiotic prophylaxis have produced conflicting results. The aim of this study was to isolate and identify the bacteria that attach early on unblocked stents removed from patients and to study their enzyme activities. Methods: Eighteen unblocked biliary stents were removed from 17 patients (benign obstruction in 14 and malignant obstruction in 4). All patients received antibiotic prophylaxis (mean of 6 days). Stents were in place for a mean of 33 days. The inside of stents was scraped and sludge was cultured aerobically and anaerobically. Identification of isolated bacteria and measurement of β-glucuronidase and phospholipase C activities were performed by using standard techniques. Gastric and duodenal juice from 18 patients with no biliary diseases was used as control samples. Results: All stents were patent and only 6 had visible sludge. There were 19 anaerobes isolated from 16 stents (Clostridium perfringens 13, Clostridium bifermentans 4 and Bacteroides fragilis 2). Phospholipase C was detected in all Clostridium species. β-Glucuronidase was produced only by 12 of 13 C perfringens isolates. Sixteen aerobes including Enterococcus species and Bacillus species were isolated but none produced β-glucuronidase or phospholipase C. There were no aerobic gram-negative bacteria isolated from stents. Clostridium species and B fragilis were not recovered from the control samples. Conclusions: In patients who had received antibiotic prophylaxis against gram-negative bacterial infection, anaerobic bacteria may play a role in initiating stent blockage. (Gastrointest Endosc 2000;52:725-9.)

Section snippets

Stents

Eighteen biliary stents were removed from 17 patients who had undergone endoscopic stent insertion between January and October 1998. The mean age of the patients was 50 years and the ratio of men to women was 1.3:1. The indications for biliary stent insertion are given in Table 1.

. Indications for biliary stent placement

Benign causes14
 Bile leak8
 Pancreatitis2
 Papillary stenosis1
 Bile duct stone2
 Primary sclerosing cholangitis1
Malignant causes4
 Gallbladder cancer1
 Pancreatic cancer3
The mean length of

Results

All stents were patent with only 6 of 18 stents containing small deposits of sludge. Sixteen aerobic bacteria were isolated, viz, Enterococcus sp 8, Bacillus sp 3, Staphylococcus sp 2, Aspergillus sp 2 and Candida sp 1, but there were no E coli or Klebsiella sp identified among the recovered bacteria (Table 2).

. Spectrum of bacteria isolated from unblocked stents

Aerobic bacteria16
 Gram-positive bacteria16
  Enterococcus8
  Bacillus3
  Staphylococcus2
  Aspergillus2
  Candida1
 Gram-negative bacteria0
Anaerobic

Discussion

Bacterial infection plays a significant role in the biliary sludge formation that predisposes to stent blockage. Different bacteria have been isolated from biliary sludge, the most common being the gram-negative E coli and Klebsiella sp and the gram-positive Enterococcus sp.10, 18 However in this study, E coli and the other gram-negative enteric bacteria were absent in the unblocked stents. All of the 18 patients had received a short course of antibiotic(s) immediately before or after stent

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    J.W.L. is supported by VA Merit Review Grant #94-07-003.

    ☆☆

    Reprint requests: Joseph Leung, MD, Division of Gastroenterology, PSSB, Ste 3500, 4150 V St., UC Davis Medical Center, Sacramento, CA 95817.

    Gastrointest Endosc 2000;52:725-9

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