New Research Examines Bacterial Colonies that Form in Bile Duct Stents

Scientists in Germany have discovered which bacteria colonize and form biofilms in the stents that are put in to clear bile ducts blocked as a result of cancer.

Researchers at the Helmholtz-Centre for Infection Research (HZI) discovered “specific bacterial species as main colonizers” of the stents. In addition, they found that Streptococcus anginosus was a “recurrent, dominant” colonizer.

When the bacteria form biofilms in the stents, the researchers explained, they become protected from the body’s normal immune response as well as antibiotics. The German team then set out to analyze these bacteria to “determine the composition of the bacterial communities in different biliary stents, their interactions with each other and which bacteria most often occur.”

Members of the HZI Microbial Pathogenicity department examined the material in biliary catheters that had been removed from patients and replaced by new ones. HZI researchers collaborated with the Surgery Clinic of the Braunschweig General Hospital and the Department of Internal Medicine of the Klinikum Salzgitter. The latter is “the most specialized and experienced clinic for biliary stent replacement in the region, where each week patients receive new biliary stents,” according to the researchers.

“This had the advantage that we could compare a huge set of samples,” said Dietmar Pieper, group leader, Department of Microbial Pathogenesis. “This huge set of samples could only be analyzed, as we did not try to culture the bacteria on plates, but used sophisticated culture-independent methods.”

Though Pieper explained that there were differences in the patients—and as a result, the bacterial colonies that formed—the researchers were able to see, in general, common colonies. The next step in the research is to examine how different environmental factors, such as lifestyle, impact the bacteria colonies.

“With these results, an important cornerstone was laid towards the development of new methods and medications,” said Pieper.