Leitbakteria of microbial biofilm communities causing occlusion of biliary stents

Abstract

Biliary stents inserted to relieve obstructive jaundice caused by biliary or pancreatic malignancies inevitably become occluded by microbial growth in the form of diverse microbial community biofilms. The scarce information available on these communities is based on cultivation methods, but such methods usually provide distorted overviews of community composition, so commonalities and differences in biliary stent communities are uncertain. We extracted DNA and RNA from the microbial communities of 11 biliary stents explanted from nine patients in hospitals from two different countries, amplified 16S rRNA and rDNA sequences, analysed the amplicons by the single-strand conformation polymorphism (SSCP) method, and sequenced and deduced phylogenetic assignments of the major amplicons representing the major biofilm community members. We used a Modified Robbins Device (MRD) to study de novo development of a stent biofilm from a patient stent microbial community. Single-strand conformation polymorphism fingerprinting revealed the same six abundant bacterial species, here designated Leitbakteria, namely Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Enterobacter aerogenes, and two unculturable bacteria distantly related to E. coli and Shigella sonnei, in all of the stent biofilm communities. In the experimental biliary stent system, a sequential colonization of the stent surface was observed, with P. aeruginosa being the pioneer colonizer, followed by K. pneumoniae and one of the unculturable Leitbakteria, followed by the remainder of the community. The overview of microbial biofilm communities of biliary stents gained by the use of culture-independent methods revealed new unculturable bacteria as major members of biliary stent biofilms, and the diversity of the abundant members of the stent biofilms is considerably lower than suggested from earlier studies based on cultivation methods, and that communities from different stents from different patients in different countries are remarkably similar and have similar major members, the stent Leitbakteria.

Reduction in diversity of the colonic mucosa associated bacterial microflora in patients with active inflammatory bowel disease

“…To identify the bacteria correlated to the bands, selected bands from the polyacrylamide gel after silver staining were excised with sterile scalpels and processed as described elsewhere. 52 59 The sequencing reaction was performed on an ABI PRISM 3700 *Patients without suspicious macroscopic or histological findings (n = 20), patients with diverticulosis (n = 7), and patients with polyps (n = 4). ÀPatients with undetermined colitis (n = 2), unclear diarrhoea (n = 5), infectious diarrhoea (n = 7), and patients with radiation colitis (n = 1).…”

Feasibility evaluation of chitosan coatings on polyethylene tubing for biliary stent applications

“…The endoscopic insertion of plastic and/or metallic biliary stents is one of the medical treatments that can relieve the obstructive jaundice caused by biliary or pancreatic malignant tumors 1, 2. It is a useful method for patients, such as the elderly, who cannot tolerate surgery 3.…”

“…However, inserted plastic stents are restricted by the occlusion of the stents: replacing them in 3–5 months is necessary 5. Although the precise mechanism of the blockage is still unknown, it is generally believed that protein adsorption, adherence of bacteria, formation of biofilms, and precipitation of biliary sludge (composed of bacteria, proteins, calcium bilirubinate, etc 1, 6, 7…”

“…1). A prospective method of preventing the blockage is to reduce the bacterial adhesion and biofilm formation with a useful stent material or by the modification of the surfaces of existing plastic stents 1, 8–11. Moreover, live Escherichia coli , being capable of producing β‐glucuronidase in bile, can deconjugate bilirubin glucuronide effectively, and this leads to the precipitation of calcium bilirubinate 6, 11.…”

Retraction

“…Since the appearance of the article ‘ Leitbakteria of microbial biofilm communities causing occlusion of biliary stents’ (Wenderoth et al. , 2003), inconsistencies in the results reported have been detected which raise doubts about some of the conclusions drawn.…”