Abstract
Bacterial colonization of biliary stents is one of the driving forces behind sludge formation which may result in stent occlusion. Major focus of the study was to analyze the spectrum and number of microorganisms in relation to the indwelling time of stents and the risk factors for sludge formation. 343 stents were sonicated to optimize the bacterial release from the biofilm and identified by matrix-associated laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF). 2283 bacteria were analyzed in total. The most prevalent microorganisms were Enterococcus species (spp.) (504;22%), followed by Klebsiella spp. (218;10%) and Candida spp. (188;8%). Colonization of the stents mainly began with aerobic gram-positive bacteria (43/49;88%) and Candida spp. (25/49;51%), whereas stents with an indwelling time>60 days(d) showed an almost equal colonization rate by aerobic gram-negative (176/184;96%) and aerobic gram-positive bacteria (183/184;99%) and a high proportion of anaerobes (127/184;69%). Compared to stents without sludge, more Clostridium spp. [(P = 0.02; Odds Ratio (OR): 2.4; 95% confidence interval (95%CI): (1.1–4.9)]) and Staphylococcus spp. [(P = 0.03; OR (95%CI): 4.3 (1.1–16.5)] were cultured from stents with sludge. Multivariate analysis revealed a significant relationship between the number of microorganisms [P<0.01; OR (95%CI): 1.3(1.1–1.5)], the indwelling time [P<0.01; 1–15 d vs. 20–59 d: OR (95%CI): 5.6(1.4–22), 1–15 d vs. 60–3087 d: OR (95% CI): 9.5(2.5–35.7)], the presence of sideholes [P<0.01; OR (95%CI): 3.5(1.6–7.9)] and the occurrence of sludge. Stent occlusion was found in 70/343(20%) stents. In 35% of cases, stent occlusion resulted in a cholangitis or cholestasis. In conclusion, microbial colonization of the stents changed with the indwelling time. Sludge was associated with an altered spectrum and an increasing number of microorganisms, a long indwelling time and the presence of sideholes. Interestingly, stent occlusion did not necessarily lead to a symptomatic biliary obstruction.
Highlights
Endoscopic stent therapy is a well-established therapeutic approach in patients with biliary obstructive diseases [1,2,3]
Stent occlusion represents a common complication in patients undergoing stent therapy, which can result in cholestasis or cholangitis [4,5]
In a previous retrospective study [16], we could show that the incidences of Enterococcus spp. and nonfermenting bacteria were significantly higher in cholangitis episodes with biliary endoprosthesis compared to cholangitis episodes without biliary endoprosthesis
Summary
Endoscopic stent therapy is a well-established therapeutic approach in patients with biliary obstructive diseases [1,2,3]. Leung et al [10] perfused biliary stents with either bacterially contaminated or sterile bile fluid. Scan via electron microscopy demonstrated a dense layer of bacteria and amorphous material on the surface of the stents, which were perfused with bacterially contaminated bile. This phenomenon was not observed on the surface of the stents, exposed to sterile bile only. Major focus of the study was to analyze the spectrum and the number of biliary microorganisms on the surface of stents in relation to sludge, the indwelling time and the presence of sideholes on the stent surface. To optimize bacterial release from the biofilm, biliary stents were exposed to low frequency ultrasound
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
