Endoscopy 2020; 52(S 01): S301
DOI: 10.1055/s-0040-1704960
ESGE Days 2020 ePoster presentations
Colon and rectum 09:00–17:00 Thursday, April 23, 2020 ePoster area
© Georg Thieme Verlag KG Stuttgart · New York

MICRO- AND MACROFLUIDIC ASSAYS FOR BIOFILM FORMATION ON BILIARY STENTS: PRELIMINARY RESULTS OF A PILOT STUDY

R Rusconi
1   Humanitas University, Department of Biomedical Sciences, Pieve Emanuele, Italy
,
A Fugazza
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
,
A Capogreco
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
,
A Bruno
3    Humanitas Clinical and Research Center – IRCCS, Rozzano, Italy
4   Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering, Milano, Italy
,
C Cardenas
3    Humanitas Clinical and Research Center – IRCCS, Rozzano, Italy
4   Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering, Milano, Italy
,
M Piergiovanni
4   Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering, Milano, Italy
,
G Dubini
4   Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering, Milano, Italy
,
S Carrara
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
,
R Maselli
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
,
A Anderloni
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
,
A Repici
1   Humanitas University, Department of Biomedical Sciences, Pieve Emanuele, Italy
2   Humanitas Research Hospital, Digestive Endoscopy Unit, Rozzano, Italy
› Author Affiliations
Further Information

Publication History

Publication Date:
23 April 2020 (online)

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Aims Data on biofilm formation and basic mechanisms of stent occlusion in function of different type of stents are lacking. The aim of this study was to investigate biofilm formation in two model assays which reproduce two fundamental physical features of the stents: geometry and fluid flow.

Methods The microfluidic approach was exploited in order to reproduce smooth channels, in a macrofluidic approach representing smooth plastic stents(PS) involved six samples of different size of PS(7,8.5,10 Fr), and micro-patterned channels, reproducing the mesh of uncovered metal stents(UMS); Three clinically relevant bacterial strains, i.e., Pseudomonas Aeruginosa(PA), Enterococcus faecalis(EF) and Klebsiella oxytoca(KO), were tested in both cases to assess their ability of surface colonization and biofilm formation.

Results Preliminary results have shown that micro-patterned surfaces promoted a quicker and slightly higher bacterial coverage compared to the smooth ones in the same flow conditions; in particular, experiments with PA displayed a 60% increase in the growth rate and 140% in the production of biomass. Moreover, the biofilm seemed to concentrate along the walls and in the niches resulting from the intersection of the mesh pattern, while it developed uniformly on the flat surface. Macrofluidic experiments have shown a correlation with the device dimension for both bacterial species(EF, KO): the stent with the smallest diameter promoted the highest bacterial density per unit internal surface. Moreover, it was observed a stronger attachment of KO with respect to EF, regardless the type of stent. The mean optical density per unit surface area recorded with KO doubling the values of EF (0.042 in PS and 0.06 in UMS vs 0.018 and 0.03).

Conclusions Our preliminary data show that biofilm’ formation is related to environmental conditions such as the material and dimension of the biliary stents. Further studies are needed for confirming these results in order to prevent microbiological colonization and stent occlusion.