Vol 7, No 4 (2005)
Published online: 2006-02-06
Biomedical materials. Part II: Assessment of the adhesion of Escherichia coli to biomedical materials in an original dynamic flow system
Chirurgia Polska 2005;7(4):252-266.
Abstract
Background: The aim of this study was an assessment of the adhesion of the E. coli bacterium to urological
stents most often used on the American market in dynamic flow systems.
Materials and methods: The following urological stents were examined: 1. Silicone Stent® Cook Urological - a pure silicone stent, 2. Tecoflex® (Circon ACMI) - a modified polyurethane stent, 3. Percuflex® (Boston Scientific) - a stent made of a patent-protected material consisting of polythene and polypropylene with a heparinized outer layer. The experiment was carried out in an original flow chamber according to the authors’ design. The stents were put in urine infected with E. coli after establishing the optimal bacterium concentration in the inoculate, and were then rolled on agar. A bacterial enumeration was performed on the base of sonification, enzymatic (β-galactozydase activity) and fluorescent methods (Bac-Light LIVE/DEAD reagents).
Results: The time taken to achieve the dynamic balance in creating the biofilm, the optimal bacterial concentration in the inoculate as well as the optimal time of sonification were established. The number and survival rate of the bacteria and bacterial adhesion to the examined stents were assessed. Standard methods of bacterial enumeration were compared, the methodology being based on the enzymatic activity of β-galactozydase.
Conclusions: A Tecoflex® stent was characterized by three times (2.6) less bacterial adhesion, while the Percuflex stent had the highest number of bacteria on the biofilm per length of unit of the stent. A statistically significant difference in the adhesion of the E.coli bacterium between the silicone and Percuflex stents was not found.
Materials and methods: The following urological stents were examined: 1. Silicone Stent® Cook Urological - a pure silicone stent, 2. Tecoflex® (Circon ACMI) - a modified polyurethane stent, 3. Percuflex® (Boston Scientific) - a stent made of a patent-protected material consisting of polythene and polypropylene with a heparinized outer layer. The experiment was carried out in an original flow chamber according to the authors’ design. The stents were put in urine infected with E. coli after establishing the optimal bacterium concentration in the inoculate, and were then rolled on agar. A bacterial enumeration was performed on the base of sonification, enzymatic (β-galactozydase activity) and fluorescent methods (Bac-Light LIVE/DEAD reagents).
Results: The time taken to achieve the dynamic balance in creating the biofilm, the optimal bacterial concentration in the inoculate as well as the optimal time of sonification were established. The number and survival rate of the bacteria and bacterial adhesion to the examined stents were assessed. Standard methods of bacterial enumeration were compared, the methodology being based on the enzymatic activity of β-galactozydase.
Conclusions: A Tecoflex® stent was characterized by three times (2.6) less bacterial adhesion, while the Percuflex stent had the highest number of bacteria on the biofilm per length of unit of the stent. A statistically significant difference in the adhesion of the E.coli bacterium between the silicone and Percuflex stents was not found.
Keywords: bacterial adhesiondynamic flow systemurological stentsEscherichia coli
