sentence: The aim of this study was to evaluate the in vitro effect of single antibiotic ( ciprofloxacin , ceftazidime , or ampicillin ) treatment on adherence of Escherichia coli and Enterococcus to plastic stents .
paragraph: In vitro evaluation of antibiotic prophylaxis in the prevention of biliary stent blockage. Bacterial adherence and biofilm formation are important factors in the blockage of biliary stents. Clinical studies with oral antibiotic prophylaxis to prevent stent blockage have produced conflicting results. The aim of this study was to evaluate the in vitro effect of single antibiotic ( ciprofloxacin , ceftazidime , or ampicillin ) treatment on adherence of Escherichia coli and Enterococcus to plastic stents . ### methods Selected clinical isolates of E coli and Enterococcus were perfused through a modified Robbins device containing segments of polyethylene stents. The stents were removed daily and the number of bacteria attached was measured. The effect of antibiotic treatment on bacterial adherence was tested by the perfusion of individual antibiotics into separate modified Robbins devices using a side-arm adaptor and the results were compared with saline controls. ### results Compared with the saline controls, ciprofloxacin and ceftazidime caused a 10- to 100-fold reduction in the number of E coli attached to the stents, whereas ampicillin had no effect on adherence of E coli. ampicillin caused a 5- to 10-fold reduction in Enterococcus adherence but there was no change with ceftazidime. Sustained reduction in E coli adherence was observed with prolonged ciprofloxacin perfusion. ### conclusion Timely treatment with appropriate antibiotics reduced bacterial adherence in vitro and may be potentially beneficial in the prevention of stent blockage.