Evaluation of bacterial colonization and bacteriuria secondary to internal ureteral stent.

To assess the frequency of bacterial colonization on internal ureteral stent and stent associated bacteriuria in different periods of indwelling time, a total of 100 patients (mean age 39.2+/-9.9 years, range 18-60 years, 69 male and 31 female) needing internal ureteral stent placement for different sorts of urinary tract operation in the department of Urology, Dhaka Medical College Hospital from December 2006 to May 2008 were included in the study. Sterile urine samples were obtained from each patient before stenting and all patients had been given short-term prophylactic antibiotics (5-12 days). Midstream urine obtained from each patient on the day of stent removal and submitted for microbiological culture. Stent removed by aseptic precautions. Proximal and distal stent tip segments (3-5) were also sent for culture. The median duration of stenting was 35 days (10-86 days). Bacterial colonies were found in 45% of the stent. Colonization rate was 71.4% in stents removed after 6 weeks compared to 33.3% in 4-6 weeks and 23.5% before 4 weeks (p<0.001). Bacteriuria was found only in 21% patients. Escherichia coli was the common organism isolated from both stent and urine. The study concludes that bacterial colonization significantly increases with indwelling time of stent and absence of growth in urine culture does not rule out that the stent itself is colonized.