Purpose: We sought to determine the composition and initiation site of bacterial biofilm on indwelling urinary catheters and to track biofilm progression with time.
Materials and methods: Indwelling urinary catheters were collected from 2 tertiary care centers following removal from patients. Indwelling time was noted and catheters were de-identified. Catheters were sectioned, stained for biofilms and analyzed by spectrophotometry and visualization. Biofilm colonization patterns were analyzed using descriptive statistical analysis and bacterial composition was determined using next generation sequencing.
Results: We collected and analyzed a total of 33 catheters from 26 males and 7 females with indwelling time ranging from 15 minutes to 43 days. Biofilm colonization was consistently high on the region of the balloon for all indwelling times. After week 1 the distal third of the catheter had higher biofilm colonization than the proximal third (week 2 p=0.034). At all indwelling times the intraluminal surface of the catheter had greater biofilm colonization than the outer surface. Next generation sequencing detected potential uropathogenic bacteria in all 10 analyzed samples.
Conclusions: The catheter balloon, its distal aspect and its lumen were the predominant locations of biofilm comprising uropathogenic bacteria. Strategies to prevent or treat biofilm should be targeted to these areas.
Keywords: biofilms; urethra; urinary catheters; urinary tract infections; uropathogenic Escherichia coli.