Biofilms on indwelling urologic devices: microbes and antimicrobial management prospect

Biofilms (BFs) are a potential source of highly resistant infections, frequently formed on devicesand pose problems for management.

This study was to develop rational approach for prevention of indwelling urologic device associated biofilm colonization.

From randomly selected patients visiting Department of Urology of a tertiary hospital in India 150 uro catheters and 31 used ureteric stents, in-situ for > 30, were collected aseptically. The organisms were isolated and identified from washed devices dipped in broth. Evidence of bacteriuria in each case was checked by semi-quantitative method of urine culture, on day 0 and 14 of device use. The BF statuses of the device-adhered organisms were confirmed by modified method of Christensen. The antibiotic susceptibility was determined by disc diffusion method. Data were analyzed using the Graphpad Prism version 5 statistical software.

Both single and multi-species BFs were formed on catheters, whereas mono-bacterial BFs were exclusive on stents. Predominant organisms were Pseudomonas aeruginosa (30.67%,69/225,) followed by Staphylococcus aureus (15.11%, 34/225), Escherichia coli (13.78%, 31/225), Klebsiella pneumoniae (12%, 27/225), Staphylococcus epidermidis (8.44%, 19/225). Of all strains, (89.33%, 201/225) were found to be BF positive and their colonizations were early indicated by the presence of insignificant bacteriuria in follow-up urine samples. All BF isolates were resistant to at least three antibiotics.

BF colonization was almost inevitable in prolonged used urinary devices and the most frequent organisms were Pseudomonas, Staphylococcus, and Escherichia spp. Their colonizations usually were indicated by insignificant bacteriuria from follow-up samples. Such BF dislodged organisms were multidrug resistant and could be a source of disseminated infection, yet were in-vitro preventable by many drugs.