Microbiological Aspects in Biofilm Produced by some Uropathogens Isolated from Patients with Indwelling Bladder Catheters

Seventy five catheter urine specimens obtained from sixty four patients and admitted to Urology and other departments in Ramadi Teaching Hospital were studied. qualitative and quantitative detection for biofilm production for all isolates were achieved. Antimicrobial susceptibility test for planktonic cells of study isolates was performed by broth dilution method and the MICs were detected. Further, In Vitro model for formation of pseudomonal biofilm on catheter segments by biofilm producer-isolates of the same bacteria was achieved. BICs and MBECs were detected for all sessile study isolates of Pseudomonas aeruginosa against ciprofloxacin, amikacin and cefotaxime.
Out of 75 catheter urine specimens, 61 (81.4%) were positive for culture including: Escherichia coli 17 (27.9%) followed by Klebsiella spp. 13 (21.3%), Pseudomonas aeruginosa 12 (19.7%), and in spectrophotometric method, the results showed that all of 12 isolates of Pseudomonas aeruginosa, 7 isolates of Proteus mirabilis, 17 isolates of Escherichia coli and 13 isolates of Klebsiella, 12 (100%), 7 (100%), 12 (70.6%) and 12 (92.3%) isolates produced biofilm in the glucose supplemented media. In biofilm antimicrobial susceptibility, the sessile study isolates of Pseudomonas aeruginosa were required 10-50 X MICs from ciprofloxacin and amikacin to inhibit bacterial biofilm and 50-100 X MICs to eradicate it from the surfaces of catheter in contrast to cefotaxime of which BICs were from 50-100 X MICs and MBECs from 100-1000 X MICs.
The study concluded that Escherichia coli was the most common uropathogen followed by Klebsiella spp., and Pseudomonas aeruginosa.. Also, all study isolates of Pseudomonas aeruginosa and Proteus mirabilis produced biofilm qualitatively and quantatively. Further, with regard to ciprofloxacin and amikacin, the study isolates were also required 10-50 X MICs to inhibit bacterial biofilm and 50-100 X MICs to remove pseudomonal adhesion from the catheters while those for cefotaxime were 50-100 X MICs and 100-1000 MICs for inhibition and eradication of bacterial biofilm respectively.