الفهرس 
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Abstract
One hundred and forty nine selected bacterial clinical isolates (suggestive for Staphylococcus, E. coli, Pseudomonas and Proteus species) were screened for biofilm formation using microtiterplate assay. Only isolates that showed strong or moderate capabilities to produce biofilm and belonged to E. coli, Pseudomonas and Proteus species were further evaluated for their adherence to Foley latex urinary catheters. Seven isolates that showed the highest biofilm values and strong adhesion to urinary catheters were selected, identified as Pseudomonas aeruginosa (P4&P38), Escherichia coli (E6& E206& E208) and Proteus mirabilis (P11& P16) and used for the completion of this study.
Adhesion of the tested isolates to Foley latex urinary catheters was found to be greatly affected by growth phase, incubation temperature and pH and the effect was both bacterial species and strain dependent. All-silicone, hyDROPhilic coated silicone and siliconzed PVC catheters reduced the adhesion of the seven tested isolates. Urea and uric acid caused pronounced reduction of bacterial adhesion; calcium oxalate reduced adhesion of the tested P. mirabilis isolates. Pre-treatment of catheter segments with urine of physiologically normal individual increased bacterial adhesion. Time course experiments showed that adhesion of the tested E. coli, P. aeruginosa and P. mirabilis isolates is growth associated, non growth associated and both growth and non growth associated, respectively.
Thirty seven agents were screened for their capabilities to inhibit biofilm formation of the tested isolates. Only five agents (poloxamer 188, EDTA, ciprofloxacin, cefotaxime and gentamicin) were proved to have anti-biofilm activities against the tested isolates at the tested concentration(s). These agents were further evaluated for their effect on bacterial cell surface hyDROPhobicity and capabilities to prevent bacterial adhesion as well as to eradicate pre-formed biofilm on Foley latex urinary catheters. Poloxamer 188 (0.5%) and EDTA (0.05 M) caused pronounced reduction of bacterial cell hyDROPhobicity of almost all tested isolates. Complete eradication of pre-formed biofilms on Foley latex urinary catheters was observed in case of EDTA, ciprofloxacin, gentamicin and cefotaxime in almost all of the tested isolates.
Coating of the Foley latex urinary catheters using the impregnation technique was done using; ciprofloxacin, gentamicin, cefotaxime and EDTA. Ciprofloxacin-impregnated and gentamicin-impregnated catheters showed superior antimicrobial activity over other tested agents-impregnated catheters against E. coli isolate E6, P. aeruginosa isolate P4 and P. mirabilis isolate P11. The formed coat by some tested agents (ciprofloxacin, cefotaxime and gentamicin) was retained after being exposed to TSB for 48 h in adhesion assay.