الفهرس | Only 14 pages are availabe for public view |
Abstract Furthermore, the MICs for P. mirabilis isolates for some biocides were determined. Chlorhexidine had MICs of 50, 100, 200 and 400 μg/ml for 16, 12, 48, and 24% of the isolates, respectively. The study also revealed that the MICs of thiomersal against Proteus isolates 30, 60 and 10 % was 0.2, 0.3 and 0.5 μg/ml, respectively against thiomersal. Povidone-iodine had MICs of 2000 and 2500 μg/ml. The MIC range of chlorocresol was 100-150 μg/ml, while MIC range of hydrogen peroxide was 100-300 μg/ml. Also, the MIC range determined for cetrimide was 50-800 μg/ml. One of the most important virulence factors that Proteus has is urease enzyme production. Urease breaks down urea in urine into carbon dioxide and ammonia; this causes a prominent increase in the urine pH and precipitation of calcium and magnesium struvite crystals. Crystal formation can lead to catheter occlusion and stone formation in the kidney. Moreover, P. mirabilis has a characteristic swarming movement that allows it to move over catheter surfaces. Also, catheters serve as an excellent surface for biofilm formation. P. mirabilis has a variety of fimbriae that cause adhesion of P. mirabilis to solid surfaces as catheters. The most studied is the mannose resistant fimbriae MR/P that allows P. mirabilis adherence to catheter surface, which is the initiating step for biofilm formation. Also, presence of MR/P fimbriae was associated with the development of pyelonephritis. In the current study, some compounds that can act as inhibitors of formation of virulence factor of P. mirabilis were tested. The test compounds studied were diclofenac sodium, ibuprofen, sodium salicylate (anti-inflammatory agents), orphenadrine (muscle relaxant), bromohexine (mucolytic), ascorbic acid (antioxidant), EDTA (chelating agent). Sub-inhibitory concentrations of each of the test compounds were screened for their ability to inhibit urease enzyme. Diclofenac, ibuprofen and sodium salicylates did not show any inhibitory effect on urease activity at concentrations 1.56, 3.125, 6.25 mg/ml, respectively. Furthermore, orphenadrine also did not show any inhibitory effect at concentrations 0.94, 1.87 mg/ml. On the other hand, bromohexine, ascorbic acid and EDTA showed inhibitory effect on urease enzyme. |