UBC Theses and Dissertations
Efficacy of novel coating in preventing Proteus mirabilis adherence and assessing the pathogenic mechanisms utilized to potentiate catheter-associated urinary tract infections Khoddami, Sara
Introduction: Proteus mirabilis is a gram-negative, urease-positive bacterium that infects the urinary tract and is linked with catheter-associated urinary tract infections (CAUTIs). CAUTIs are painful, and both physically and financially burdensome infections that are associated with the presence of a urinary catheter that drains urine from the bladder. The insertion of a catheter allows for entry and scaffolding of bacteria, such as P. mirabilis to adhere to and propagate infection in the urinary tract. Methods: In vitro experiments assessed the ability of a novel anti-fouling catheter coating to prevent P. mirabilis adhesion. Coated and uncoated catheters were exposed to bacteria and adherence was quantified via colony-forming units (CFU) counts. In vivo studies utilized a mouse model implanted with coated or uncoated catheters and inoculated with P. mirabilis. Furthermore, adherence of wildtype and mutant P. mirabilis strains to catheters were conducted by co-incubating samples in artificial urine and bacteria; adherence was quantified via CFU counts. Cellular adhesion and invasion assays were utilized to observe wildtype, mutant, and complemented P. mirabilis associations with uroepithelial cells. Briefly, cells were exposed to different strains of P. mirabilis and co-cultured; for adhesion assays, cells were washed, lysed, and plated for CFU counts. For invasion assays: cells were treated with antibiotics to eliminate extracellular bacteria, then washed, lysed, and plated for CFU counts. In vivo experiments assessed bladders, urine, and catheters in mice infected with different P. mirabilis strains. Results: In vitro and in vivo results indicated increased adherence and invasion abilities in wildtype P. mirabilis, compared to mutant strains. Specifically, wildtype was the only strain able to invade uroepithelial cells at 24 hours post-infection. Furthermore, our novel anti-adhering coating significantly reduced bacterial attachment to catheters both in vitro and in vivo. Conclusion: We have shown our novel coating to be highly effective in preventing bacterial adherence both in vitro and in vivo. Moreover, we have observed wildtype P. mirabilis to be capable of invading and adhering to uroepithelial cells at an increased capacity, compared to mutant strains. Through gaining greater insight into the pathogenic mechanisms utilized, we can target and diminish P. mirabilis CAUTIs.
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