Candida tropicalis infection is strongly associated with the presence of biofilms in urinary catheters. Thus,the aim of this work was to study the behaviour of C. tropicalis in biofilms of different ages (24e120 h)formed in artificial urine (AU) and their effect in human urinary bladder cells (TCC-SUP). Reference strainATCC 750 and two isolates from patients with candiduria (U69 and U75) were used in this study. Theadhesion to human cells was evaluated after 2 h of contact with Candida biofilms, using the Crystal violetstaining method, and the human cells response was evaluated in terms of activity inhibition and celldamage. Candida tropicalis aspartyl proteinase (SAPT) gene expression was determined by real-time PCR.Candida tropicalis biofilm cells were able to adhere to TCC-SUP cells. The highest extent of yeastattachment was obtained for the 72 h old biofilm cells. Yeasts affected TCC-SUP cells, with 120 h-biofilmcells causing the highest levels of cell injury. Generally, SAPT3 was highly expressed and SAPT4 was onlydetected in the reference strain. Overall, it is important to highlight that C. tropicalis cells detached frombiofilms are able to colonize human cells and cause some injury and reduction of metabolic activity.
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