Murine model for the evaluation of candiduria caused by Candida tropicalis from biofilm

To evaluate the pathophysiology of catheter-associated candiduria, the bladders of female mice were infected with Candida tropicalis. One group was implanted with a catheter fragment with preformed biofilm by cystotomy technique, while another group received, in separate, a sterile catheter fragment and a correspondent yeast suspension. The bladder tissues were examined by histopathology and the quantity of colony forming units was evaluated. All the animals presented inflammation and the presence of C. tropicalis was observed in the tissue within 72 h of the introduction of biofilm, while 75% of the mice remained infected after 144 h. However, only 50% of animals from the group infected with C. tropicalis in suspension (planktonic yeasts), exhibited such signs of infection over time. The cystotomy technique is therefore viable in mice, and is an effective model for evaluating the pathogenesis of candiduria from catheter biofilms. The model revealed the potential of C. tropicalis infectivity and demonstrated more effective evasion of the host response in biofilm form than the planktonic yeast.