Candida Auris Biofilms in an Ex Vivo Porcine Dermal Model

Candida auris, a drug-resistant yeast, has recently been reported infecting patients in hospitals and nursing homes worldwide. With the increased attention this pathogen has received, and the overall concerns due to high mortality related to infections caused by this yeast, we have developed an ex vivo porcine dermal biofilm model to evaluate C. auris biofilm formation within a wound-relevant matrix.

The data presented here shows growth of C. auris (AR-0384) on the sterilized porcine dermal matrix over the course of 72 hours. The inoculated explants were challenged with 25x MIC or 50x MIC of amphotericin B present in the agar on which the explants are incubated. At every 24-hour time point, a portion of the explants was recovered to evaluate overall microbial load. In addition, at each 24-hour time point, a portion of the explants were further treated for 24 hours in full strength media containing 150 µg/mL (200x MIC) of amphotericin B at 35°C to determine the tolerance of these biofilms to a treatment with a traditional antifungal agent.

Overall, within 24-hour incubation time, C. auris forms a fairly robust biofilm with up to eight logs of microbial load. Furthermore, treatment of pre-formed biofilms with amphotericin B, even at these high concentrations (200x MIC), only reduced the microbial load by two logs at most. These data collectively show that the ex vivo model is suitable for establishing biofilms of C. auris in a model relevant for the wound care application, and the biofilms formed here exhibit high tolerance to treatment with traditional antifungal agents.