2889. Skin Niche Conditions Trigger C. auris to Form Robust Biofilms That Resist Desiccation

BACKGROUND: Emerging pathogen Candida auris, the first fungus to be labeled as a public health threat, causes nosocomial outbreaks of invasive candidiasis with mortality as high as 60%. Little is known about the pathogenesis of this species that has newly arisen in the last 10 years. It is unclear why this species readily colonizes the skin and transmits efficiently in healthcare settings. We considered the possibility that C. auris may proliferate in conditions of the skin niche. METHODS: We analyzed the growth of C. auris (B11203) in synthetic sweat media that was designed to mimic human axillary sweat. We included C. albicans SC5314 as a comparison. To simulate sweat evaporation, we examined fungal growth in sweat media that had been concentrated up to 2.5-fold. We utilized OD600 readings to quantify planktonic and biofilm growth. Biofilm architecture was assessed by scanning electron microscopy. To determine the resilience of biofilms, biofilm viability was assessed by viable burden following desiccation. RESULTS: In the various concentrations of sweat media, C. auris formed biofilms that were 3.5- to 5-fold greater that those observed for C. albicans (A). In contrast, C. auris biofilms formed in RPMI-MOPS were approximately half the density of the C. albicans biofilms. During planktonic growth in synthetic sweat media, C. auris and C. albicans replicated similarly, including in media that had been concentrated 2.5-fold. This suggests that the various media conditions differently trigger biofilm formation for the two species. The C. auris biofilm formed in sweat media was approximately 100-fold more resistant to 1 week of desiccation (B). CONCLUSION: Skin niche conditions trigger C. auris to form resilient biofilms that resist desiccation. We propose that this unique characteristic may account for the propensity of this species to colonize the skin and for its capacity to persist on the surface of contaminated medical devices. [Image: see text] DISCLOSURES: All Authors: No reported Disclosures.