MOLECULAR AMBIGUITIES IN HOSPITAL SURVEILLANCE: Hyphopichia burtonii MISLABELED AS Candida auris BY PCR AND SELECTIVE MEDIA

Accurate environmental surveillance of Candida auris, also known as Candidozyma auris, is critical for infection control but remains hampered by diagnostic limitations regarding environmental yeasts. This study evaluated the performance of screening methods in a hospital in Southern Brazil, analyzing 52 high-touch surface samples. We report the isolation of a yeast strain from a patient bed rail that mimicked C. auris across multiple diagnostic tiers: it grew under selective conditions (40°C, 10% NaCl), exhibited high fluconazole resistance (MIC 128 μg/mL), and generated a specific PCR amplification band (∼163 bp). While biochemical (API 20C) and VITEK® MS systems misidentified the isolate as C. guilliermondii and C. lusitaniae/haemulonii with high confidence, Bruker MALDI-TOF and ITS sequencing correctly identified it as Hyphopichia burtonii. To elucidate the mechanism of the molecular false positive, in silico genomic analysis was performed, revealing that H. burtonii possesses over 900 conserved binding sites for the standard C. auris primers within its repetitive rDNA array. These findings demonstrate that reliance on phenotypic traits and endpoint PCR can lead to serious diagnostic errors due to the ubiquity of conserved domains in environmental species. We advocate for the integration of genetic sequencing in surveillance protocols to distinguish C. auris from environmental mimics and ensure accurate epidemiological data.