Multidrug resistant Candida auris misidentified as C. haemulonii: Characterization by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI- XXXX MS), DNA sequencing and its antifungal susceptibility profile variability by VITEK-2, CLSI-Broth Microdilution and E-test method.

@entity281 @entity375 @entity215
UNASSIGNED: Candida auris is a multidrug resistant @entity375 that cause wide spectrum of @entity281 , especially in intensive care settings. We investigated C. auris prevalence among 102 clinical isolates previously identified as C. haemulonii or C. famata by VITEK2 system. ITS sequencing confirmed 88.2% of isolates as C. auris and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI- @entity215 ) easily separated all related species viz., C. auris (n=90), C. haemulonii (n=6), C. haemulonii var. vulnera (n=1) and C. duobushaemulonii (n=5). The in vitro antifungal susceptibility was determined using CLSI-BMD, VITEK2 AST card and Etest method. C. auris isolates revealed uniformly elevated fluconazole MICs (MIC50, 64  g/ml) and an alarming percentage of isolates (37%) exhibited elevated caspofungin MICs by CLSI-BMD. Notably, 34% of C. auris had coexisting elevated MICs (>= 2  g/ml) for both fluconazole and voriconazole and 10% of the isolates had elevated coexisting MICs (>=  2  g/ml) to two additional azoles i.e., posaconazole and isavuconazole. In contrast to reduced amphotericin B MICs by CLSI-BMD (MIC50, 1  g/ml) for C. auris, elevated MICs were noted by VITEK2, (MIC50, 8  g/ml), which were statistically significant. Candida auris remains an unnoticed pathogen in routine microbiology laboratories as 90% of the isolates characterized by commercial identification systems are misidentified as C. haemulonii. MALDI- @entity215 proved to be a more robust diagnostic technique for rapid identification of C. auris. Considering that misleading elevated MICs of amphotericin B by VITEK AST-YS07 card may lead to selection of inappropriate therapy, a cautionary approach is recommended for laboratories relying on commercial systems for identification and antifungal susceptibility testing of rare @entity375 .
