Identification of Candida auris isolated from blood cultures from hospital origin with different methods and evaluatoon of their antifungal susceptibility

Candida auris has emerged as a globally multidrug-resistant, healthcare- associated fungal pathogen. C.auris is increasingly isolated from patients worldwide. Recent reports have shown that misidentification of the microorganism, high rates of antifungal drug resistance, and significant patient mortality have led to difficulties in diagnosis and treatment. It is a newly identified Candida species that rapidly spreads within and between healthcare institutions due to its virulence factors that facilitate skin colonization and long- term survival in environmental environments. In this study, it was aimed to retest the strains obtained from blood cultures of intensive care patients using different methods and identified as C.auris by biochemical tests using chromogenic agar medium and molecular methods, to compare the results, and to evaluate the microdilution antifungal susceptibility profiles. Strains identified as Candida species by conventional methods were identified using BioMérieux Vitek2 compact (BioMérieux, France) and MALDI-TOFF MS BioMérieux Vitek MS v.3.2 device (BioMérieux, France). 30 C.auris strains identified as C.auris with these systems were included in the study. 30 C.auris strains were isolated from blood cultures of 26 patients. Four patients were included in the study because C.auris was isolated during their hospitalization at different times in different clinics. Of the 26 patients, 14 (53.85%) were male and 12 (46.15) were female. The highest age group was 60 and above (69.23%). The isolated strains were detected mostly in Internal Medicine Intensive Care Unit 2 clinic (36.67%) and 16 between July and September (43.33%). The value of CHROMagar Candida Plus and Real Time PCR methods in the identification of strains identified as C.auris was tested again. Colony color and morphology were evaluated and compared on Sabouraud Dextrose Aagar (SDA) and CHROMagar Candida Plus media and corn flour-Tween 80 agar. Of the 30 strains identified as C.auris by commercial systems, 26 were identified as (88.24%) C.auris by both CHROMagar Candida Plus and Real Time PCR method, 3 as (8.82%) C.parapsilosis, and 1 as (2.94%) C.tropicalis. In the antifungal susceptibility test result performed with the colorimetric microdilution method (Thermo Scientific™ Sensititre™ YeastOne™ YO9 AST Plate) (SYO; Thermo Fisher Scientific, Waltham, MA, USA), the highest resistance was detected in amphotericin B (100.00%). In conclusion, in our study, CHROMagar Candida Plus may be a useful culture method to aid in the visual identification of Candida isolates including C.auris, however, in the presence of similar yeast colonies in mixed flora samples and especially in the case of yeast group species that cause misidentification of C.auris due to closely related characteristics, MALDI-TOFF MS or Real Time PCR should be retested and identified. It is very important to determine the antifungal susceptibility profiles of the strains identified as C.auris according to CDC recommendations and using EUCAST or CLSI criteria in order to reveal resistance.