Increasing prevalence, molecular characterization and antifungal drug susceptibility of serial Candida auris isolates in Kuwait

Candida auris is an emerging yeast pathogen of global significance. Its multidrug-resistant nature and inadequacies of conventional identification systems pose diagnostic and therapeutic challenges. This study investigated occurrence of C. auris in clinical specimens in Kuwait and its susceptibility to antifungal agents. Clinical yeast strains isolated during 3.5-year period and forming pink-colored colonies on CHROMagar Candida were studied by wet mount examination for microscopic morphology and Vitek 2 yeast identification system. A simple species-specific PCR assay was developed for molecular identification and results were confirmed by PCR-sequencing of rDNA. Antifungal susceptibility testing of one isolate from each patient was determined by Etest. The 280 isolates forming pink-colored colonies on CHROMagar Candida, were identified by Vitek 2 as Candida haemulonii (n = 166), Candida utilis (n = 49), Candida kefyr (n = 45), Candida guilliermondii (n = 9), Candida famata (n = 6) and Candida conglobata (n = 5). Species-specific PCR and PCR-sequencing of rDNA identified 166 C. haemulonii isolates as C. auris (n = 158), C. haemulonii (n = 6) and Candida duobushaemulonii (n = 2). C. auris isolates originated from diverse clinical specimens from 56 patients. Of 56 C. auris isolates tested, all were resistant to fluconazole, 41/56 (73%) and 13/56 (23%) were additionally resistant to voriconazole and amphotericin B, respectively. Eleven (20%) isolates were resistant to fluconazole, voriconazole and amphotericin B. One isolate was resistant to caspofungin and micafungin. Increasing isolation of C. auris in recent years from diverse clinical specimens including bloodstream shows that C. auris is an emerging non-albicans Candida species in Kuwait causing a variety of infections. Inability of conventional identification methods to accurately identify this pathogen and multidrug-resistant nature of many strains calls for a greater understanding of its epidemiology, risk factors for acquiring C. auris infection and management strategies in high-risk patients. This is the first comprehensive study on the emergence of this multidrug-resistant yeast from Kuwait and the Middle East.