Phenotypic and Genotypic Characterization of Candida auris, an Emerging Pathogen Isolated from Blood

Abstract

Introduction:Candida auris has been reported from various health care settings and has recently gained importance because of its intrinsic resistance to many classes of antifungal agents and to disinfection. The outbreak potential and high mortality associated with Candida auris infection reinforces the need for speciation. Routine conventional methods are cumbersome and automated systems are unable to confirm up to species level. Materials and Methods:Candida auris isolates from consecutive non-repetitive blood cultures over a 1-year period were speciated based on phenotypic, physiological and biochemical tests and VITEK. Molecular confirmation was done by PCR-RFLP and MALDI-TOF. Anti- fungal susceptibility test was performed according to CLSI guidelines (2021), using suitable controls. Virulence factors such as production of Hemolysin, Phospholipase, Esterase and Bio-film production were demonstrated. RT-PCR was used to screen the COVID-19 status using SD-Biosensor kit. Baseline data and clinical history were collected and analysed. Results: Of 3632 blood cultures (0.77%), 28 Candida sp. were isolated including 9 Candida auris, (9/28, 32.14%). Of these 8 were from COVID-19 positive patients (88.89%), while 1 was from COVID-19 negative patient (11.11%). Two patients survived, while the remaining 7 patients succumbed to the disease. Conclusion: The increasing incidence of Candidiasis especially during the COVID-19 pandemic has raised the concern for early speciation. Through multi-modal strategies such as quick and correct identification, active surveillance, guided reporting, stringent infection control measures and correct use of anti-fungals through proper susceptibility testing, we can prevent the occurrence and spread of new Candida auris cases in the future.