Molecular Epidemiology of Candida Auris Outbreak in a Major Secondary-Care Hospital in Kuwait

Abstract

The emerging, often multidrug-resistant Candida auris is increasingly being associated with outbreaks in healthcare facilities. Here we describe the molecular epidemiology of a C. auris outbreak during 18 months, which started in 2018 in the high dependency unit (HDU) of a secondary-care hospital in Kuwait. Demographic and clinical data for candidemia and colonized patients were prospectively recorded. Clinical and environmental isolates were subjected to phenotypic and molecular identification; antifungal susceptibility testing by broth microdilution method; PCR-sequencing of ERG11 and FKS1 for resistance mechanisms to triazoles and echinocandins, respectively; and molecular fingerprinting by short tandem repeat (STR) analyses. Seventy-one (17 candidemic and 54 colonized) patients including 26 with candiduria and seven environmental samples yielded C. auris. All isolates were identified as C. auris by Vitek2, MALDI-TOF MS, PCR amplification and/or PCR-sequencing of rDNA. Twelve candidemia and 26 colonized patients were admitted or exposed to HDU. Following outbreak recognition, an intensive screening program was instituted for new patients. Despite treatment of all candidemia and 36 colonized patients, 9 of 17 candidemia and 27 of 54 colonized patients died with an overall crude mortality rate of ~50%. Nearly all isolates were resistant to fluconazole and contained the Y132F mutation in ERG11 except one patient’s isolates, which were also distinct by STR typing. Only urine isolates from two patients developed echinocandin resistance with concomitant FKS1 mutations. The transmission of C. auris in this outbreak was linked to infected/colonized patients and the hospital environment. However, despite continuous surveillance and enforcement of infection control measures, sporadic new cases continued to occur, challenging the containment efforts.