CliniCon Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Candida auris: the yeast of our worries.... (93543)  (93744)

Christopher H. Heath 1 2
  1. Department of Microbiology, PathWest Laboratory Medicine, Murdoch, Western Australia, Australia
  2. Department of Infectious Diseases, Fiona Stanley Hospital, Murdoch, Western Australia, Australia

Candida auris is a globally emerging multi-drug resistant yeast that was first identified in 2009. The organism has been found on six continents and appears to be spreading rapidly. Strains arise from one of 5 distinct clades, that have arisen independently. In 2015, my colleagues and I treated the first case of C. auris infection in Australia (EID, 2019;25:192-4). Currently, as of the end of 2022, AURA surveillance data showed only 20 isolates in Australia from all jurisdictions excepting, the ACT and Tasmania. Conversely, return of travel has been associated with 4 isolates in Western Australia (WA) during the first 3-months of 2023. Traditional laboratory methods were associated with high rates of misidentification, although, MALDI-TOF MS technology in most diagnostic laboratories has resolved most challenges. C. auris is associated with frequent nosocomial outbreaks overseas, partly because patient colonization is prolonged and eradication from fomites in patients’ rooms is difficult-to-impossible to ensure. C. auris is also frequently resistant to most environmental antiseptics, making eradication from the hospital setting difficult. Most isolates in Australia have arisen from either southern Africa or the Indian sub-continent clade strains. Cases in WA have been mostly linked to repatriation of patients from hospitals in southern Africa. Disease caused by invasive C. auris infections is associated with a high clinical impact; for candidaemia, crude mortality rates are ~50%. Most isolates are azole-resistant (fluconazole >80%), ~25% Amphotericin B resistant, 2-5% Echinocandin resistant. Indeed, some strains of C. auris are pan-antifungal drug (registered) resistant, although, agreed MIC breakpoints are pending. New antifungals such as ibrexafungerp, manogepix, and rezafungin appear promising. Phylogenetics and whole genome sequencing (WGS) has shown several interesting facets to the biology of this MDR-pathogen, including high genome plasticity and clade specific evolutionary trajectories. Currently, further benchmarking/validation of WGS data from all C. auris clades is required, because there is higher variability between pipelines when trying to infer clonality from epidemiologically linked isolates. Controversies exist regarding the evolution of C auris, postulated factors include, excessive azole use - integrating, clinical/environmental usage, global warming and specific environmental habitats. Future challenges and potential mitigation strategies will be briefly appraised.