Molecular Epidemiology of Candidozyma auris within a Case Cluster in North-Central Florida: Diverse Origins and Long-Term Persistence of Strains

Background Candidozyma auris, first recognized in 2009, has emerged as a pathogen of major global concern, particularly in association with healthcare-associated infections in long-term care facilities. Methods In a study of infected and colonized patients conducted between 1/17/2023 and 11/30/2023 at our medical center in North-Central Florida, whole genome sequence data were obtained for 43 C. auris isolates from 36 patients. Results Thirteen (30%) of the 43 isolates were from cultures collected as part of an investigation of a possible infection, with blood (seven isolates) being the most common source; eight (62%) of the 13 patients with clinical infections died. Isolates were within either a Clade I monophyletic subclade associated with European and Middle Eastern strains (n=27) or were from Florida subclades within C. auris Clade III (n=16). In seven instances multiple isolates with virtually identical genetic profiles were isolated from the same patient at time intervals that ranged from three weeks to seven months, with, in some instances, intervening negative cultures. All isolates were resistant to triazoles, albeit with resistance mutations at different nucleotide positions and within different genes for Clade I and Clade III isolates. One Clade I isolate was resistant to echinocandins. Conclusions Data are consistent with a point-source C. auris outbreak involving a Clade I subclade of possible European origin, combined with multiple introductions and transmission of Clade III isolates from Florida. Strains were able to persist for extended periods of time in colonized/infected patients.