Biological and genomic analyses of Clavispora sputum sp. nov., a novel potential fungal pathogen closely related to Clavispora lusitaniae (syn. Candida lusitaniae) and Candida auris

Several human fungal pathogens, including drug-resistant <i>Candida auris</i> and species of the <i>Candida haemulonii</i> complex, have emerged over the past two decades, posing new threats to human health. In this study, we report the isolation and identification of a novel species belonging to the genus <i>Clavispora</i>, herein named as <i>Cl</i> <i>avispora</i> <i>sputum</i>, from a clinical sputum sample of a COVID-19 patient. <i>Cl</i> <i>. sputum</i> is phylogenetically closely related to fungal pathogens <i>Clavispora lusitaniae</i> (syn. <i>Candida lusitaniae</i>) and <i>C. auris</i>. When grown on CHROMagar <i>Candida</i> Plus medium, <i>Cl. sputum</i> exhibited a similar coloration to <i>C. auris</i> strain CBS12372. <i>Cl. sputum</i> was able to develop weak filaments on CM medium. Although <i>Cl. sputum</i> and <i>Cl. lusitaniae</i> are phylogenetically closely related, comparative genomic and synteny analyses indicated significant chromosomal rearrangements between the two species. Although <i>Cl. sputum</i> could not grow at 37 °C under regular culture condition, an increased fungal burden in the lung tissue of a mouse systemic infection model implies that it could be a potential opportunistic pathogenic yeast in humans.