Kodamaea ohmeri: An emergent yeast from a One Health perspective

Abstract

Kodamaea ohmeri is an emerging and opportunistic yeast associated with a high mortality rate in humans. As it is commonly found in the environment, it is possible that environmental conditions and agricultural practices contribute to the adaptation of this yeast and the selection of antifungal resistance. During a multicentric study in Brazil, conducted under a One Health perspective, 14 isolates of K. ohmeri were identified from different sources: three from blood cultures, three from animals (swine and poultry), and eight from animal environments (swine and poultry). Yeasts were isolated using CHROmagar® Candida medium and identified by MALDI-TOF MS and ITS rDNA barcoding. Minimum inhibitory concentration (MIC) was determined using the broth microdilution method for clinical (azoles, echinocandins, pyrimidine analogs, and polyenes), and environmental antifungals (tebuconazole, pyraclostrobin, carbendazim, and mancozeb), and hospital disinfectants (quaternary ammonium compounds). Of note, color variations of K. ohmeri were noted on CHROmagar® depending on the incubation time, which is likely to complicate its identification. Following polyphasic identification and taxonomic confirmation, all isolates demonstrated low MIC values for clinical antifungals, disinfectants, and tebuconazole. However, all isolates were able to grow in the presence of carbendazim, mancozeb, and pyraclostrobin. Together, these findings highlight the risks associated with the use of environmental azoles, such as tebuconazole, as they may impact non-target fungi of medical importance, but other fungicides do not present the same risk. This is the first study to demonstrate that K. ohmeri, an important emerging yeast in human medicine, can be isolated from various sources, including patients. Although the isolates exhibited low MIC values for clinical antifungals, it is crucial to monitor changes in sensitivity patterns over time in emerging microorganisms to prevent the development of multidrug resistance, which may originate in the environment.