Reviewed by Jen Cihlar, DO, Vanderbilt University Medical Center
Bottom line: Fluconazole resistant C. tropicalis clade 4 causing Candidemia has been linked to the same fluconazole resistant C. tropicalis clade 4 found in the environment/orchards which could be serving as a reservoir. C. tropicalis susceptibility to fluconazole correlated with susceptibilities to commonly used agricultural azole fungicides.
As part of national disease monitoring system in Taiwan, an increasing number of fluconazole-resistant Candida tropicalis belonging to a clade 4 genotype have been isolated from patients with Candidemia in the Asia-Pacific region. The authors analyzed 704 yeasts from sampling fruit, soil, water, worker armpit, hand and mouth swabs across 80 orchards in Taiwan. The most common pathogenic yeast species recovered from farmers were Candida albicans (14.7%) and C. parapsilosis (11.6%) whereas C. tropicalis (13.0%), C. palmioleophila (6.6%), and Pichia kudriavzevii (6.0%) were prevalent among 453 environmental isolates. Notably 18.6% (11/59) of C. tropicalis from the environment were resistant to fluconazole, and 81.8% (9/11) of those belonged to the clade 4 genotype with a resistance mechanism that corresponded to commonly used agricultural azole fungicides throughout the region. The epidemiologic detection and prevalence of same clade 4 genotype of fluconazole-resistant C. tropicalis from agricultural sites and infected humans suggests that fluconazole-resistant C. tropicalis in environments can be a threat to healthcare and serve as a potential reservoir. The clinical cases they describe had no identifiable hospital link and most patients had not been treated with azole drugs in the prior 6 months before admission. This reinforces the concept of One Health and further investigation for stewardship efforts in both hospitals and environmental settings alike.
Reference: Tseng K, Chen Y, Zhou Z, et al. Detection in Orchards of Predominant Azole-Resistant Candida tropicalis Genotype Causing Human Candidemia, Taiwan. Emerging Infectious Diseases. 2024;30(11):2323-2332. doi:10.3201/eid3011.240545.