Fruits are vehicles of drug-resistant pathogenic Candida tropicalis

Abstract

ABSTRACT Candida tropicalis is the leading cause of non-albicans candidemia in tropical/sub-tropical areas. We detected a predominant genotype of azole-resistant C. tropicalis clinical strains in Taiwan from 2014 to 2018. To investigate the potential fomite transmission of drug-resistant C. tropicalis , we characterized yeasts recovered from 17 samples sourced from 6 different kinds of fruits from a supermarket in northern Taiwan in the present study. Fruits were gently washed with buffer, and the solution was then collected for centrifugation. The cell suspension was plated onto CHROMagar Candida medium. Representative yeast species was identified by rDNA sequencing. Drug susceptibilities of C. tropicalis were determined by the broth microdilution method. We found that different types of fruit surfaces had different distributions of yeast species. Washing fruit can significantly eliminate the number of yeasts from the surface. Of 123 identified isolates, C. tropicalis was the most frequently found species, followed by Meyerozyma caribbica and Candida krusei . Among 10 collected C. tropicalis , all 3 fluconazole-resistant ones were non-susceptible to voriconazole. Furthermore, the genotype of all azole-resistant C. tropicalis belonged to the same predominant genotype of azole-resistant C. tropicalis causing candidemia in patients in Taiwan. Hence, fruit can serve as a vehicle of azole-resistant C. tropicalis and other species, especially C. krusei , which is intrinsically resistant to fluconazole. IMPORTANCE Of 123 identified isolates from the fruit surface, C. tropicalis was the most frequently found species, followed by Meyerozyma caribbica and Candida krusei . All three fluconazole-resistant C. tropicalis were non-susceptible to voriconazole and belonged to the same predominant genotype of azole-resistant C. tropicalis causing candidemia in patients in Taiwan. Our findings provide evidence that fruit should be washed before eaten not only to remove chemicals but also potential drug-resistant pathogenic microbes, especially for immunocompromised individuals. To keep precious treatment options in patients, we not only continuously implement antimicrobial stewardship in hospitals but also reducing/stopping the use of agricultural fungicide classes used in human medicine.