Emergence of Vanrija humicola as a pathogen of urinary tract infections in Korea

Vanrija humicola, a yeast belonging to Trichosporonaceae, is rarely pathogenic. All cases of isolation of V. humicola were retrospectively reviewed from 2021 to 2023. A total of four V. humicola were isolated from urine samples. Organisms cultured for 5 days at 25°C produced yellow, dry and cerebriform colonies, and were successfully identified as V. humicola using Bruker Biotyper MALDI-TOF. Two recent isolates were resistant to fluconazole, echinocandins, and flucytosine. In all 4 cases, V. humicola was sporadically isolated more than 14 days after admission. One case was presumed to be colonized. Of the other three cases that developed a urinary tract infection (UTI), only one with pancytopenia was treated for UTI by V. humicola with caspofungin, but expired 4 days later. V. humicola has emerged as a drug-resistant fungal pathogen of hospital-acquired UTI. Species identification and antifungal susceptibility testing of this organism are required for critical patients.