Candida parapsilosis complex is an emerging opportunistic pathogen associated with bloodstream infections and healthcare‑associated outbreaks, particularly in intensive care units. Rising antifungal resistance underscores the need for continuous surveillance. This multicenter study assessed the in vitro susceptibility of eight antifungal agents against clinical, environmental, and healthcare worker isolates of the C. parapsilosis complex and investigated potential molecular mechanisms of resistance. A total of 2,600 samples were collected between May 2023 and December 2024, including 2,180 clinical specimens, 330 environmental samples, and 90 hand swabs from healthcare workers. From these, 527 C. parapsilosis isolates were recovered. Identification was performed using conventional and molecular approaches. Antifungal susceptibility testing followed CLSI M27 (4th edition) guidelines. Isolates exhibiting resistance were further analyzed by sequencing the ERG11 and FKS1 genes. Among the 527 isolates, 510 originated from clinical settings, 6 from reusable breast pump sets, and 11 from healthcare worker hands. Overall, 10 isolates (1.9%) demonstrated resistance according to CLSI breakpoints, all of which were clinical in origin. Resistance was detected to fluconazole (0.38%), caspofungin (0.95%), and combined caspofungin–anidulafungin resistance (0.57%). The MIC values for fluconazole and caspofunginwere 4 µg/mL, indicating reduced susceptibility among clinical isolates. Voriconazole, clotrimazole, and amphotericin B exhibited strong in vitro activity. No resistance‑associatedmutations were identified in ERG11 or FKS1. Despite the absence of detectable ERG11 or FKS1 mutations, reduced susceptibility to azoles and echinocandins was observed, primarily among clinical isolates. Environmental and healthcare worker isolates showed lower MIC values, suggesting minimal antifungal selection pressure outside patient care environments. These findings point to emerging antifungal resistance in C. parapsilosis clinical isolates in Iran and emphasize the importance of ongoing surveillance and molecular monitoring to inform therapeutic and infection control strategies. However more studies are required to correlate these findings with clinical outcomes.
Moslemi et al. (Wed,) studied this question.