Molecular epidemiology, diversity, and antifungal susceptibility profiles of clinical and environmental mucorales: a five-year multicenter study in Iran (2018-2023).

Purpose: The incidence of Mucormycosis has increased during the last decades globally due to more patients being at risk for these life-threatening infections. Early diagnosis and proper selection of appropriate antifungal therapy are vital in enhancing patient outcomes. Mucorales species present a significant challenge due to their resistance to many drugs, so investigations for new therapies and strategies must be undertaken. This study elucidates the distribution and antifungal susceptibility profiles of Mucorales isolates from Iran over five years.

Methods: Species identification was performed based on morphological features and Internal Transcribed Spacer (ITS) sequences analysis. Antifungal susceptibility testing for commonly used antifungal agents was conducted following CLSI M38-A3 broth microdilution.

Results: One hundred eighty-one (116 clinical and 65 environmental) isolates were analyzed. Rhizopus arrhizus (67.9%, n = 123) and Mucor circinelloides (23.2%, n = 42) were the predominant species. The various clinical samples analyzed included sinus biopsies, nasal secretions, orbital tissues, maxilla tissues, throat, and brain tumors.

Conclusion: The lowest geometric mean minimum inhibitory concentration values were observed against the clinical and environmental isolates for amphotericin B, posaconazole, and isavuconazole. Understanding Mucorales' distribution and antifungal susceptibility patterns helps clinicians select antifungal therapies. However, further studies are warranted to correlate these findings with clinical outcomes.