Comparative Study of <i>Candida albicans</i> Strains from Clinical and Environmental Sources in Iran

Background: Candida species are a leading cause of fungal infections worldwide. Candidiasis, the disease caused by Candida, represents a significant public health concern globally. Candida albicans is the most common causative agent, responsible for 50 - 90% of invasive candidiasis cases. Candida albicans employs various virulence factors to adhere to, invade host tissues, and cause disease. Objectives: This study aimed to detect and compare the virulence factors of C. albicans, including hydrophobicity, biofilm formation, ergosterol content, and secretory enzymes, in clinical and environmental samples. Methods: A total of 105 clinical and 165 environmental samples suspected of containing C. albicans were collected from Imam Khomeini Hospital in Ahvaz, Iran. The isolates were evaluated for five potential virulence factors: Ergosterol content, cell surface hydrophobicity (CSH), biofilm formation, protease activity, and phospholipase activity. Results: Sixty C. albicans isolates were identified, consisting of 30 clinical and 30 environmental isolates. Biofilm production was observed in 100% of clinical isolates and 80% of environmental isolates (P < 0.001). Protease activity was detected in 66.6% of clinical isolates and 76.7% of environmental isolates (P = 0.008). Phospholipase activity was present in 60% of clinical isolates and 76.7% of environmental isolates (P = 0.262). Clinical isolates exhibited higher CSH (66.4 ± 9.8) compared to environmental isolates (47.7 ± 17.0) (P < 0.001). The ergosterol content was 1.2 ± 0.5 in clinical isolates and 1.1 ± 0.3 in environmental isolates. Conclusions: Biofilm formation was a consistent characteristic of clinical isolates, while phospholipase and protease activity were more prevalent in environmental C. albicans isolates. The results suggest possible cross-contamination between patients and the environment, as the virulence factors of clinical and environmental isolates were similar.