Virulence factors of Candida spp. isolated from COVID-19 patients: hydrolytic enzyme activity and biofilm formation

During the coronavirus disease 2019 (COVID-19) pandemic, an increased prevalence of Candida co-infections has been reported. However, data on the virulence factors of Candida spp. isolated from COVID-19 patients remain scarce. This study aimed to assess the virulence factors of Candida spp. isolated from COVID-19 patients and to explore their potential associations with clinical parameters. A total of 71 Candida (C.) strains were analyzed, representing four species: 49 (69.01%) C. albicans strains, 14 (19.71%) C. glabrata strains, 7 (9.85%) C. tropicalis strains, and 1 (1.40%) C. dubliniensis strain. The activities of proteinase, phospholipase, and hemolysin, as well as biofilm-forming capacity, were evaluated. All C. albicans strains and 21 (95.45%) non-albicans Candida (NAC) strains produced proteinase. Phospholipase activity was detected in 46 (93.87%) C. albicans strains and 10 (45.45%) NAC strains. High hemolytic activity was observed in all Candida strains. Biofilm formation was detected in 31 (43.66%) Candida strains, with variable intensities. These findings highlight high levels of hydrolytic enzyme activity among Candida spp. isolated from COVID-19 patients and contribute to the growing understanding of Candida pathogenesis in immunocompromised populations, providing insights for patient management.