Species Identification, Virulence Factors, and Antifungal Resistance in Clinical Candida Isolates from ICU Patients

<i>Candida</i> spp. are important opportunistic human fungal pathogens. This study aimed to identify and characterize <i>Candida</i> spp. obtained from patients admitted to an Intensive Care Unit (ICU), focusing on virulence attributes and susceptibility to antifungal agents. A total of 131 isolates from oral and tracheobronchial secretions of adult ICU patients were evaluated. Phenotypic identification was performed using chromogenic culture media for <i>Candida</i>, followed by MALDI-TOF mass spectrometry, with representative isolates confirmed by ITS sequencing. Antifungal susceptibility to fluconazole, ketoconazole, and amphotericin B was determined only by the agar disk diffusion method, and virulence was assessed through esterase, DNase, protease, and hemolytic activity assays. <i>C. albicans</i> was the prevalent species, followed by <i>C. tropicalis</i>, <i>C. krusei</i>, <i>C. glabrata</i>, <i>C. parapsilosis</i>, <i>C. dubliniensis</i>, <i>C. lusitaniae</i>, and <i>C. guilliermondii</i>. Antifungal resistance rates reached 51.1% for fluconazole, 42.7% for ketoconazole, and 19.1% for amphotericin B, as determined by disk diffusion method. Overall, 64.9% of the isolates exhibited esterase activity, 18.3% DNase, 45.8% protease, and 67.2% exhibited hemolytic activity. Oral isolates were more frequent than tracheal isolates and demonstrated a higher prevalence of antifungal resistance and virulence traits. These findings underscore the epidemiological importance of characterizing <i>Candida</i> species in hospitals to better understand the yeast profile and to support adequate clinical management.