Candida Species Isolated From ICU Bloodstream Infections: Molecular Epidemiology, Antifungal Resistance, and...

In intensive care units (ICUs), bloodstream infections (BSIs) caused by Candida species pose significant clinical problems. This study aims to investigate the species distribution, virulence traits, antifungal resistance profiles, and genetic diversity of Candida isolates from patients in Indian ICUs.

100 Candida isolates were retrieved from the blood samples of ICU patients. The species were identified via molecular and microbiological techniques. Standard Clinical and Laboratory Standards Institute (CLSI)-based procedures were followed for conducting antifungal susceptibility testing. Virulence profiling involved assessing hemolytic activity, the production of hydrolytic enzymes, biofilm formation, and other characteristics linked to pathogenicity. To evaluate relatedness and potential transmission patterns, genetic typing techniques such as multilocus sequence typing (MLST) and sequencing were employed. Additionally, statistical comparisons were performed using the chi-squared test and ANOVA.

Non-albicans Candida (NAC) constituted 82% of the isolates. Candida tropicalis accounted for 39% of the species distribution, followed by Candida auris at 17%, Candida albicans at 18%, Candida parapsilosis at 10.5%, Candida glabrata at 5%, Candida krusei at 5%, and other rare species at 5.5%. Around 54% of the isolates showed fluconazole resistance, which was especially high in C. tropicalis and C. auris (p < 0.0001). About 58% were capable of strong biofilm formation, with the concentration again relying heavily on NAC paddles, which was also shown to be p < 0.0001. Four genetic clades and 29 clustered sequence types were revealed from MLST.

About 90% of resistant strains were non-albicans Candida (χ² = 78.57, p < 0.0001), and 54% of isolates of Candida, primarily C. auris and C. tropicalis, showed fluconazole resistance. The minimum inhibitory concentration (MIC) for amphotericin B was low; all isolates were susceptible to echinocandins, and voriconazole remained mainly effective. These results underscore the need for quick species identification and antifungal susceptibility testing, as well as the inadequate efficacy of empirical azole therapy in Indian ICUs. The need of the hour is frequent fungal surveillance, including colonization screening and the identification of prevalent species and susceptibility patterns at the outset to help guide focused empirical treatment. Antifungal drug resistance monitoring assists in stewardship initiatives to reduce the spread of multidrug-resistant Candida species, enhancing patient outcomes.