Candida albicans Horizontal Transmission in COVID-19 Patients Hospitalized in Intensive Care Unit

Background: Invasive candidiasis is a predominant mycosis in hospitalized patients, and Candida albicans is the species most often responsible for this infection. Most candidiasis cases originate from endogenous mycobiota; therefore, Candida strains can easily be transferred among hospital patients and personnel. The aim of this study was to assess the possible horizontal transmission of C. albicans in patients with severe COVID-19 infection requiring hospitalization in the intensive care unit. Methods: In total, 59 C. albicans strains from 36 patients were collected from blood and lower-respiratory samples. The strains were genotyped using the RAPD method with the OPA-18 primer (5 '-AGCTGACCGT-3 '). Antifungal susceptibility testing was performed for amphotericin B (AMB), fluconazole (FCZ), voriconazole (VCZ), and anidulafungin (ANF) using the EUCAST method. Results: C. albicans strains were separated into 13 different groups according to their RAPD pattern. Two predominant clonal clusters of 17 strains isolated from 12 patients and 12 strains from 7 patients were identified, followed by clusters with 6, 4, and 8 strains isolated from 5, 4, and 3 patients, respectively. C. albicans strains were sensitive to AMB, FCZ, VCZ, and ANF, and antifungal susceptibility profiles were similar in all genetic clusters. Conclusions: Our study indicates that C. albicans strains can spread horizontally. The routes of transmission for strains in the ward have not been explained due to there being insufficient data. The transmission could have been caused by the unintentional spread of pathogens by medical personnel.