Species characterization and antifungal susceptibility profile of yeast isolates from blood cultures of fungemic patients in Thammasat University Hospital, Thailand

Abstract

Background: Candida albicans is the most isolated fungal agent in a worldwide health system. Species distribution of Candida infection is different according to geographical regions. However, a shift in favor of non-albicans Candida species with antifungals resistance have increased as an important cause of candidemia. Objectives: This study aimed to identify the species of yeasts isolated from the blood samples of patients at the university hospital and to determine in vitro susceptibilities of three most common isolates against nine antifungal agents. Materials and methods:In total, 130 yeast isolates from 130 patients were defined the species using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Antifungal susceptibility testing was carried out using broth dilution Sensititre YeastOne panels included amphotericin B, 5-fucytosine, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, micafungin, and caspofungin. Results: The most common species in all age groups was C. tropicalis (n=48, 36.9%), followed by C. albicans (n=38, 29.2%). C. glabrata (n=23, 17.7%) was more common among elderly patients, while C. parapsilosis (n=9, 6.9%) was more frequently isolated from younger patients. Antifungal susceptibility testing in Candida species expressed MIC in the low level of almost antifungal drug except for reduced fluconazole susceptibility against C. glabrata and C. tropicalis isolates. Conclusion: C. tropicalis is the most common infection in candidemic patients. Fluconazole resistance strains were found in C. glabrata and C. tropicalis, respectively. In addition, voriconazole resistance strains were found in C. tropicalis.