Identification and Antifungal Susceptibility Patterns of Candida Strains Isolated From Blood Specimens in Iran

Background: In the past two decades, the incidence of fungal infections has significantly increased worldwide. Despite treatment with a broad range of antifungal agents, nosocomial candidemia is associated with high mortality rates and resistance to antifungal agents is becoming increasingly prevalent in Candida species. Therefore, detection and identification of pathogens at the species level and antifungal susceptibility testing are essential to select the appropriate antifungal therapy. The incidence of candidemia and the antifungal susceptibility patterns of the associated strains have not been extensively studied in Iran. Objectives: The current study aimed to assess the microbial epidemiology of candidemia and the antifungal susceptibility profiles of Candida isolates. Patients and Methods: Out of 5141 blood culture specimens analyzed in Iran, 48 specimens from 32 patients were yeast-positive. The isolates were precisely identified at the species level using the well-established phenotypic polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The yeasts were also tested for antifungal susceptibility to fluconazole, itraconazole, ketoconazole, voriconazole, and caspofungin using the broth microdilution method. Results: Candidaparapsilosis (C. parapsilosis) was the most common yeast pathogen isolated (34.4%), followed by Candida glabrata (C. glabrata) (28.1%), Candida albicans (C. albicans) (25%), Candida tropicalis (C. tropicalis) (9.4%), and Candida kefyr (C. kefyr) (3.1%). Candida glabrata was isolated more often in elderly patients ( > 60 years old). Conclusions: The results of antifungal susceptibility tests demonstrated that voriconazole was the most active drug against Candida isolates. Candida albicans is the most common yeast isolated from human blood world-wide; the unexpectedly higher rate of C. parapsilosis isolated in this study necessitates more studies with larger sample sizes in Iran