Molecular Identification and Antifungal Susceptibility Profiles of Non-albicans Candida Species Clinical Isolates

Abstract

Background: There is an increasing incidence of life-threatening systemic mycoses, specifically fulminant infections by the Candida species in hospitalised patients and in those who are immunocompromised. Management of the limited number of antifungal drugs currently available requires the identification of infections containing drug-resistant isolates. Objectives: The aim of this study was to identify the non-albicans Candida species as azole-resistant fungi, isolated from sputum and bronchoalveolar lavage specimens of hospitalised cases. Methods: The subjects included hospital-acquired infection (HAI) cases, with a primary diagnosis using a direct microscopic examination, performed for the detection of probable fungi. The molecular tests of PCR-restriction fragment length polymorphism (RFLP) and real-time PCR were performed to confirm the identity and molecular typing of the Candida isolates. Antifungal susceptibility testing (AFST), by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BMD) minimum inhibitory concentration (MIC) (M27-A2) method, was performed on the hospital-isolated Candida species. Results: During 24 months, from August 2014 to September 2016, a total of 198 samples were obtained from cases with proven HAI. The results of experimental studies on the specimens showed 93 (47%) positive cases for a fungal or bacterial infection, of which 54 (58%) had a fungal infection. It was hypothesised that all of the isolated organisms were causative agents of the HAI. Conclusions: The results showed that the medium CHROMagar™ Candida is an accessible and easy-to-use method for the identification of infection, but not as accurate and reliable as PCR-RFLP and real-time PCR methods. Results also showed decreasing susceptibility to azoles (itraconazole in this study) of the Candida species.