Emerging Candida species isolated from renal transplant recipients: Species distribution and susceptibility profiles

Candidiasis is a major challenge among renal transplant recipients (RTRs) worldwide and is associated with high morbidity and mortality rates. Fluconazole is the most commonly used agent for Candida infections. However, frequent relapse and treatment failure are still reported among patients affected with this infection. In the present study, Candida species obtained from RTRs were characterized based on conventional and molecular assays. Furthermore, the antifungal susceptibility profiles of these species were determined. This study was conducted on a total of 126 RTRs within 2012-2016. The patients were categorized according to the referenced diagnostic criteria. The identification of Candida species was accomplished based on conventional examination, assimilation profile test, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The minimum inhibitory concentrations (MICs) of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin were determined based on the guidelines of Clinical and Laboratory Standards Institute. The patients with Candida infection were diagnosed with urinary tract candidiasis (n = 17), peritonitis (n = 8), intra-abdominal candidiasis (n = 6), candidemia (n = 4), hepatosplenic candidiasis (n = 3), and Candida pneumonia (n = 3). A total of 41 Candida isolates, including C. albicans (n = 18), C. famata (n = 8), C. kefyr (n = 4), C. tropicalis (n = 4), C. parapsilosis (n = 3), C. glabrata (n = 2), and C. lusitaniae (n = 2), were isolated from 32.5% (41/126) renal transplant recipients. Fluconazole-resistance was observed in seven isolates, entailing C. albicans (n = 6) and C. tropicalis (n = 1). Fluconazole MIC for C. lusitaniae isolates was above the epidemiologic cut-off value (4-16 μg/ml). Furthermore, MIC range values of fluconazole against C. famata and C. kefyr were obtained as 4-32 μg/ml and 4-8 μg/ml, respectively. Posaconazole exhibited potent activity against Candida isolates, followed by caspofungin. The identification of Candida species, together with susceptibility testing, provides important data about the geographic trends of the fluconazole-resistance profiles of Candida species. It is necessary to maintain a consistent method for the implementation of early diagnosis and adoption of treatment regimen.