A real time PCR assay on blood for diagnosis of invasive candidiasis in immunocompromised patient

Background and Purpose: Invasive candidiasis (IC) is a significant cause of morbidity and mortality in patients with hematologic disorders and bone marrow transplant recipients. Rapid, specific and sensitive test for the timely accuracy in immunocompromised patients to reduce mortality rates and prevent IC progress is necessary. We established a real-time PCR assay on blood for the diagnosis and differentiation of the causative Candida species. Materials and Methods: Whole blood samples were collected twice, from ۷۲ patients for Real Time PCR and blood culture assays. The primers and hybridization probes were designed to potentiate the specific sequence of ۱۸S rRNA genes using Light Cycler system and Fluorescence Resonance Energy Transfer (FERT). The patients with hematologic malignancies and bone marrow transplant recipients were evaluated for IC based on the revised European Organization for Research and Treatment of Cancer/ Mycoses Study Group (EORTC/MSG) criteria. Results: From ۲۰۰۹ to ۲۰۱۱, ۷۲ patients with hematologic malignancies and bone marrow transplant recipients were evaluated for IC. The female to male ratio was ۲۷:۴۵; the mean age was ۳۲.۱ years. The most common malignancy in this patient was acute myeloid leukemia (AML) (۲۷.۸%) and acute lymphoblastic leukemia (ALL) (۲۶.۴%). Out of ۷۲ patients, ۱۱ patients (۱۵.۳%) had positive real time PCR /probe results. Based on the melting temperature (Tm) analysis, ۵ (۴۵.۴%) C. krusei, ۳ (۲۷.۲%) C. tropicalis, ۲ (۱۸.۱%) C. parapsilosis and ۱ C. albicans (۹%) were identified. According to the revised EORTC / MSG, ۱ patient (۹%) and ۱۰ patients (۹۱%) were defined as proven and possible groups of IC, respectively. The mortality rate in proven and possible IC patient was found ۵۴.۵%. Conclusion: The established Real-time PCR/FRET probe assay is an appropriate diagnostic tool for the detection of Candida species DNA and the management of patients suffering from hematologic malignancies and bone marrow recipient are at risk for IC.