PCR-Mediated Early Diagnosis of Fungal infections in Patients with Living-Donor Liver Transplants

Abstract

Fungal infections are frequently observed in living-donor liver transplantation (LT) and are correlated with the clinical outcome. Early diagnosis of fungus infection is difficult because of the low positive rate of blood culture and the poor specificity of the (1-3)-β-D-glucan assay for fungi. A polymerase chain reaction (PCR)-based method was developed for the early diagnosis of fungal infection. The PCR-based method consists of a two step PCR amplification from peripheral blood samples; the first PCR which detects all species of fungi excluding Mucor, Fusarium and Sporothrix (fungi-specific PCR). Subsequently, nested PCRs is used to determine the species of fungi (species-specific PCR), Aspergillus/Penicillium (ASP/PEN), Candida albicans/parapsilosis/tropicals/ guliermondi (CAN), Candida glabrata (C.glab.), and broad spectrum of fungi (Broad spectrum). This method was applied to peripheral blood samples from 31 LT patients, 11 samples from febrile patients in hematological ward (HW), and 15 patients with fever of unknown origin in the general ward (GW). Fourteen of the LT patients were tested positive with the fungi-specific PCR, 22 with the species-specific PCR. The positive rates of species-specific PCR were 12.9% for ASP/PEN, 29.0% for CAN, 9.7% for C.galb. and 45.2% for the broad spectrum, respectively. Five of the HW patients tested positive with the fungus specific- PCR, and 6 with the species-specific PCR. Two of the GW patients were positive with the fungi-specific-PCR. The fungus-specific PCR has higher specificity than the (1-3)-bete-D-glucan measurement, and the clinical outcome of LT patients correlated significantly with the results of this method. In conclusion, that the newly developed PCR-based method might be useful for early detection and diagnosis of fungus infection in LT patients.