Real time polymerase chain reaction for identification of Candida species isolated from blood stream infections in non-neutropenic cancer patients

Abstract

This work aimed at identifying Candida species isolated from blood stream infection in non-neutropenic cancer patients by conventional and molecular methods. Out of 200 blood samples from cancer patients with blood stream infection, 89 were positive for Candida which were identified using chromogenic medium (CHROMagar Candida), and real-time polymerase chain reaction (RT-PCR) assays targeting the fungal ITS2 region using a LightCycler instrument. The present study revealed that nonalbicans Candida species caused most of the cases of candidaemia in the cancer patients. A total of 89 Candida isolates were obtained, Candida albicans represent 15/89 patients (16.85%) and non-albicans Candida species accounts for 74/89 patients (83.1 %) of which Candida tropicalis represent 32.6% followed by Candida parapsiliosis 23.6%, and then Candida rugosa (21,4%) and the lowest percentage was in Candida glabrata (5.6%). The results of the study revealed that real time-PCR could detect 81 out of 89 cases of candidaemia with sensitivity of 91.01%, specificity of 95.6%, PPV of 94.18% and NPV of 92.30%. The high prevalence of non-albicans candidaemia should be considered prior to antimicrobical therapy in non-neutropenic cancer patients with candidaemia. Real-time PCR represents a rapid and accurate method for diagnosis of candidaemia.