Early Diagnosis of Systemic Candidiasis in Bone Marrow Transplant Recipients

Abstract

Objectives: Systemic candidiasis, are common infections during the neutropenic phase. The aim of this study was to identify quantitative Candida species ribosomal DNA using TaqMan technology for diagnosing candidiasis and monitoring them during hospitalization.

Materials and Methods: During the prospective, cross-sectional study, from September 2006 to September 2007, a total of 375 clinical blood specimens were collected from 35 patients with hematologic disorders once a week pretransplant and posttransplant. Patients were evaluated for systemic candidiasis during hospitalization. Cultures from the throat, urine, feces, and sputum, along with sonography and computerized tomographic scans, were done when patients were febrile and not having a response to antibiotics. All samples were cultured on Sabouraud dextrose agar with chloramphenicol, and direct, microscopic examination was performed. Blood samples were cultured by bedside inoculation into BACTEC medium at 35°C for 7 days. Clinical blood specimens were evaluated for Candida infections using the TaqMan-based PCR assay.

Results: Of the 35 recipients, 6 had multiple samples that were TaqMan-positive with Candida species probe, 3 had 1 PCR positive-result in their blood samples, and the 26 recipients showed negative results. Fungal rDNA was found in 2 patients before and after transplant. All 6 patients with systemic candidiasis had microbiologic and/or radiologic evidence of Candida infections.

Conclusions: It seems that TaqMan-based PCR assay can serve as an accurate method for diagnosing and monitoring Candida infections. This is the first report of its kind that shows Candida infections can be present in the blood of the bone marrow transplant candidates, so closer observation of the recipients who are neutropenic and receive immunosuppressive drugs seems warranted to improve their chances for survival.