Diagnosis of Invasive Fungal Infections by a Real-Time Panfungal PCR Assay in Pediatric Patients Undergoing Intensive Chemotherapy or Allogeneic Stem Cell Transplantion.

Abstract 343

Invasive fungal infections are life threatening events in severely immunocompromised patients, and there is urgent need for reliable screening methods facilitating rapid and broad detection of pathogenic fungi. We have established a two-reaction real-time PCR assay permitting highly sensitive detection and quantitative monitoring of more than 80 fungal pathogens, covering a large spectrum of moulds, yeasts and Zygomycetes (European patent No. 06817468.9). To assess the clinical potential of the panfungal real-time PCR assay, more than 600 consecutive specimens from 126 pediatric patients carrying a high risk of invasive fungal infections were analyzed. The results revealed an excellent correlation between PCR positivity and the presence of proven, probable or possible fungal infection according to the criteria of the European Organization for Research and Treatment of Cancer (EORTC), indicating a sensitivity of the assay of 96% (95%CI: 81-99.3%). Hence, the negative predictive value of the panfungal PCR assay presented is very high, and our current data indicate that molecular screening of patients during febrile neutropenic episodes by the assay can help prevent unnecessary toxicity resulting from empirical antifungal treatment in individuals who may not be at risk of imminent fungal disease. The specificity of the assay in the test cohort of patients was in the range of 76% (95%CI:62-87%), and the observations indicate that rapid species identification may be required to assess the positive predictive value for impending fungus-related disease. The availabel data provide a basis for appropriately designed clinical studies addressing the full diagnostic potential of fungal screening by highly sensitive, broad- spectrum molecular assays in severely immunocompromised patients.