Study on invasive fungal infections in immunocompromised patients to present a suitable early diagnostic procedure

Abstract

OBJECTIVES: The incidence of invasive fungal infections has increased considerably in recent years. The aim of this study was to present a suitable early diagnostic procedure in immunocompromised patients, using a molecular assay. METHODS: From September 2005 to January 2007, 310 immunosuppressed patients were followed for fungal infections for a 6-month period. EDTA-anticoagulant whole blood specimens were collected prospectively once per week and stored at -20 degrees C until use in molecular assays. RESULTS: Molecular assays were positive in 55 (17.7%) patients. The etiologic agents were Candida albicans (67.3%), Aspergillus flavus (20.0%), Aspergillus fumigatus (7.3%), Candida tropicalis (3.6%), and Candida krusei (1.8%). The sensitivity, specificity, and positive and negative predictive values of PCR-ELISA with proven and probable invasive fungal infections were 84.6%, 92.7%, 75.3%, and 95.8%, respectively. The results showed that the mean clinical manifestation time was 38.96 days and the mean time of positivity of the molecular test (time of infection) was 17.69 days. A linear model for predicted infection and clinical manifestation time was found to be as follows: Y=11.64+1.147X, r(2)=0.812, where Y is the time at presentation of clinical signs and X is the time of infection (positive PCR-ELISA result). CONCLUSION: It may be concluded that the molecular assay would help in the diagnosis of invasive fungal infections at the early stage of infection, before clinical manifestations.