Pilot Study on Septifast PCR for the Early Diagnosis of Invasive Fungal Infections in Neutropenic Patients with Acute Leukemia
Background: Invasive Fungal Infections (IFI) are life-threatening complications in neutropenic patients with Acute leukemia (AL). The diagnosis of IFI is challenging because of the lack of specificity of clinical signs and the low sensitivity of cultures. This results in a large empirical use of antifungal agents. Septifast (Roche), a new PCR-based blood assay for detection of bacterial and fungal DNA in patients with sepsis, may contribute to the early diagnosis of IFI during neutropenia. Objective: To assess the efficiency of Septifast PCR for the diagnosis of IFI in neutropenic patients with AL. Method: Pilot observational prospective study. Blood samples for Septifast PCR were drawn in adult febrile neutropenic patients with AL at onset of fever and twice weekly during persistent fever. IFI were classified as proven, probable or possible according to the EORTC-MSG criteria. The efficiency of Septifast PCR for the diagnosis of IFI was compared to that of clinical assessment (EORTC-MSG criteria). Results: One hundred and three samples were analyzed during 65 febrile episodes in 34 patients. 7 (11%) episodes were classified as probable or possible IFI (3 probable candidiasis, 2 probable aspergillosis, 2 possible IFI). No fungemia was detected by blood cultures. Septifast PCR detected fungi in 6 febrile episodes as shown in the table. Using EORTC-MSG criteria as gold standard for the diagnosis of IFI, sensitivity of Septifast PCR was 71%, specificity 98%, PPV 83%, NPV 97% and efficiency 95%. Septfiast PCR positivity preceded the diagnosis of IFI by EORTC-MSG criteria in 3/4 cases and start of empirical antifungal therapy in 1/4 cases. Conclusions: This pilot study suggests that Septifast PCR blood assay may be an efficient tool for the early diagnosis of invasive mycoses in neutropenic patients with acute leukemia. Excellent test' s specificity and negative predictive value might contribute to targeted use of antifungal therapy.
Full conference title:
15th International Symposium on Infections in the Immunocompromised Host