Evaluation of a LightCycler PCR Assay for the Detection of Invasive Aspergillosis in Pediatric Patients with Onco-hematological Diseases

C. Stenghele, E. Franchin, E. Calore, R. Manganelli, I. Cerbaro, R. Cusinato, G. Tridello, S. Cesaro*.

Author address: 

Clinic of Pediatric Hematology Oncology, Via Giustiniani 3, 35128 Padova, Italy

Abstract: 

Background: Invasive Aspergilosis (IA) is associated with high mortality. Successful outcome with treatment is linked to early diagnosis, but cutture and histotogy are late positive, whereas ctinicatradiotogical signs do not arrow a certain diagnosis. Objective: To evatuate the rote of LightCycter PCR in the early diagnosis of IA in pediatric patients who underwent high doses of chemiotherapy or hematopoietic stem cell transptantation; furthermore, to evatuate sensitivity, specificity, PPV and NPV of LightCycler PCR compared to ELISA test for detection of gatactomannan antigen (GM test). Methods: 96 patients (mean age 10 years) at high risk for fungal infection or with suspected fungal infection underwent clinical, radiological and microbiological evaluations from January 2004 to October 2005. Microbiotogica[ evatuations inctuded GM test and LightCycler PCR test for fungal DNA in brood. A total of 579 brood samptes were corrected and examined by LightCyc[er PCR with FRET (Fluorescence Resonance Energy Transfer) technique, a very specific method. Results: 9/96 (9.4%) patients developed IA, c[assifted as 5 proven, 3 probabte and 1 possibte (EORTC/MSG criteria). Sensitivity, specificity, PPV and NPV of LightCyc[er PCR were respectively 87.5%, 56.32%, 15.55% and 98% when 1 positive sampte was sufficient to consider the test positive, and 62.5%, 86.2%, 29.41% and 96.15% when at [east 2 positive samptes were required to consider the test positive. Sensitivity, specificity, PPV and NPV of GM test were respectively 50%, 96.2%, 57.14% and 95.06% when 1 positive sample was sufficient to consider the test positive, and 50%, 100%, 100% and 95.23% when at [east 2 positive samptes were required to consider the test positive. Considering a positive resutt from GM or LightCycter PCR test (and 2 consecutive positive samptes as criterium for positivity), the sensitivity, specificity, PPV and NPV were 75%, 85.18%, 33.33% and 97.18% respectively. Conclusions: LightCyc[er PCR had a good sensitivity and a high NPV: if negative, IA is unlikely; GM test is Less sensitive but has a higher specificity and PPV than PCR. One possible future scenario is the combined use of both tests to design a strategy of pre-emptive antifungaL therapy in order to select the patients who do not need of early empirical treatment.
2006

abstract No: 

S104

Full conference title: 

14th International Symposium of Infections in the Immunocompromised Host
    • ISIIH, 14th