Objective To investigate the sensitivity and specificity of two-step PCR in detection of aspergillus species in blood from malignant hemotopoietic tumor patients. Methods Forty-one blood samples from patients at high-risk for invasive fungal disease were detected by two-step PCR. The clinic applicability of two-step PCR for systemic aspergillosis diagnosis was assessed by analyzing computed tomography, aspergillus culture, neutropenia and outcome after anti-fungal therapy. Results Specific band of PCR was obtained from aspergillus strains and the products of PCR had a high homogeneous in sequence with aspergillus species. Sixteen of 41 patients were PCR positive, aspergillosis was proven in 4 of these patients by the results of culture. The controls (12 healthy) were all PCR negative. The eight patients (of the 16 PCR positive patients) had characteristic high-resolution computed tomography findings that suggested invasive aspergillosis. The minimum value of white blood cell (WBC) was 0.3x 109/LÂ±0.14x 109/L in PCR positive patients, whereas, was 0.5x 109/L Â±0.26x 109/L in PCR negative patients (p=0.0326). The duration with WBC count less than 1.0x 109/L was 19Â±8.313 days and 12.69Â±6.945 days respectively between two groups (p=0.0472). After antifungal therapy, one of the patients with PCR positive died of chemotherapy-related early death. Conclusions The two-step PCR assays allows for the highly sensitive and specific detection of aspergillus pathogens in vitro and in vivo. A specific two-step PCR assay for the rapid detection of the aspergillus species in blood samples improves early diagnosis for systemic aspergillosis and helps us to make decision for antifungal therapy.
Full conference title:
47th American Society for Haematology
- ASH 47th (2005)