Objectives: To evaluate the applicability of in situ hybridization (ISH) technique with a species-specific DNA probe in the specific diagnosis of clinical systemic Aspergillus infections. Materials & Methods: Sixteen Formalin-fixed and paraffin-embeded surgical tissue specimens from 16 patients in whom the diagnosis of Aspergillus spp. infections were made or suspected were studied by the ISH technique with a DNA probe from the alkaline proteinase (ALP) gene with the length of 465bp. The DNA probe was synthesized and digoxigenin-labeled by means of polymerase chain reaction (PCR). Eight cases were bronchial or lung infections, 1 was renal infection, 7 were nasal cavity or paranasal sinuses fungal infections. Eight formalin-fixed and paraffin-embeded surgical tissue specimens from other fungal infections including 3 of the Cryptococcosis, 2 of the candidiosis, 2 of the Actinomycosis, 1 of the Fusariosis were selected as the negtive controls. Results: The in situ hybridization assay for detecting Aspergillus ALP gene produced positive stain within the fungal hyphae in 13 of the 16 cases suspected Aspergillus infections including the renal infection of Aspergillus flavus, but in none of the infections with other fungi. The organisms invading tissues were intensely stained, weak or no staining within the Aspergillomas. Conclusion: The ISH is a sensitive specific technique for detecting systemic Aspergillus infections. According to the homology search in Genbank, the DNA probe is highly specific for Aspergillus fumigatus and have lower homologies with Aspergillus flavus, therefore we concluded that the ISH with this probe could differentiate the two common species from other Aspergillus spp. or from non-Aspergillus fungi in tissue specimens. It could be applicable to clinical pathological molecular diagnosis of Aspergillus infections.
Full conference title:
The 15 th Congress of the International Society for Human and Animal Mycology
- ISHAM 15th (2003)