In-situ detection of Aspergillus fumigatus

An in-situ hybridisation (ISH) technique to detect Aspergillus fumigatus in infected tissues was developed in which 568-bp, 333-bp and 154-bp PCR prod ucts of the alkaline proteinase gene were employed. Dot-blot hybridisation with the 568-bp probe on a membrane containing genomic DNA from several dif ferent fungi including A. flavus A. niger. Penicillium spp,, Mucor racemosu s or Pseudallescheria boydii gave negative results. ISH was done on formali n-fixed, paraffin-embedded pulmonary tissues from rats infected with A. fum igatus and renal tissues from mice infected with A. fumigatus, A. flavus or A. niger, The 568-bp probe reacted strongly in ISH with both A. fumigatus and A. flavus, and weakly with A, niger, The 333-bp probe also reacted in I SH with A. fumigatus and A. flavus, although the intensity was weaker. Howe ver, in ISH with the 154-bp probe, there was no positive signal with any As pergillus spp, These results demonstrate that A. fumigatus and A. flavus ca n be specifically detected in infected tissues by ISH with the 568-bp probe . This technique could be applicable to clinical specimens for molecular di agnosis of aspergillus infections.