Immunoperoxidase staining in the recognition of Aspergillus infections

This study concerns the use of the indirect immunoperoxidase technique for labelling Aspergillus species in infected human and animal tissues in smears taken from cultures. Specific labelling without serious cross-reactivity with Candida species or Zygomycete fungi was demonstrated using antiserum to Aspergillus. However, it was not possible to distinguish between two Aspergillus species. A fumigatus and A. flavus with this technique. Pretreatment of sections with sodium azide and normal swine serum was effective in eliminating background staining. The method can be used to produce permanently stained sections and has applications in the recognition of hyphal fragments in tissue from infected patients.