Diagnosis of pulmonary aspergillosis using optical brighteners

Abstract

Invasive pulmonary aspergillosis (IPA) is increasingly recognized especially in immunocompromised patients, but early diagnosis remains a problem. Fungal elements in clinical specimens can be directly stained with an optical brightener. The high intensity of the elicited fluorescence allows for rapid and reliable microscopic screening. In the present study the authors aimed to validate this method. All specimens from bronchial secretions or pleural fluid suspected of mycosis (n=94) and all bronchoalveolar lavages (n=439) were prospectively evaluated by culture and staining with the optical brightener Blankophor-P-Flüssig. IPA was diagnosed for 17 specimens from 13 patients, using a combination of clinical, culture and radiological data, and by biopsy (n=3) or autopsy (n=3). The overall incidence of IPA was 3.3%. Nine of the 13 patients with IPA died (mortality=69%). Staining with the optical brightener and consecutive microscopic screening took 9+/-3 min. For the diagnosis of invasive aspergillosis, sensitivity was 0.88 and specificity was 0.99. Using culture, sensitivity was 0.76 and specificity was 0.99. In conclusion, direct examination of clinical specimens using the optical brightener has a high diagnostic potential for the diagnosis of invasive pulmonary aspergillosis. The reliability, simplicity and speed of the method render it suitable for routine diagnostic work.