The isolation of Aspergillus fumigatus from respiratory tract specimens in heart transplant recipients is highly predictive of invasive aspergillosis

Background. Prompt recognition of invasive pulmonary aspergillosis (IPA) after heart transplantation is essential for achieving a successful outcome. However, the significance, of the isolation of Aspergillus from respiratory specimens in heart transplant recipients is not established. Methods. From 1990 to 1999, we analyzed first respiratory specimens with Aspergillus spp. growth from heart transplant patients in our institution. All specimens were cultured in both fungal and conventional media. Diagnosis of proven and probable IPA or colonization was made according to criteria of the Mycoses Study Group. Results. During the 10-year study period, Aspergillus spp. was recovered from 30 episodes from 27 heart transplant recipients (incidence: 10.5%). Three episodes were classified as indeterminate and were included in the analysis in a double way, first considering them as true positives and afterward as true negatives, so ranges were obtained. After applying diagnostic criteria, 18 of 30 episodes were proven or probable IPA, and 9 episodes were colonizations. Accordingly, 7 to 8% of heart transplant recipients suffered an IPA, and the overall positive predictive value (PPV) was 60% to 70%. When analyzed by species, the PPV of recovering Aspergillus fumigatus was 78% to 91%, whereas it was 0% for other species. The PPV increased to 88% to 100% when A. fumigatus was recovered from a respiratory specimen other than sputum and decreased to 50% to 67% when it was recovered from sputum. The sensitivities of fungal and conventional media for the recovery of Aspergillus spp. were 95% to 100% and 33% to 38%, respectively. Conclusion. The isolation of A fumigatus from the respiratory tract of a heart transplant recipient is highly predictive of invasive aspergillosis.