Comparison of an Aspergillus Real-time Polymerase Chain Reaction Assay With Galactomannan Testing of Bronchoalvelolar Lavage Fluid for the Diagnosis of Invasive Pulmonary Aspergillosis in Lung Transplant Recipients

Abstract

BACKGROUND: Early diagnosis and treatment of invasive pulmonary aspergillosis (IPA) improves outcome. METHODS: We compared the performance of publicly available pan-Aspergillus, Aspergillus fumigatus-, and Aspergillus terreus-specific real-time polymerase chain reaction (PCR) assays with the Platelia galactomannan (GM) assay in 150 bronchoalveolar lavage (BAL) samples from lung transplant recipients (16 proven/probable IPA, 26 Aspergillus colonization, 11 non-Aspergillus mold colonization, and 97 negative controls). RESULTS: The sensitivity and specificity of pan-Aspergillus PCR (optimal quantification cycle [Cq], ≤35.0 by receiver operating characteristic analysis) and GM (≥.5) for diagnosing IPA were 100% (95% confidence interval, 79%-100%) and 88% (79%-92%), and 93% (68%-100%) and 89% (82%-93%), respectively. The sensitivity and specificity of A. fumigatus-specific PCR were 85% (55%-89%) and 96% (91%-98%), respectively. A. terreus-specific PCR was positive for the 1 patient with IPA due to this species; specificity was 99% (148 of 149 samples). Aspergillus PCR identified 1 patient with IPA not diagnosed by GM. For BAL samples associated with Aspergillus colonization, the specificity of GM (92%) was higher than that of pan-Aspergillus PCR (50%; P = .003). Among negative control samples, the specificity of pan-Aspergillus PCR (97%) was higher than that of BAL GM (88%; P = .03). Positive results for both BAL PCR and GM testing improved the specificity to 97% with minimal detriment to sensitivity (93%). CONCLUSIONS: A recently developed pan-Aspergillus PCR assay and GM testing of BAL fluid may facilitate the diagnosis of IPA after lung transplantation. A. fumigatus- and A. terreus-specific real-time PCR assays may be useful in rapidly identifying the most common cause of IPA and a species that is intrinsically resistant to amphotericin B, respectively.