Quantitative PCR (qPCR) Detection of Mucorales DNA in Bronchoalveolar Lavage Fluid To Diagnose Pulmonary Mucormycosis

Early diagnosis and treatment are essential to improving the outcome of mucormycosis. The aim of this retrospective study was to assess the contribution of quantitative PCR detection of Mucorales DNA in bronchoalveolar lavage fluids for early diagnosis of pulmonary mucormycosis. Bronchoalveolar lavage fluid samples (n = 450) from 374 patients with pneumonia and immunosuppressive conditions were analyzed using a combination of 3 quantitative PCR assays targeting the main genera involved in mucormycosis in France (Rhizomucor, Mucor/Rhizopus, and Lichtheimia). Among these 374 patients, 24 patients had at least one bronchoalveolar lavage fluid sample with a positive PCR; 23/24 patients had radiological criteria for invasive fungal infections according to consensual criteria; 10 patients had probable or proven mucormycosis, and 13 additional patients had other invasive fungal infections (4 probable aspergillosis, 1 proven fusariosis, and 8 possible invasive fungal infections). Only 2/24 patients with a positive PCR result on a bronchoalveolar lavage fluid sample had a positive Mucorales culture. PCR was also positive on serum in 17/24 patients. In most cases, a positive PCR result was first detected using sera (15/17). However, a positive PCR on bronchoalveolar lavage fluid was the earliest and/or the only biological test revealing mucormycosis in 4 patients with a final diagnosis of probable or proven mucormycosis, 3 patients with probable aspergillosis, and one patient with a possible invasive fungal infection. Mucorales PCR performed on bronchoalveolar lavage fluid could provide additional support for earlier administration of Mucorales-directed antifungal therapy, thus improving the outcome of lung mucormycosis cases.