Plasma microbial cell-free DNA testing for early diagnosis of pulmonary mucormycosis in a kidney transplant recipient

Pulmonary mucormycosis is one of the most lethal invasive fungal infections encountered in solid organ transplant recipients, with mortality rates ranging from 43% to 73%. Early diagnosis is critical, yet conventional microbiologic methods including bronchoalveolar lavage cultures have limited sensitivity, and standard fungal biomarkers such as beta-D-glucan and galactomannan have no role in the detection of Mucorales species. This diagnostic gap frequently results in delayed treatment initiation, which has been associated with substantially worse outcomes. We present a case of a 67-year-old kidney transplant recipient who developed rapidly progressive pulmonary mucormycosis caused by Rhizopus microsporus in the setting of recent high-dose corticosteroid therapy for allograft rejection. Plasma cell-free DNA testing facilitated earlier diagnosis before histopathologic results returned, which contributed to successful treatment and survival in this patient with angioinvasive pulmonary mucormycosis. This case highlights the utility of plasma cell-free DNA testing in pulmonary mucormycosis and the critical importance of a multidisciplinary, combined medical-surgical approach, including early empiric antifungal therapy, aggressive surgical debridement, and immunosuppression reduction, in order to achieve disease cure.