Early plasma cell-free DNA diagnosis of fatal Acanthamoeba granulomatous amebic encephalitis in a liver transplant recipient

Background

Acanthamoeba granulomatous amebic encephalitis (GAE) is a rare, highly lethal opportunistic infection in immunocompromised hosts. Diagnosis is difficult because clinical and radiographic findings are nonspecific and conventional cerebrospinal fluid (CSF) studies may be nondiagnostic. Case: We report a 68-year-old woman who developed fever, seizures, and progressive encephalopathy 13 days after orthotopic liver transplantation. Brain MRI demonstrated multifocal supratentorial and infratentorial enhancing lesions with vasogenic edema and peripheral diffusion restriction. Initial CSF bacterial, viral, and fungal studies were negative. Plasma microbial cell-free DNA (mcfDNA) sequencing identified Acanthamoeba species 5 days after admission, prompting expedited Centers for Disease Control and Prevention (CDC) consultation and initiation of multidrug anti-amoebic therapy. CDC CSF real-time PCR subsequently confirmed Acanthamoeba infection. Despite antimicrobial escalation and reduction of immunosuppression, cerebral abscesses, progressive edema and uncal herniation developed and the patient died.