培養陰性Gemella haemolysans心内膜炎の新規診断法としての微生物由来無細胞DNAシーケンシング

Infective endocarditis (IE) is a known complication of repaired congenital heart disease. Blood culture-negative endocarditis (BCNE) remains a diagnostic challenge, often delaying pathogen-directed antimicrobial therapy.

We report a 5-year-old girl with a repaired partial atrioventricular canal defect who presented with intracranial hemorrhage from a ruptured cerebral aneurysm. Transthoracic echocardiography revealed a mitral valve vegetation concerning for IE, although multiple blood cultures remained negative. Plasma microbial cell-free DNA (mcfDNA) sequencing subsequently identified Gemella haemolysans. She underwent emergent neurosurgical and endovascular intervention followed by targeted antimicrobial therapy, with subsequent neurological recovery.

This case illustrates the utility of mcfDNA sequencing in the diagnosis of BCNE, particularly in the context of rare and fastidious organisms such as Gemella. Early diagnosis enables pathogen-directed treatment and highlights the importance of advanced molecular diagnostics in pediatric IE.

Plasma mcfDNA sequencing can facilitate diagnosis of BCNE, guiding targeted therapy.