Coxiella burnetii infective endocarditis involving a valved right ventricle-to-pulmonary artery conduit after Rastelli repair in an adolescent: a case report

Coxiella burnetii is an important cause of blood culture-negative infective endocarditis (IE). Pediatric C. burnetii endocarditis is rare, particularly in patients with prosthetic cardiovascular materials. A 13-year-old boy with pulmonary atresia who had undergone Rastelli repair followed by replacement with a valved right ventricle-to-pulmonary artery (RV-PA) conduit presented with recurrent fever and a mobile intraconduit mass. Transthoracic echocardiography (TTE) showed a vegetation in the pulmonary valve/conduit region, and cardiac computed tomography (CT) confirmed a corresponding filling defect without periconduit abscess or pseudoaneurysm. Blood metagenomic next-generation sequencing (mNGS) detected C. burnetii, while indirect immunofluorescence assay (IFA) showed positive phase I and phase II IgG antibodies. The conduit vegetation and blood detection of C. burnetii fulfilled major imaging and microbiological criteria, respectively, under the 2023 Duke-International Society for Cardiovascular Infectious Diseases criteria. An individualized regimen of doxycycline, trimethoprim-sulfamethoxazole (TMP-SMX), and hydroxychloroquine was followed by clinical improvement and reduction in lesion size during hospitalization. C. burnetii should be considered in children with prosthetic cardiovascular materials who present with persistent fever and negative conventional blood cultures. Molecular testing, serology, and multimodality cardiac imaging can support diagnosis and early follow-up.