APCU25CR9 Abiotrophia defectiva infective endocarditis in a young male with bicuspid aortic valve complicated by severe aortic regurgitation

Introduction Infective endocarditis (IE) in young individuals is uncommon but may occur in the presence of congenital heart disease. Congenital bicuspid aortic valve is recognized as a predisposing lesion in the 2023 ESC guideline on IE. Abiotrophia defectiva, a nutritionally variant streptococcus, is rare yet highly aggressive and associated with adverse outcomes.Case Presentation A 19-year-old boy with no prior comorbidity admitted with one month history of lethargy and a brief febrile episode which resolved spontaneously. Notably, he had undergone dental extraction two weeks prior to fever onset. Two days prior to admission, he developed fingernail swelling. Examination revealed finger clubbing and a diastolic murmur at the aortic area. He was haemodynamically stable. Investigations showed normocytic anemia, leucocytosis and elevated C-reactive protein. Echocardiography demonstrated a bicuspid aortic valve with large vegetation and severe aortic regurgitation.Results Blood cultures yielded Abiotrophia defectiva Intravenous ceftriaxone was initiated. CT thorax, abdomen and pelvis showed no evidence of metastatic infection. Due to the severe aortic regurgitation, he underwent urgent prosthetic aortic valve replacement. Post-operatively, he was maintained on warfarin and completed six weeks of intravenous ceftriaxone in accordance with IE treatment guidelines. Inflammatory markers normalized and repeat cultures were sterile.Discussion Abiotrophia defectiva accounts for