Subacute Infective Endocarditis due to Aerococcus Urinae in a 16-Year-Old Boy with no Pre-existing Cardiac Anomaly

Aerococcus urinae is a pathogen that causes urinary tract infections and a rare cause of infective endocarditis in the elderly population. To date, only 2 case reports of Aerococcus urinae infective endocarditis in children have been published, both of which had a predisposing congenital heart defect.

We present a 16-year-old boy with Trisomy 21 and no existing cardiac anomaly, as per echocardiography during childhood, which was normal. He presented with prolonged fever of 2.5 months intermittently, and pain in his left knee.

He was treated in the community with several antibiotic regimens for suspected pneumonia and tonsillitis. Upon presentation to the emergency room, his physical examination revealed a new 3/6 blowing holosystolic murmur, best heard at the apex and radiating to the axilla and to the back. Laboratory workup showed microcytic anemia (HB-11.4 g/dl), thrombocytopenia (PLT – 79K), increased levels of inflammation markers (CRP- 70 mg/L), and blood culture showed growth of Aerococcus urinae. On echocardiogram a mitral valve vegetation and moderate MR were noted. He was treated with ampicillin G + gentamycin for infective endocarditis and referred to a tertiary hospital for surgical excision of the vegetation and mitral valve repair. The operation was successful, and the patient continued intravenous antibiotic therapy with ampicillin G for 6 weeks and gentamycin for 3 weeks for synergy. In echo one year after surgery, only mild MR was demonstrated.

To the best of our knowledge this is the first report of Aerococcus urinae infective endocarditis in a child with no pre-existing cardiac anomaly.