Aortic valve endocarditis in a dog due to Bartonella clarridgeiae

We report the first documented case of endocarditis associated with Bartone lla clarridgeiae in any species. B. clarridgeiae was identified as a possib le etiological agent of human cat scratch disease. Infective vegetative val vular aortic endocarditis was diagnosed in a 2.5-year-old male neutered box er. Historically, the dog had been diagnosed with a systolic murmur at 16 m onths of age and underwent balloon valvuloplasty for severe valvular aortic stenosis. Six months later, the dog was brought to a veterinary hospital w ith an acute third-degree atrioventricular block and was diagnosed with inf ective endocarditis. The dog died of cardiopulmonary arrest prior to pacema ker implantation. Necropsy confirmed severe aortic vegetative endocarditis. Blood culture grew a fastidious, gram-negative organism 8 days after being plated. Phenotypic and genotypic characterization of the isolate, includin g partial sequencing of the citrate synthase (gltA) and 16S rRNA genes indi cated that this organism was B. clarridgeiae. DNA extraction from the defor med aortic valve and the healthy pulmonic valve revealed the presence of B. clarridgeiae DNA only from the diseased valve. No Borrelia burgdorferi or Ehrlichia sp. DNA could be identified. Using indirect immunofluorescence te sts, the dog was seropositive for B. clarridgeiae and had antibodies agains t Ehrlichia phagocytophila but not against Ehrlichia canis, Ehrlichia ewing ii, B. burgdorferi, or Coxiella burnetti.