[Brucella canis endocarditis: first documented case in Argentina].

We herein present the case of an adult male patient who consulted for lower extremity edema, a 2- month history of fever and oppressive chest pain radiating to the left arm. He referred neither contact with breeding animals nor consumption of unpasteurized dairy products. A diagnosis of endocarditis was confirmed by cardiac studies. Since the empirical treatment with cephalotin, ampicillin and gentamicin failed, the patient underwent aortic valve replacement. A total of four blood cultures were positive with a gram-negative rod. Bacterial identification was performed using the API 20 NE technique (bioMèrieux), the Phoenix automated method (BD) and conventional biochemical tests which were unable to classify the isolate as to genus and species. The strain was sent to the INEI-ANLIS "Dr. Carlos G. Malbrán" where it was identified as Brucella canis. The antimicrobial treatment was switched to doxycycline, rifampicin and trimethoprim-sulfamethoxazole with good evolution of the patient. The clinical significance of this case report lies in the possible failure of the empiric antibiotic therapy administered for endocarditis, since B. canis did not respond to the conventional antimicrobial treatment for this pathology.