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

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Endocarditis is a serious cardiac infection often requiring prompt antibiotic treatment.
• Empirical antibiotic therapy is common for suspected endocarditis, guided by likely pathogens.

Observation:

• An adult male presented with symptoms suggestive of endocarditis, including fever and chest pain.
• Initial blood cultures were positive for a gram-negative rod resistant to empirical antibiotics (cephalotin, ampicillin, gentamicin).
• Despite aortic valve replacement, the pathogen remained unidentified by standard methods.

Findings:

• Advanced identification techniques confirmed the isolate as Brucella canis.
• Brucella canis infection demonstrated resistance to the initial empirical antibiotic regimen.
• Treatment was successfully switched to doxycycline, rifampicin, and trimethoprim-sulfamethoxazole, leading to patient improvement.

Implications:

• This case underscores the potential inadequacy of empirical antibiotic therapy for Brucella canis endocarditis.
• Accurate and timely identification of Brucella species is crucial for effective treatment of endocarditis.
• Highlights the importance of considering zoonotic infections like Brucella canis in endocarditis cases, even without typical exposure history.