Duke criteria-negative endocarditis caused by Bartonella quintana.

Bartonella spp. were recently recognized as causative agents of culture-negative endocarditis. Molecular techniques, such as broad-range PCR, are now available to detect fastidious or slow-growing microorganisms, or those which cannot be cultured. Such microorganisms may be responsible for culture-negative endocarditis. Alcoholism and homelessness are known risk factors for Bartonella quintana endocarditis, even in patients without previous valvular disease. We report a case of B. quintana endocarditis diagnosed by PCR amplification on the excised heart valve, in a young non-alcoholic and immunocompetent patient with few clinical signs of infection who did not fulfill the Duke criteria.