Outcome and treatment of Bartonella endocarditis

Background: Endocarditis caused by Bartonella species is a potentially lethal infection characterized by a subacute evolution and severe valvular lesions. Objectives: To evaluate the outcome of patients with Bartonella endocarditis and to define the best antibiotic regimen using the following measures: recovery, relapse, or death. Methods: We performed a retrospective study on 101 patients who were diagnosed in our laboratory as having Bartonella endocarditis between January 1, 1995, and April 30, 2001. Bartonella infection was diagnosed using immunofluorescence with a 1:800 cutoff, polymerase chain reaction amplification of DNA, and/or culture findings of Bartonella species from whole blood, serum, and/or valvular biopsy specimens. A standardized questionnaire was completed by investigators for each patient. Results: Twelve of the 101 patients died and 2 relapsed. Patients receiving an aminoglycoside were more likely to fully recover (P=.02), and those treated with aminoglycosides for at least 14 days were more likely to survive than those with shorter therapy duration (P=.02). Conclusion: Effective antibiotic therapy for Bartonella endocarditis should include an aminoglycoside prescribed for a minimum of 2 weeks.