DIAGNOSIS OF 22 NEW CASES OF BARTONELLA-ENDOCARDITIS

Background: Bartonella species are emerging pathogens that are seldom reported as a cause of blood culture-negative endocarditis. Objective: To report the occurrence of, risk factors for, and clinical features of Bartonella endocarditis and to evaluate the diagnostic tools availa ble for this condition. Design: Case series and comparison with past s eries. Setting: Multicenter international study in Halifax, Nova Scoti a, Canada; Lyon, France; and Marseille, France. Patients: 22 patients from France, England, Canada, and South Africa were investigated for b lood culture-negative endocarditis. Measurements: Titer of antibodies to Bartonella species by microimmunofluorescence assay, blood or veget ation culture, and amplification of Bartonella DNA from valvular tissu e by polymerase chain reaction. Cross-adsorption was done for patients with antibodies to Chlamydia species. Results: 22 patients had defini te endocarditis. Five were infected with B. quintana, 4 with B. hensel ae, and 13 with an undetermined Bartonella species. These cases were c ompared with the 11 previously reported cases. Of the patients with th e newly reported cases, 19 had valvular surgery and 6 died. Nine were homeless, 11 were alcoholic, 4 owned cats, and 13 had preexisting valv ular heart disease. Bartonella species caused 3% of the cases of endoc arditis seen in the three study centers. The patients with these cases could have previously received a diagnosis of chlamydial endocarditis because of apparently high levels of cross-reacting antibodies to Chl amydia species. Conclusions: Bartonella species are an important cause of blood culture-negative endocarditis and can be identified by cultu re, serologic studies, or molecular biology techniques. Alcoholism and homelessness without previous valvular heart disease are risk factors for B. quintana infection but not for infection with other Bartonella species.