Epidemiologic and Clinical Characteristics of Bartonella quintana and Bartonella henselae Endocarditis : A Study of 48 Patients

Although cat scratch disease is commonly diagnosed in patients who have unexplained regional lymphadenopathy after encounters with cats, its epidemiology and the risk factors for disease are not clearly defined, and there is no generally accepted diagnostic test. We conducted a physician survey to identify cases of cat scratch disease occurring over a 13-month period in cat owners in Connecticut. We interviewed both the patients (or their parents) and controls matched for age who owned cats. Serum from the patients was tested for antibodies to Rochalimaea henselae with a new, indirect fluorescent-antibody test. We identified 60 patients with cat scratch disease and 56 age-matched subjects. Patients were more likely than controls to have at least one pet kitten 12 months old or younger (odds ratio, 15), to have been scratched or bitten by a kitten (odds ratio, 27), and to have had at least one kitten with fleas (odds ratio, 29). A conditional logistic-regression analysis found that in kitten-owning households, patients were more likely than controls to have been scratched or bitten by a cat or kitten (odds ratio, 12.4; 95 percent confidence interval, 1.0 to 150). Of 45 patients, 38 had serum samples with titers of 1:64 or higher for antibody to R. henselae, as compared with 4 of 112 samples from controls (P < 0.001). The positive predictive value of the serologic test was 91 percent. Of 48 serum samples from patients' cats, 39 were positive for antibodies to R. henselae, as compared with positive samples from 11 of 29 control cats (P < 0.001). Cat scratch disease is strongly associated with owning a kitten, and fleas may be involved in its transmission. The serologic test for rochalimaea may be useful diagnostically, and our results suggest an etiologic role for this genus.

Bartonella species are emerging pathogens that are seldom reported as a cause of blood culture-negative endocarditis. To report the occurrence of, risk factors for, and clinical features of Bartonella endocarditis and to evaluate the diagnostic tools available for this condition. Case series and comparison with past series. Multicenter international study in Halifax, Nova Scotia, Canada; Lyon, France; and Marseille, France. 22 patients from France, England, Canada, and South Africa were investigated for blood culture-negative endocarditis. Titer of antibodies to Bartonella species by microimmunofluorescence assay, blood or vegetation culture, and amplification of Bartonella DNA from valvular tissue by polymerase chain reaction. Cross-adsorption was done for patients with antibodies to Chlamydia species. 22 patients had definite endocarditis. Five were infected with B. quintana, 4 with B. henselae, and 13 with an undetermined Bartonella species. These cases were compared with the 11 previously reported cases. Of the patients with the newly reported cases, 19 had valvular surgery and 6 died. Nine were homeless, 11 were alcoholic, 4 owned cats, and 13 had preexisting valvular heart disease. Bartonella species caused 3% of the cases of endocarditis 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 Chlamydia species. Bartonella species are an important cause of blood culture-negative endocarditis and can be identified by culture, 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.