BARTONELLA (ROCHALIMAEA) QUINTANA ENDOCARDITIS IN 3 HOMELESS MEN

Background. Bartonella (Rochalimaea) quintana is the agent of trench f ever and is transmitted by the body louse, We-searched for this organi sm in three alcoholic homeless men with endocarditis. Methods. Blood s amples were cultured on a human endothelial cell line and on blood aga r. Bacteria were identified by sequencing the amplified 16S ribosomal RNA gene. The presence of bartonella in tissue was assessed by Gram's staining, immunostaining, and polymerase-chain-reaction amplification. Serologic studies for antibodies to bartonella species were performed by indirect immunofluorescence and Western immunoblotting. Results. B . quintana was isolated from one patient in the blood-agar culture and from the other two patients in the endothelial-cell culture. The orga nism was also identified by both immunostaining and molecular techniqu es in the valvular vegetations from the three patients and in a cervic al lymph node from one patient. The 16S ribosomal RNA gene sequences o f the three isolates were almost identical to that of the prototype st rain of B. quintana. High titers of antibodies to B. quintana were det ected in all three patients, but so were cross-reacting antibodies to chlamydia species. In all three patients studies were repeatedly negat ive for antibodies to the human immunodeficiency virus. Conclusions. B . quintana is a cause of endocarditis in homeless patients and may be serologically misdiagnosed as a chlamydial infection.