Chronic Bartonella quintana bacteremia in homeless patients

Background Infection with Bartonella quintana can cause french fever, endoc arditis, bacillary angiomatosis, and peliosis. An outbreak of bacteremia du e to B. quintana has been reported among homeless people in Seattle, and th e seroprevalence is high among homeless people in both the United States an d Europe. Body lice are known to be the vectors of B. quintana. Methods We studied all the homeless people who presented in 1997 to the eme rgency departments of the University Hospital, Marseiiles, France. Blood wa s collected for microimmunofluorescence testing for antibodies against B. q uintana and for culture of the bacterium. Body lice were collected and anal yzed by the polymerase chain reaction and sequencing of a portion of the ci trate synthase gene of B. quintana. Results in 10 of 71 homeless patients (14 percent), blood cultures were pos itive for B. quintana, and 21 of the patients (30 percent) had high titers of antibody against the organism. A total of 17 patients (24 percent) had e vidence of recent infection (bacteremia or seroconversion). Tests of lice f rom 3 of the 15 patients from whom they were collected were positive for B. quintana. The homeless people with B. quintana bacteremia were more likely to have been exposed to lice (P=0.002), were more likely to have headaches (P=0.03) and severe leg pain (P<0.001), and had lower platelet counts (P=0 .006) than the homeless people who were seronegative for B. quintana and di d not have bacteremia; 8 of the 10 patients with bacteremia were afebrile. Five patients had chronic bacteremia, as indicated by positive blood cultur es over a period of several weeks. Conclusions in an outbreak of urban trench fever among homeless people in M arseiiles, B. quintana infections were associated with body lice in patient s with nonspecific symptoms or no symptoms. (N Engl J Med 1999;340:184-9.) (C) 1999, Massachusetts Medical Society.