A study on forensic samples of Bartonella spp antibodies in Swedish intravenous heroin addicts

Infection with Bartonella, an emerging bacterial pathogen which often affects immunodeficient patients, has been reported in Sweden over the past few years, with a high seroprevalence of B. elizabethae. A high prevalence of antibodies against B. elizabethae has also been found in urban intravenous drug users in the USA. Using immunofluorescence, we retrospectively examined serum samples taken at autopsy from 59 Swedish intravenous drug addicts from the Stockholm area for evidence of antibodies against 6 pathogenic strains of Bartonella. The 59 addicts died following heroin injection during the years 1987-1992 and include 24 individuals (41%) who were additionally HIV-positive. An overall seropositivity rate for Bartonella spp. of 39% (23/59) was found with the following antigenic reactivities: B. elizabethae, 39% (23/59); B. grahamii, 3% (2/59); B. henselae (Houston-1), 14% (8/59); and B. quintana, 3% (2/59). There were no positive reactions for B. henselae (Marseille) or B. vinsonii subsp. vinsonii. The Bartonella-seropositive cases included 11/23 (48%) individuals who were HIV-positive. Subacute to chronic myocarditis was seen in 2/11 microscopically investigated Bartonella-seropositive cases that were HIV-negative and in 1/14 seronegative cases. No cases of endocarditis or other common manifestations of Bartonella infection were found. An overall Bartonella seropositivity of 21% (9/44) was observed in control forensic autopsy samples.