Bacteremia due to Mycobacterium tuberculosis or M. bovis, Bacille Calmette–Guérin (BCG) among HIV-positive children and adults in Zambia

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Abstract
Background Among adults with advanced HIV infection in developing countries, bacteremia due to Mycobacterium tuberculosis (MTB) is common and bacteremia due to M. bovis (bacille Calmette–Guérin; BCG) is rare. Comparable data are not available for children with HIV. Objective To compare the prevalence of bacteremia due to M. tuberculosis or M. bovis BCG in hospitalized children and adults with HIV infection in a developing country with a high prevalence of tuberculosis and HIV and > 95% BCG immunization coverage. Design Descriptive cross-sectional study. Methods Prospectively hospitalized patients in Lusaka, Zambia who were suspected to have HIV infection underwent phlebotomy for HIV ELISA, HIV viral load, and lysis-centrifugation blood culture for mycobacteria. Histories were obtained and patients were examined for BCG scars. Mycobacterial isolates were identified using DNA probes for MTB complex (MTBC), multiplex PCR and IS 6110 typing. Results The median age of 387 HIV-positive children was 15 months; 98% were BCG immunized. The median age of 344 HIV-positive adults was 32 years; 44% were BCG immunized. Blood cultures were positive for mycobacteria in six children (2%) and 38 adults(11%) (P < 0.001). The six pediatric isolates included five MTBC (40% clustered) and one BCG. The 38 adult isolates included 36 MTBC (16% clustered) and two M. avium complex. Conclusion Bacteremia due to MTB is less common among children than adults with advanced HIV infection in Zambia. Bacteremia due to M. bovis BCG is rare even among children with recent BCG immunization and symptomatic HIV infection.