Mycobacterium tuberculosis bacteremia in HIV-negative patients

Limited information exists about the epidemiologic characteristics of HIV-negative patients with Mycobacterium tuberculosis bacteremia (MTB).

We retrospectively surveyed tuberculosis (TB) cases reported at National Taiwan University Hospital between 1997 and 2003. Demographic data, underlying diseases or conditions, clinical, microbiologic and radiologic findings and therapy were collected. Long-term outcome was evaluated at 1 year after initiation of anti-TB agents.

During the study period the incidence of MTB bacteremia in HIV-negative patients and HIV-positive patients were 0.024 and 6.2 per 1000 discharges, respectively (p<0.01). All 11 HIV-negative patients were males and eight (73%) were more than 50 years old. The most common underlying diseases/conditions were immunosuppressive therapy (64%) and heart disease (55%). Fever (80%), lymphopenia (75%) and pulmonary symptoms (58%) were the most common presentations. Ten patients were septic, two had septic shock and two had acute respiratory distress syndrome on admission. The median interval between admission and initiation of therapy for those who were cured was 6 days. Six (55%) died of TB and/or their underlying diseases. Of the six patients who died, the median survival after collection of positive blood culture was 19 days for three treated patients and 7 days for three untreated patients (p=0.01).

This case series demonstrates the wide spectrum of the initial presentation of HIV-negative patients with MTB bacteremia. The case fatality rate was high and was likely due to immunocompromised status and no anti-TB treatment prior to death. A high index of suspicion for TB and blood culture for MTB provides an additional simple and noninvasive diagnostic method to detect disseminated TB in endemic areas.