Mycobacterium tuberculosis bacteremia in a university hospital.

ABSTRACT

SETTING: Patients with blood cultures positive for Mycobacterium tuberculosis between 1988 and 1999. OBJECTIVE: To study the clinical and microbiological characteristics of patients with tuberculous bacteremia, including data about evolution and management. DESIGN: Retrospective review of the clinical charts and microbiological records of patients with culture-proven tuberculous bacteremia between 1988-1999. RESULTS: During the study period, 19 patients with culture-proven M. tuberculosis bacteremia were detected (1.42 isolates/patient, 4.7% of all patients with blood cultures for mycobacteria). Four patients were non-infected with the human immunodeficiency virus and 15 were HIV-infected. In four patients blood was the only positive sample. Five patients were diagnosed simultaneously with tuberculosis and HIV infection. Only 13 had a temperature higher than 37.5 degrees C. Most patients had symptoms or signs of respiratory tract involvement, and 11 patients died (10 from tuberculosis). The average time for detection of positive blood cultures was 33.25 days for lysis-centrifugation cultures and 26.46 days for BACTEC cultures. The incidence of M. tuberculosis bacteremia remained stable during the study period. CONCLUSIONS: Although blood cultures are useful for definitive diagnosis of disseminated tuberculosis, the long incubation times made them of limited usefulness in the clinical management of patients. Mortality remains high in these patients.