Multiple Blood Cultures Required to Detect M. tuberculosis Bacteremia in HIV-Positive Patients
In two South African cohorts of HIV-infected inpatients, a single blood culture missed 27% of M. tuberculosis bloodstream infections that were detected by a second culture. In a prospective arm with up to 6 cultures, 35% of cases required more than one blood culture for diagnosis. These findings demonstrate that TB bacteremia is significantly underdiagnosed by standard single-culture practice in high-HIV-burden settings.
The original study
HIV-Associated Mycobacterium tuberculosis Bloodstream Infection Is Underdiagnosed by Single Blood Culture.
- Authors
- Barr DA, Kerkhoff AD, Schutz C, Ward AM, Davies GR, Wilkinson RJ, et al.
- Journal
- Journal of clinical microbiology
- Type
- Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't
- PMID
- 29444831
Original abstract
We assessed the additional diagnostic yield for Mycobacterium tuberculosis bloodstream infection (BSI) by doing more than one tuberculosis (TB) blood culture from HIV-infected inpatients. In a retrospective analysis of two cohorts based in Cape Town, South Africa, 72/99 (73%) patients with M. tuberculosis BSI were identified by the first of two blood cultures during the same admission, with 27/99 (27%; 95% confidence interval [CI], 18 to 36%) testing negative on the first culture but positive on the second. In a prospective evaluation of up to 6 blood cultures over 24 h, 9 of 14 (65%) patients with M. tuberculosis BSI had M. tuberculosis grow on their first blood culture; 3 more patients (21%) were identified by a second independent blood culture at the same time point, and the remaining 2 were diagnosed only on the 4th and 6th blood cultures. Additional blood cultures increase the yield for M. tuberculosis BSI, similar to what is reported for nonmycobacterial BSI.