A whole blood bactericidal assay for tuberculosis
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Updated: Oct 9, 2026

A Functional Whole Blood Assay to Measure Viability of Mycobacteria, using Reporter-Gene Tagged BCG or M.Tb (BCG lux/M.Tb lux)
Published on: September 14, 2011
R S Wallis1, M Palaci, S Vinhas
1University of Medicine and Dentistry-New Jersey Medical School, 185 S. Orange Ave., MSB I-503, Newark, NJ 07103, USA. wallisrs@umdnj.edu
Abstract:
The bactericidal activity of orally administered antituberculosis (anti-TB) drugs was determined in a whole blood culture model of intracellular infection in which microbial killing reflects the combined effects of drug and immune mechanisms. Rifampin (Rif) was the most active compound studied and reduced the number of viable bacilli by >4 logs. Isoniazid (INH), 2 quinolones, and pyrazinamide (PZA) showed intermediate levels of activity. Ethambutol exerted only a bacteristatic effect; amoxicillin/clavulanate was inactive. The combination of INH-Rif-PZA showed strong activity against 11 drug-sensitive isolates (mean, -3.8 log) but no activity against 12 multidrug-resistant (MDR) strains. The combination of levofloxacin-PZA-ethambutol had intermediate bactericidal activity against MDR isolates (mean, -1.2 log) but failed to equal that of INH-Rif-PZA against sensitive isolates (P<.001). The whole blood BACTEC method (Becton Dickinson) may be useful for the early clinical evaluation of new anti-TB drugs and in the management of individual patients.

