Drug Susceptibility of Mycobacterium tuberculosis Beijing Genotype and Association with MDR TB
Jurriaan E.M. de Steenwinkel , Marian T. ten Kate, Gerjo J. de Knegt, Kristin Kremer, Rob E. Aarnoutse, Martin J. Boeree, Henri A. Verbrugh, Dick van Soolingen, and Irma A.J.M. Bakker-Woudenberg
Author affiliations: Erasmus University Medical Center, Rotterdam, the Netherlands (J.E.M. de Steenwinkel, M.T. ten Kate, G.J. de Knegt, H.A. Verbrugh, I.A.J.M. Bakker-Woudenberg); National Institute of Public Health and the Environment Center for Infectious Disease Control (RIVM),; Bilthoven, the Netherlands (K. Kremer, D. van Soolingen); World Health Organization Regional Office for Europe, Copenhagen, Denmark (K. Kremer); Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands (R.E. Aarnoutse, M.J. Boeree, D. van Soolingen)
Figure 2. Concentration- and time-dependent bactericidal effect of rifampin (RIF) toward low-density cultures of Mycobacterium tuberculosis BE-1585 (5.1 × 105 CFU/mL) (A) and M. tuberculosis EAI-1627 (6.8 × 105 CFU/mL) (B). Cultures were exposed to RIF at 2-fold increasing concentrations for 6 days at 37°C. After 1, 3, or 6 days of exposure, subcultures were performed on solid media to count CFUs. *Accurate CFU counting could not be performed because complete outgrowth of mycobacteria occurred on the sixth day of RIF exposure, leading to aggregation.
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