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Volume 18, Number 4—April 2012


Drug Susceptibility of Mycobacterium tuberculosis Beijing Genotype and Association with MDR TB

Jurriaan E.M. de SteenwinkelComments to Author , 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)

Main Article

Table 2

Concentration- and time-dependent bactericidal effect of rifampin toward Mycobacterium tuberculosis genotypes in low- and high-density cultures*

Day Lowest RIF concentration resulting in killing of M. tuberculosis, mg/L
Beijing-1585 genotype
EAI-1627 genotype
>99% killing
100% killing
>99% killing
100% killing
Low† High‡ Low† High‡ Low§ High¶ Low§ High¶
1 8 ND 256 ND 8 ND 32 ND
3 1 0.008 64 1024 0.125 0.03 8 32
6 0.001 0.008 2 64 0.001 0.06 1 2

*Cultures were exposed to RIF at 2-fold increasing concentrations for 6 days at 37°C; at indicated time-points, subcultures were performed on solid media for counting. Low, low-density culture; high, high-density culture; ND, not determined.
†Density of 5.1 × 105 CFU/mL.
‡Density of 4.4 × 106 CFU/mL.
§Density of 6.8 × 105 CFU/mL.
¶Density of 3.0 × 106 CFU/mL.

Main Article