fitness of mycobacterium tuberculosis strains of the w-beijing and non-w-beijing genotype健身的结核分枝杆菌菌株w-beijing non-w-beijing基因型.pdfVIP

Fitness of Mycobacterium tuberculosis Strains of the W-Beijing and Non-W-Beijing Genotype 1 1 2 2 1 Andrea von Groll *, Anandi Martin , Matthias Stehr , Mahavir Singh , Franc¸oise Portaels , Pedro Eduardo Almeida da Silva3, Juan Carlos Palomino1 1 Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium, 2 Department of Genome Analysis, Helmholtz Centre for Infection Research, Braunswcheig, Germany, 3 Laboratory of Mycobacteriology, Universidade Federal do Rio Grande, Rio Grande, Brazil Abstract Background: Multidrug resistant tuberculosis (MDR-TB) is a major threat for global tuberculosis control. The W-Beijing Mycobacterium tuberculosis genotype has been associated with drug resistance. Elucidation of the mechanisms underlying this epidemiological finding may have an important role in the control of MDR-TB. The aim of this study was to evaluate the fitness of drug-susceptible and MDR M. tuberculosis strains of the W-Beijing genotype compared with that of Non-W-Beijing strains. Methodology/Principal Findings: Fitness of M. tuberculosis strains was determined by evaluating the difference in the growth curves obtained in the MGIT960 automated system and assessing the competitive growth capacity between W- Beijing and non-W-Beijing strains. The W-Beijing MDR strains had a significant longer lag phase duration compared to the other strains but did not present a significant fitness cost. When grown in competition they had an advantage only in medium containing 0.1% Tween 80. Conclusions/Significance: It was not possible to confirm a selective advantage of W-Beijing strains to grow, except for differences in their resistance to Tween 8