Fitness of Mycobacterium tuberculosis strains of the W-Beijing and Non-W-Beijing genotype.

• Main Authors: Andrea von Groll, Anandi Martin, Matthias Stehr, Mahavir Singh, Françoise Portaels, Pedro Eduardo Almeida da Silva, Juan Carlos Palomino
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2010-01-01
• Series: PLoS ONE
• Online Access: http://europepmc.org/articles/PMC2855714?pdf=render

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 80. Further studies are needed to elucidate the putative advantage of W-Beijing strains compared to other genotypes.