Impact of drug resistance on fitness of Mycobacterium tuberculosis strains of the W-Beijing genotype

• Published in: FEMS immunology and medical microbiology Vol. 42; no. 3; pp. 281 - 290
• Main Authors: Toungoussova, Olga S., Caugant, Dominique A., Sandven, Per, Mariandyshev, Andrey O., Bjune, Gunnar
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier B.V 01-11-2004; Blackwell Publishing Ltd
• Subjects: Antitubercular Agents - pharmacology; DNA Transposable Elements; DNA-Directed RNA Polymerases - genetics; Drug Resistance, Bacterial - genetics; Fitness; Genotype; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Mycobacterium tuberculosis - drug effects; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - growth & development; Mycobacterium tuberculosis - isolation & purification; Reproducibility of Results; Tuberculosis - microbiology; W-Beijing family; Mycobacterium tuberculosis; W-Beijing family; Fitness
• ISSN: 0928-8244; 1574-695X
• DOI: 10.1016/j.femsim.2004.05.012

Mycobacterium tuberculosis strains of the W-Beijing genotype became a common cause of tuberculosis during the past years and they are often associated with drug resistance. The biological factors facilitating the selection and wide dissemination of these strains are not known. To determine how acquisition of drug resistance affected growth of strains of the W-Beijing genotype, the growth of 55
M. tuberculosis isolates were studied using the BBL MGIT
Mycobacteria Growth Indicator Tube and the BACTEC MGIT 960 System. Susceptible strains of non-Beijing genotypes were found to be the most fit strains. Drug-resistant strains of non-Beijing genotypes were more likely to grow slower than susceptible strains (
P=0.001). Drug-resistant strains of the W-Beijing genotype had two tendencies of growth: some of them showed reduced growth compared to susceptible strains, while others did not show loss of fitness measured as growth.