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Stability of Mycobacterium tuberculosis DNA genotypes
R W Yeh1, A Ponce de Leon, C B Agasino
1Department of Medicine, Stanford University School of Medicine, CA 94305, USA.
The Journal of Infectious Diseases
|April 16, 1998
Summary
Mycobacterium tuberculosis DNA genotypes showed instability in 29% of patients over time. This genetic plasticity, particularly with IS6110 markers, offers insights into tuberculosis evolution and transmission dynamics.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Mycobacterium tuberculosis genotype stability is crucial for molecular epidemiology.
- Understanding genetic variation aids in tracking disease transmission and evolution.
Purpose of the Study:
- To evaluate the stability of Mycobacterium tuberculosis DNA genotypes in sequential patient isolates.
- To investigate the implications of observed genotype changes for molecular epidemiology and disease transmission.
Main Methods:
- Comparison of DNA genotypes using IS6110 and polymorphic GC-rich sequence (PGRS) markers.
- Analysis of sequential sputum isolates from 49 patients with M. tuberculosis, separated by at least 90 days.
Main Results:
- Genotype changes were observed in 14 (29%) of 49 patients.
- IS6110 genotype changes occurred in 12 patients, primarily in strains with 8-14 bands.
- No correlation found between genotype changes and drug susceptibility, HIV status, or therapy adherence.
Conclusions:
- Significant Mycobacterium tuberculosis genotype instability exists, complicating molecular epidemiology.
- IS6110 genotype changes may reflect genetic plasticity, offering insights into M. tuberculosis evolution and virulence.
- Observed genetic changes can be leveraged to enhance understanding of disease transmission patterns.