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Genetic diversity among Mycobacterium avium complex AccuProbe-positive isolates
H Soini1, E Eerola, M K Viljanen
1Department in Turku, National Public Health Institute, Turku, Finland.
Journal of Clinical Microbiology
|January 1, 1996
Summary
Genetic analysis of Mycobacterium avium complex (MAC) isolates revealed significant diversity. Some strains showed novel sequences, suggesting MAC may encompass more species than currently recognized.
Area of Science:
- Microbiology
- Genetics
- Mycobacterial Research
Background:
- The Mycobacterium avium complex (MAC) is a group of closely related mycobacteria.
- Accurate identification of MAC species is crucial for clinical management and epidemiological studies.
Purpose of the Study:
- To investigate the genetic diversity within MAC clinical isolates identified solely by the AccuProbe MAC test.
- To determine if these isolates represent known MAC species or novel genetic variants.
Main Methods:
- Partial 32-kDa-protein gene sequencing was performed on 22 MAC clinical isolates.
- Nucleotide sequences were compared to reference sequences of Mycobacterium tuberculosis, M. avium, and M. intracellulare using sequence analysis software.
Main Results:
- A wide range of genetic diversity was observed among the studied MAC strains.
- Sixteen isolates exhibited sequences similar to, but not identical to, M. avium and M. intracellulare, consistent with true MAC strains.
- Five isolates possessed novel MAIX sequences, significantly different from other analyzed mycobacteria.
- One isolate displayed sequences greatly divergent from all reference strains.
Conclusions:
- The findings support the hypothesis that the MAC comprises several additional, yet uncharacterized, species.
- The study suggests that the MAC AccuProbe may cross-react with certain mycobacterial strains not belonging to the MAC, potentially impacting diagnostic accuracy.