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Restriction fragment length polymorphism analysis of Mycobacterium avium isolates from animal and human sources
D O'Grady1, O Flynn, E Costello
1Central Veterinary Research Laboratory, Abbotstown, Castleknock, Ireland. eamoncos@indigo.ie
Abstract:
Restriction fragment length polymorphism (RFLP) analysis using probes derived from the insertion sequences IS901, IS1245 and IS1311, was carried out on Mycobacterium avium isolates obtained from 18 human patients, 44 deer, 14 pigs and five cattle in the Republic of Ireland. Forty-two of the cervine isolates and two of the bovine isolates contained IS901, while this insertion sequence was absent from all of the human and porcine isolates. RFLP analysis with IS901 probe differentiated the 44 field isolates which contained this element into three types. All of the IS901-positive isolates had a characteristic three-band IS1245 hybridisation pattern and a characteristic single-band IS1311 hybridisation pattern. The IS901-negative isolates exhibited highly polymorphic IS1245 and IS1311 hybridisation patterns which differentiated the human and porcine isolates into a wide diversity of strain types.
Insights
Restriction fragment length polymorphism (RFLP) analysis revealed distinct Mycobacterium avium strains. IS901 insertion sequences were found in deer and cattle, but not humans or pigs, differentiating these animal reservoirs.
Area of Science:
- Microbiology
- Genetics
- Veterinary Science
Background:
- Mycobacterium avium is a significant pathogen with diverse host ranges.
- Understanding the genetic diversity of M. avium is crucial for disease control and epidemiology.
- Insertion sequences (IS) are mobile genetic elements that can contribute to genomic variation.
Purpose of the Study:
- To investigate the genetic diversity of Mycobacterium avium isolates from various hosts in Ireland.
- To determine the presence and distribution of insertion sequences IS901, IS1245, and IS1311 in these isolates.
- To differentiate M. avium strains based on RFLP patterns.
Main Methods:
- Restriction fragment length polymorphism (RFLP) analysis was performed.
- Probes derived from insertion sequences IS901, IS1245, and IS1311 were used for hybridisation.
- Isolates were sourced from human patients, deer, pigs, and cattle in the Republic of Ireland.
Main Results:
- IS901 was detected in 42 deer and 2 cattle isolates, but absent in all human and porcine isolates.
- RFLP with the IS901 probe identified three distinct types among the IS901-positive field isolates.
- IS901-positive isolates shared common IS1245 and IS1311 hybridisation patterns.
- IS901-negative isolates (human and porcine) showed highly polymorphic IS1245 and IS1311 patterns, indicating significant strain diversity.
Conclusions:
- The presence of IS901 insertion sequences can differentiate Mycobacterium avium isolates from cervine and bovine sources from those of human and porcine origins.
- RFLP analysis using IS901, IS1245, and IS1311 probes is effective in characterising M. avium strain diversity.
- Distinct genetic profiles suggest potential host-specific adaptations or transmission routes for Mycobacterium avium.