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DNA Fingerprinting of Mycobacterium leprae Strains Using Variable Number Tandem Repeat VNTR - Fragment Length Analysis FLA
Published on: July 15, 2011
Detection of Mycobacterium leprae DNA in soil: multiple needles in the haystack
Maria Tió-Coma1, Thomas Wijnands1, Louise Pierneef1
1Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
Abstract:
Leprosy is an infectious disease caused by Mycobacterium leprae affecting the skin and nerves. Despite decades of availability of adequate treatment, transmission is unabated and transmission routes are not completely understood. Despite the general assumption that untreated M. leprae infected humans represent the major source of transmission, scarce reports indicate that environmental sources could also play a role as a reservoir. We investigated whether M. leprae DNA is present in soil of regions where leprosy is endemic or areas with possible animal reservoirs (armadillos and red squirrels). Soil samples (n = 73) were collected in Bangladesh, Suriname and the British Isles. Presence of M. leprae DNA was determined by RLEP PCR and genotypes were further identified by Sanger sequencing. M. leprae DNA was identified in 16.0% of soil from houses of leprosy patients (Bangladesh), in 10.7% from armadillos' holes (Suriname) and in 5% from the habitat of lepromatous red squirrels (British Isles). Genotype 1 was found in Bangladesh whilst in Suriname the genotype was 1 or 2. M. leprae DNA can be detected in soil near human and animal sources, suggesting that environmental sources represent (temporary) reservoirs for M. leprae.
Insights
Leprosy transmission routes remain unclear, but Mycobacterium leprae DNA was found in soil near human and animal cases. This suggests environmental soil may act as a temporary reservoir for leprosy bacteria.
Area of Science:
- Microbiology
- Infectious Diseases
- Environmental Science
Background:
- Leprosy, caused by Mycobacterium leprae, affects skin and nerves.
- Despite available treatment, leprosy transmission persists, with routes not fully understood.
- While humans are assumed to be the primary source, environmental reservoirs are suspected.
Purpose of the Study:
- To investigate the presence of Mycobacterium leprae DNA in soil from endemic regions.
- To explore potential environmental reservoirs for M. leprae transmission.
- To identify M. leprae genotypes in environmental samples.
Main Methods:
- Collected 73 soil samples from Bangladesh, Suriname, and the British Isles.
- Detected M. leprae DNA using RLEP PCR.
- Identified M. leprae genotypes via Sanger sequencing.
Main Results:
- M. leprae DNA was detected in 16.0% of soil samples from leprosy patient houses in Bangladesh.
- DNA was found in 10.7% of soil from armadillo holes in Suriname and 5% from red squirrel habitats in the British Isles.
- Genotype 1 was identified in Bangladesh, while genotypes 1 or 2 were found in Suriname.
Conclusions:
- Mycobacterium leprae DNA is detectable in soil associated with human and animal leprosy cases.
- Environmental soil sources may serve as temporary reservoirs for M. leprae.
- Further research into environmental reservoirs could elucidate leprosy transmission dynamics.
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