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Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection
Nuno Santos1,2, Catarina Santos1,2, Teresa Valente3
1Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
Plos One
|November 13, 2015
Summary
Environmental Mycobacterium tuberculosis complex (MTC) DNA is widespread, supporting bovine tuberculosis transmission. An improved detection method found higher MTC contamination in infected areas and specific environmental samples like dam sediment.
Area of Science:
- Veterinary Microbiology
- Environmental Science
- Epidemiology
Background:
- Environmental contamination by Mycobacterium tuberculosis complex (MTC) is key to bovine tuberculosis (bTB) persistence in complex ecosystems.
- Detecting MTC in the environment has been challenging due to methodological limitations.
Purpose of the Study:
- To develop and validate an improved protocol for MTC DNA detection in environmental samples.
- To assess the prevalence and distribution of MTC contamination in the Iberian Peninsula.
- To investigate the role of environmental MTC in bovine tuberculosis transmission.
Main Methods:
- Development of an improved protocol for MTC DNA detection.
- Quantification of MTC DNA concentration using the Most Probable Number (MPN) method.
- Analysis of environmental samples (water, sediment) from the Iberian Peninsula.
Main Results:
- MTC DNA contamination was widespread across various environmental samples.
- MTC DNA prevalence was higher in bTB-infected areas (32%) compared to presumed negative areas (18%).
- Detection rates varied by sample type (sediment: 22%, water: 5%) and season, with higher DNA concentration in autumn.
Conclusions:
- The improved protocol effectively detects MTC DNA in environmental samples.
- Widespread environmental MTC contamination supports indirect transmission as a factor in bovine tuberculosis maintenance.
- Further investigation into Mycobacterium bovis/caprae DNA in environmental samples from infected areas is warranted.
