Leprosy-causing bacterium's DNA detected in soil

By: Elizabeth Maldonado 

Leprosy is a contagious illness caused by the Mycobacterium leprae organism. This disease affects the skin and nerves of infected humans, which is the reason why it is considered a major health threat. In a study conducted by Tió-Coma and colleagues (2019), it was investigated whether the DNA of this organism could be found in the soil of regions where leprosy is common. To detect the presence of this organism in the collected samples, polymerase chain reaction (PCR) amplification was performed. PCR is a highly specific laboratory technique utilized to make copies of a DNA segment. This allows scientists to identify genetic material by detecting and amplifying a region of the bacterium's genetic sequence. The results revealed that the DNA of M. leprae was present in the soil in proximity to houses of leprosy patients in Bangladesh. It was also discovered in the holes of armadillos located in Suriname, and in the habitat of leprosy-carrying red squirrels in the British Isles. This suggests that the DNA of M. leprae can be found in the soil, indicating that the environment could serve as a temporary bank for this bacteria.

In this figure, a gel for the PCR amplification is shown. Lanes 2 to 4 demonstrate the samples collected in Suriname, lanes 5 to 14 were from the samples collected in Bangladesh, lane 15 shows the DNA of M. leprae (Thai-53 strain), lane 16 is the negative control, and lanes 1 and 17 are the molecular weight markers for comparison. The genetic material of M. leprae was detected in the soil samples.

Original article: Tió-Coma, M., Wijnands, T., Pierneef, L. et al. Detection of Mycobacterium leprae DNA in soil: multiple needles in the haystack. Sci Rep 9, 3165 (2019). https://doi.org/10.1038/s41598-019-39746-6