Location: Infectious Bacterial Diseases ResearchTitle: Environmental Mycobacterium avium subsp. paratuberculosis hosted by free-living amoebae Author
Submitted to: Frontiers in Cellular and Infection Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2018
Publication Date: 2/9/2018
Citation: Samba-Louaka, A., Robino, E., Cochard, T., Branger, M., Delafont, V., Aucher, W., Wambeke, W., Bannantine, J.P., Biet, F., Hechard, Y. 2018. Environmental Mycobacterium avium subsp. paratuberculosis hosted by free-living amoebae. Frontiers in Cellular and Infection Microbiology. 8:28. https://doi.org/10.3389/fcimb.2018.00028. Interpretive Summary: This study takes a unique look at the possibility of Mycobacterium avium subspecies paratuberculosis (MAP) transmission to dairy cattle through water-bourne amoeba. MAP is known to cause Johne's disease in cattle, sheep and other ruminants. The bacteria are also known to be transmitted by the fecal-oral route. But could MAP also be transmitted by drinking in the water toughs on farm? The data from this study suggest that this is a possibility. We found that several MAP strains were not only able to survive in amoeba for up to 72 hrs, but the same genetically typed strains were found in both the water-bourne amoeba in a drinking trough as well as from cows on the same farm. These results may be of use to animal producers who want to block on farm transmission of MAP by monitoring water drinking sources.
Technical Abstract: Mycobacterium avium subsp. paratuberculosis is responsible for paratuberculosis in animals. This disease, leading to an inflammation of the gastrointestinal tract, has a high impact on animal health and an important economic burden. The environmental life cycle of Mycobacterium avium subsp. paratuberculosis is poorly understood and several studies suggest that free-living amoebae might be a potential environmental host. Free-living amoebae are protozoa found in water and soil that are described as reservoirs of pathogenic bacteria in the environment. Indeed, bacteria able to survive within these amoebae would survive phagocytosis from immune cells. In this study, we assessed the in vitro interactions between several strains of Mycobacterium avium subsp. paratuberculosis and Acanthamoeba castellanii. The results indicate that the bacteria were able to grow within the amoeba and that they can survive for several days within their host. To explore the presence of Mycobacterium avium subsp. paratuberculosis in environmental amoebae, we sampled water from farms positive for paratuberculosis. A Mycobacterium avium subsp. paratuberculosis strain was detected within an environmental amoeba identified as moderatly related to the poorly described Rosculus genus. The bacterial strain was genotyped, showing that it was similar to previous infectious strains isolated from cattle. In conclusion, we described that various Mycobacterium avium subsp. paratuberculosis strains were able to grow within amoebae and that these bacteria could be found on farm within amoebae isolated from the cattle environment. It validates that infected amoebae might be a reservoir and vector for the transmission of Mycobacterium avium subsp. paratuberculosis.