Natural Environments are rich sources of human pathogen predative amoebae

 By: Maria Hernandez

The figure shows amoebae isolated from a compost site using different strains as food source. The different strains used are A. baumannii and K. penumoniae and are represented with blue, red and orange circles respectively. Open circles represent isolated amoebae. Figure taken from Bornier et al. 2021. 

Amoebae, which can be found in both aquatic and terrestrial environments under a wide variety of temperatures, are natural regulators of microorganism populations in the environment. Easy-to-grow Amoebae such as Acanthamoeba catellanii and Dictyostelium discoideum have been used as models for the identification of factors that could contribute to virulence in mammalian hosts. The purpose of the study was to test if environmental free-living amoebae from compost would or could predate on human pathogens. The researchers found that natural environments are rich sources of amoebae with a large range of bactericidal activities. Therefore, the findings in the study are important because they show how amoebae can predate on human pathogens including those that are highly virulent and clinical isolates resistant to antibiotics. However, when the soil bacteria are exposed to complex bacterial communities, they often discriminate and only feed on specific bacteria. In addition, in natural settings, wild amoebae consume higher numbers of encapsulated bacteria. The researchers inform that while amoebae grown axenically in laboratories don't accurately reflect the natural relationship between amoebae and human pathogens, natural environments are rich in potential sources of amoebae with broad-spectrum predatory activities. 

Article:

Bornier F., Zas E., Potheret D., Laaberki M.H., Coupat-Goutaland B., Charpentier X. (2021). Environmental Free-Living Amoebae Can Predate on Diverse Antibiotic-Resistant Human Pathogens. Applied and Environmental Microbiology.