💧 Resistant amoebae in drinking water

Tap water, which we consume daily, can sometimes harbor surprisingly resistant microbes. This is what a recent publication reveals, drawing attention to microscopic organisms that are often overlooked, but whose presence could pose a public health problem.

Free-living amoebae are single-celled organisms naturally present in the environment. The majority of them are harmless, but a few species can cause serious illnesses in humans. Their ability to survive in extreme conditions makes them particularly concerning in modern water systems.


These microorganisms can withstand high temperatures and resist common disinfectants like chlorine. Their robustness allows them to colonize water distribution networks, including those believed to be secure. They can even settle permanently in pipes.

Global warming is gradually expanding the areas where these thermophilic amoebae can thrive. Regions that were once unaffected are now seeing these organisms appear, increasing the risks during recreational water activities.

Another lesser-known aspect is their role as a "vehicle" for other pathogens. By hosting bacteria or viruses inside their cells, amoebae protect them from disinfection treatments. This phenomenon could promote the spread of antibiotic-resistant microbes in water.

Faced with this situation, scientists advocate for an integrated approach that links human health, water management, and environmental monitoring. They emphasize the need to improve detection tools and adopt more effective treatment technologies to prevent infections.

The microbial "Trojan horse" mechanism

Some free-living amoebae have the ability to engulf other microorganisms, like bacteria or viruses, and keep them alive inside their cells. This process, often compared to the famous Trojan horse, allows pathogens to hide and evade disinfection treatments designed to eliminate them in water. The amoeba thus acts as a protective shield.

Inside the amoeba, these guest microbes find a favorable environment. They are not only protected from chemical agents like chlorine, but they can also multiply. When conditions become favorable, they can be released into the environment, sometimes in greater numbers or with modified characteristics. This release can occur when the amoeba dies or moves.

This phenomenon has important implications for antibiotic resistance. Bacteria hosted by amoebae can exchange resistance genes among themselves or with other microbes in this confined environment. Then, when these bacteria are released, they can spread this resistance in water systems or even infect humans with reduced sensitivity to treatments.

Understanding this mechanism helps explain why some pathogens persist despite water purification efforts. It shows that the fight against microbes in water cannot be limited to targeting individual pathogens in isolation. We must also take into account these multiple interactions between different organisms, which can guide towards more comprehensive and adapted treatment methods.