Rhogostoma minus is the most common amoeba in wastewater treatment plants worldwide. It can serve as a host for bacteria of the order Legionellales, which includes pathogens such as Legionella pneumophila, the cause of Legionnaires’ disease
Researchers from Professor Michael Bonkowski’s working group at the University of Cologne’s Institute of Zoology have found that Rhogostoma minus is the most common amoeba in wastewater treatment plants worldwide and also serves as a host for Legionellales. The Legionellales identified in the amoebae were previously undescribed, so it is not clear whether these amoebae can cause disease in humans. A recent article by the same research group (see link below) had already shown that Rhogostoma also hosts the dangerous Legionella bacteria, whose species cause Legionnaires’ disease. ’This strongly suggests that these amoebae may be potential hosts for human pathogens,’ said leading researcher of the study Nina Pohl. Study leader Dr Kenneth Dumack added, ’These connections and insights into the role of amoebae in wastewater treatment plants as breeding grounds for pathogenic bacteria may help to clarify infection pathways in the future to ultimately prevent further contagions.’
Nina Pohl, Marcel Dominik Solbach, and Kenneth Dumack have published the results of their article ’The wastewater protist Rhogostoma minus (Thecofilosea, Rhizaria) is abundant, widespread, and hosts Legionellales’ in the journal Water Research.
Amoebae belong to the so-called complex unicellular organisms. They serve as hosts for the bacterial order Legionellales and are thus possible vectors of Legionnaires’ disease. Yet little is known about them so far. Although wastewater treatment plants obviously function well, to date a large proportion of the microorganisms within them are poorly understood. In addition to the useful water purifying microorganisms, parasites are also washed into the wastewater treatment plants via sewage. It is still unclear how they spread and when this leads to disease outbreaks. It is therefore not surprising that in the past there have been repeated outbreaks of disease around wastewater treatment plants and contaminated drinking water.
The bacteria of the order Legionellales can cause, among other things, the so-called Legionnaires’ disease. As soon as the bacteria enter the lungs through aerosols or droplets, they can trigger pneumonia, which can sometimes be fatal. To date, however, it is unclear when these Legionellales become prevalent in wastewater treatment plants and what causes them to proliferate. This question, as well as whether the bacteria found are actually dangerous to humans, will have to be clarified by future research.