Not tasty: parasitic amoebas are in the mouth of many people, as a study now reveals. These unicellular organisms are close relatives of the amoebic dysentery and occur in around 80 percent of patients with gingivitis, but also in some healthy people. The parasites penetrate the oral mucosa and destroy the tissue there. This could explain why many gum infections are so persistent and difficult to eliminate.
Our oral cavity is anything but sterile – that much is clear. Because on our tongue, on the gums, on the mucous membranes and in the saliva tons of different microbes live. A kiss alone can transmit around 80 million bacteria. The majority of these roommates are completely harmless, but they also include pathogens that cause gum infections, among other things.
Periodontitis patients more affected
But as it turns out, there are other, unsavory roommates in our mouth: amoebas of the species Entamoeba gingivalis. These unicellular parasites are close relatives of the amoeba that triggers the infamous amoebic dysentery – one of the most common causes of death from parasites in the world. With this disease, the parasites eat their way into the intestinal mucosa, trigger severe diarrhea and ultimately destroy the tissue.
Because of this unappetizing relationship, a research team led by Arne Schäfer from Charité – Universitätsmedizin Berlin has now investigated how often the parasite Entamoeba gingivalis occurs in the oral cavity. It was found that these amoeba are very common and abundant, especially in the mouth of people with gingivitis. In 80 percent of the 158 patients with periodontitis examined and 15 percent of the healthy control subjects, the researchers found Entamoeba gingivalis in the gum pockets.
As destructive as the amoebic dysentery
But what does this amoeba do in the gums? As the researchers found out using cell culture experiments, this unicellular organism not only settles on our mucous membranes, it also penetrates the gum tissue. There the amoeba destroys the cells, absorbs their contents and thereby kills them. “As a result, more bacteria can enter and further increase inflammation and tissue destruction,” explains Schäfer. This will destroy the tissue over time.
The Mundamöbe thus behaves similarly to its relatives triggering amoebic dysentery. “Entamoeba gingivalis actively contributes to tissue destruction in the gums and activates the same defense mechanisms of the human host as E. histolytica during the invasion into the intestinal mucosa,” explains Schäfer. “The parasite that can be transmitted by simple droplet infection is therefore a possible cause of serious oral inflammatory diseases,” says Schäfer.
Explanation for persistent gum infections
This destructive effect of the oral amoeba could also explain why many severe gum infections are so persistent and difficult to cure: if you only fight the bacteria, the amoeba can still destroy the tissue. “So far, neither the infection nor the successful elimination of this parasite has been considered in the treatment of periodontitis,” says Schäfer. To make matters worse, Entamoeba species are often resistant to the body’s own immune cells and antimicrobial peptides. Antibiotics often don’t work either.
In a follow-up study, the scientists now want to clarify whether targeted control and elimination of the oral amoeba are more effective against recurring gum infections. (Journal of Dental Research, 2020; doi: 10.1177 / 0022034520901738)
Source: Charité – Universitätsmedizin Berlin
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