Pathogens: Certain bacteria influence the spread of Legionella
In the past few years, a significant increase in the number of Legionella was registered infections. In people with a weakened immune system such diseases can be fatal. Researchers have now discovered a new factor in the spread of dangerous bacteria.
Treatment of the disease is in the foreground
In the case of a bacterial infection, the treatment of the disease is always in the foreground. But where does this disease come from pathogens, and where they live, if they occur in connection with an infection? An international team of researchers led by Matthias Horn from the center for Microbiology and environmental system science at the University of Vienna has examined this on the example of a pathogen of lung disease. The results of their study were published in the journal “mBio”.
Legionellosis be life-threatening
Legionella pneumophila, the causative agent of Legionnaires ‘ disease (legionellosis), an atypical pneumonia that is for healthy people is rather harmless.
In people with weakened immune systems can be life-threatening, such as in a communication is declared.
The number of diseases caused by Legionella bacteria is increased in the 2000s worldwide is steadily increasing.
“Since the introduction of legionellosis reporting requirement in the year 2001 a continuous increase in the case of registered numbers have stabilized in recent years at around 600 diseases”, reported the Robert Koch Institute (RKI).
The last major outbreak in Europe occurred in September 2018 in the Italian city of Brescia. At that time, 400 patients ill of pneumonia and were treated in the hospital.
In Infected breast and a headache, cough, chills and high fever of 39 to 40.5 degrees develop very quickly.
It can also cause dizziness to more serious States of Confusion. In addition, the abdomen occur occasionally pain with diarrhea and vomiting.
The pneumonia is often difficult, and takes around four weeks. They can also be fatal, shows a case in Bremen, where a man of Legionella has died.
Legionella bacteria are also found in water pipe systems
The natural habitat of Legionella are sediments of lakes and rivers, however, they are also found in water piping systems.
“There they multiply in individual learning, which you destroy, then,” said Matthias Horn from the newly established centre for Microbiology and environmental system science, conducted a study with his Team and colleagues at the renowned Institute Pasteur and the University of Michigan the lives of Legionella in individual learning.
“This feature allows legionellae, the infection of the people. The disease usually comes only after Legionella in individual learning have increased“, explains the expert.
Protection against pathogens
To survive with the ability in individual learning Legionella are not alone. Unicellular organisms often accommodate other bacteria that do not harm them, however, so-called endosymbionts.
The team of scientists has now found that these bacteria have a decisive influence on the multiplication and dissemination of Legionella.
In numerous experiments, the researchers were able to prove that Legionella can multiply in amoebae, if this endosymbiont.
Surprisingly, most of the amoebae to survive with the endosymbionts of the otherwise lethal infection with Legionella.
“Those bacteria that had multiplied in advance in amoebae with endosymbiont, were significantly less infectious, and were therefore able to attack far less efficient new amoeba,” explains Lena king, first author of the study and a doctoral candidate at the centre for Microbiology and environmental system science.
Gene expression of the bacteria considered to be more accurate
In order to better understand what is happening within amoebae, the same time as endosymbionts harboring of Legionella-infected, have considered the experts, the gene expression of both bacteria in more detail.
“The RNA-sequencing allows the determination of biological events, which take place within the protozoa,” says Cecilia Wentrup, who was involved as a Post-doctoral researcher instrumental in the project.
“We have found an explanation for the reduction of the infectivity of Legionella. These appear to be the subject, namely, the natural endosymbionts of the amoeba in the competition for nutrients, both of which require of the individual learning,“ adds king.
The result is that Legionella bacteria multiply more slowly and are not able to produce for the infection of amoebae and human factors necessary. The pathogens are, for example, is not movable, and it is important storage substances.
Important factor in the proliferation and dissemination of Legionella
The Team also made a further observation: the growth of stop work not only with the commonly used laboratory strains, but also with fresh from the environment-derived amoebae, as well as with recently isolated Legionella.
Endosymbionts of amoebae are not only under laboratory conditions, but probably also in the environment as an important factor in the proliferation and dissemination of Legionella.
This appears to be especially interesting, because most of the protozoa under natural conditions, the bacterial symbionts.
As it says in the message, makes the current study an important contribution to a better understanding of the lifestyle of these bacterial pathogens in the environment. (ad)