How does Streptococcus aureus form a biofilm

03.02.2017 08:55

Active ingredient salicylic acid promotes colonization of the nose by Staphylococcus aureus

Mag.rer.nat Georg Mair Public Relations and Communication
University of Veterinary Medicine, Vienna

The plant hormone salicylic acid is a widely used active ingredient. We consume a small dose simply by consuming fruits and vegetables. A research team with scientists from Vetmeduni Vienna has now shown that the versatile active ingredient also has an unpleasant side effect. It forms a complex with iron, an important trace element. Laboratory tests showed that Staphylococcus aureus forms a stronger biofilm due to the iron deficiency. This allows the bacterium to survive longer in our respiratory tract and can also trigger life-threatening infections if the immune system is weakened. The study was published in the journal Frontiers in Microbiology.

The bacterium Staphylococcus aureus settles in the upper respiratory tract in around a quarter of the population. Normally there is no health risk because these bacteria are opportunists. If the host is doing well and if they are optimally cared for, then they behave calmly and are kept in check by the immune system. They only become active when infected by other pathogens or a disease.
However, the colonization could be unexpectedly prolonged through the regular consumption of the active ingredient salicylic acid, or when there is pain, as a study by the research group led by Monika Ehling-Schulz from the Institute of Microbiology at the Vetmeduni Vienna with the research group led by Fernanda Buzzola from the University of Buenos Aires has now shown. The research stays were supported by the mobility promotion program of the Scientific-Technical Cooperation (WTZ) of Austria and Argentina.

Salicylic acid removes iron from the body and triggers defense mechanisms against bacteria

Iron is an important trace element for the human body. It plays an essential role in blood formation. The metabolism of many bacteria, such as Staphylococcus aureus, also depends on the availability of iron molecules. Salicylic acid forms a complex with the iron ions in the blood and thus removes this trace element not only from us but also from the staphylococci. If the microorganisms have too little or no trace element available, they change their metabolism. They react to the changed and for them negative conditions and strengthen their biofilm, a kind of slime layer that the bacteria form together, explains Tom Grunert from the Institute of Microbiology at Vetmeduni Vienna. With a reinforced biofilm, they can survive an even longer period of unfavorable living conditions.
Exactly this reinforcement is supported by regular or increased consumption of salicylic acid. As a medication, the active ingredient is usually not taken regularly. However, the plant hormone is also a component of acne drugs and certain peeling products. People who eat a predominantly vegetarian diet are also affected. Salicylic acid is also found in fruits, fruits, and vegetables. "This means that you eat a small dose of the active ingredient almost every day," says Grunert. Appropriate medication increases the loss further. Salicylic acid enters the bloodstream through oral ingestion, where it forms the complex with iron ions.

Laboratory test shows that the biofilm is strengthened when salicylic acid is administered

The research team has proven this effect in laboratory tests. “We first confirmed that salicylic acid really“ captures ”the iron that is so important for staphylococci, says Grunert. Because it is actually known that the plant hormone is a complexing agent. The fact that the biofilm of the bacteria is formed was finally shown with different doses of the active ingredient. "For this we let the staphylococci grow in a special, iron-containing medium, ie a nutrient solution, in laboratory vessels." The addition of salicylic acid was finally able to determine a further strengthening of the biofilm. In addition, the treatment of mice with salicylic acid showed that Staphylococcus aureus was able to colonize the nasal mucosa for longer.
"We were able to show that frequent consumption of salicylic acid or a vegetarian lifestyle can support the colonization of the upper respiratory tract with Staphylococcus aureus," explains Grunert. This could help make staph infections more lengthy and difficult to treat.

The article "The Active Component of Aspirin, Salicylic Acid, Promotes Staphylococcus aureus Biofilm Formation in a PIA-dependent Manner" by Cristian Dotto, Andrea Lombarte Serrat, Natalia Cattelan, María S. Barbagelata, Osvaldo M. Yantorno, Daniel O. Sordelli, Monika Ehling-Schulz, Tom Grunert, and Fernanda R. Buzzola was published in Frontiers in Microbiology.

Via the University of Veterinary Medicine, Vienna
The University of Veterinary Medicine Vienna (Vetmeduni Vienna) is one of the leading veterinary, academic, educational and research institutions in Europe. Her main focus is on the research areas of animal health, food safety, animal husbandry and animal welfare, as well as biomedical principles. The Vetmeduni Vienna employs 1,300 people and is currently training 2,300 students. The campus in Vienna Floridsdorf has five university clinics and numerous research facilities. Two research institutes on Vienna's Wilhelminenberg and a teaching and research facility in Lower Austria also belong to the Vetmeduni Vienna.

Scientific contact:
Dr.rer.nat. Tom Grunert
Functional Microbiology Department
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-2469
[email protected]

Mag.rer.nat. Georg Mair
Science communication / public relations and communication
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1165
[email protected]

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