Salicylic acid is a plant hormone best known for its use as a key ingredient in pain relievers, anti-acne preparations and medications for skin conditions. We also consume mild doses of salicylic acid when we eat fruits and vegetables. An international team of researchers, including scientists from Vetmeduni Vienna, has now shown that this multifaceted compound can also have an unpleasant side effect. Salicylic acid forms complexes with iron, an important trace element for humans as well as bacteria. Laboratory tests showed that iron limitation strongly promotes the formation of biofilms by Staphylococcus aureus. This allows the bacteria to survive and persist in our respiratory tract for longer periods of time which eventually trigger life-threatening infections in immunocompromised persons. The study was published in the journal Frontiers in Microbiology.