The study has discovered a toxin, called SElX, which pushes the body’s immune system into overdrive and damages healthy cells.
The toxin is created by 95 per cent of Staphylococcus aureus bacteria, including MRSA strains linked with hospital-acquired infections. When released it triggers an “over-multiplication” of immune cells which can lead to high fever, toxic shock and potentially fatal lung infections.
Scientists said the study, led by the University of Edinburgh, will help research to find drugs which could target SElX and prevent damage to healthy cells.
Dr Ross Fitzgerald, from the university’s Roslin Institute, said: “If we can find ways to target this toxin, we can stop it from triggering an over-reaction of the body’s immune system and prevent severe infections.”
The research was carried out by the Universities of Edinburgh, Iowa and Mississippi State. It looked at a strain of MRSA known as USA300 which can cause severe infections in otherwise healthy individuals.
MRSA strains are known to produce different types of toxins but scientists found that SElX is made by virtually all strains of the superbug.
It belongs to a family of toxins known as superantigens which can invoke an extreme immune response.