The most detailed study so far on the mechanisms by which a common type of bacterium, Staphylococcus aureus, adapts to living on the human body could improve the prevention, diagnosis and treatment of certain infections, say researchers.
The study, from the Wellcome Sanger Institute, the University of Cambridge, the Institute of Biomedicine of Valencia at the Spanish National Research Council (CSIC) and collaborators, used the genomes of thousands of S. aureus isolates cultured from the human nose and skin to uncover which genes are important for the bacteria to adapt and persist.
Gram stain of the bacterium, Staphylococcus aureus.
A new approach to analysing the genomes from human carriers highlighted how they adapt in their natural habitat, revealing key mutations that enable certain strains to evade the human immune system and become resistant to antibiotics.
Several genes and biological pathways not previously known to be involved in S. aureus colonisation were revealed.
S. aureus is carried in the nose of up to 30 per cent of people and can be found on the skin or intestine. It can get into the bloodstream and cause infections, ranging from mild skin and soft tissue infections to more severe infections, including sepsis and pneumonia.
Dr Ewan Harrison, senior author from the Wellcome Sanger Institute, said: “While Staphylococcus aureus bacteria are harmless to many people, for others they can cause potentially life-threatening infections. Our study gives a detailed new understanding of how these bacteria adapt and evolve in order to survive on and in their human carriers at a genetic level.
“Through our new analysis, we were able to study these strains in their natural habitat; highlighting previously unknown mutations that give certain Staphylococcus aureus strains the upper hand. We hope that further investigation of the pathways we have uncovered will help improve the prevention, diagnosis, and treatment of infections caused by these bacteria.”
Dr Francesc Coll, first author from the Institute of Biomedicine of Valencia at the Spanish National Research Council (CSIC), said: “Understanding how bacteria respond to antibiotic treatments has made it possible to identify the genetic changes that allow them to survive the attack of antibiotics. These mutations can be used as diagnostic markers, as well as to design new therapeutic strategies and a more rational and effective use of antibiotics.
“Studies of bacterial adaptation like this could also reveal mechanisms of immune evasion – how bacteria adapt to evade recognition and attack by our immune system. This could help identify new antigens, components of the bacteria that the immune system recognises as foreign or dangerous, and design new vaccines.”