17 Sep 2019
Doherty Institute researchers discover mechanism that allows golden staph to evade the immune system
Doherty Institute researchers have discovered a mechanism that switches non-threatening Staphylococcus aureus, also known as golden staph, allowing it to evade the immune system and cause infection.
Golden staph lives in the noses of about 30 per cent of people, without causing any disturbance. However, occasionally the bacteria can escape into the bloodstream causing nasty infections.
Dr Romain Guerillot, a postdoctoral researcher working with Professors Ben Howden and Tim Stinear found that golden staph can flip parts of its chromosome, reshaping bacterial behaviour to promote persistent infection.
“This chromosomal reprogramming likely gives the bacteria a chance to escape their environmental niche in the nose. They become ‘weaponised’ enabling them to survive in a completely different environment in the body, whereby they can cause an infection” Dr Guerillot said.
“The bacterial determinants to thrive in the nose are completely different from those needed to survive in the blood where immune cells are attacking.
“We used advanced genome sequencing approaches to demonstrate that this flip happens in a significant proportion of bacterial cells, suggesting that a sub-population of bacteria living happily in the nose without causing disease, have an intrinsic propensity to cause dangerous infections.”
This discovery can be used to improve diagnostics, as researchers now have the ability to detect these rare, ready-to-invade forms of golden staph.
“For example, if a patient presents for surgery with S. aureus in their nose, one can test beforehand what proportion of bacteria have flipped their chromosome, potentially determining if the patient is at high risk of developing a serious infection” Dr Guerillot explained.
Published today in PNAS, Dr Guerillot and the research team describe their discovery of how S. aureus chromosome flipping makes this pathogen so dangerous.