Auburn physicists help uncover how staph sticks to skin

Researchers at the College of Sciences and Mathematics have helped reveal how the bacterium Staphylococcus aureus latches onto human skin, a discovery that could lead to new treatments against dangerous infections. The work was published in Science Advances and involved international collaborators in Belgium, France, Ireland and the United Kingdom. 

The study shows that S. aureus uses a protein called SdrD to attach itself to a human skin protein known as desmoglein-1. The bond is strengthened by calcium and is the strongest protein-protein interaction ever recorded in nature — stronger than almost any biological bond previously measured and comparable to covalent chemical bonds. 

“When skin is damaged, calcium levels rise in those areas, which actually helps the bacteria stick even better,” said Rafael Bernardi, associate professor of physics. “That helps explain why infections can get worse when skin is broken or in people with conditions like eczema.” 

For people with atopic dermatitis, also known as eczema, the research suggests why staph infections are common and often severe. Damaged skin changes the distribution of desmoglein-1 and calcium, giving the bacteria more opportunities to attach and making the bond even harder to break. The SdrD protein also contains “shock absorber” domains that unfold one by one under stress, allowing the bacteria to hang on even when skin is being scratched, washed or sweated. 

Priscila Gomes, a research scientist in the Department of Physics, said the discovery points toward possible new therapies.  

“If we can stop this bond from forming at the beginning, we could prevent infections before they take hold,” Gomes said. 

Auburn’s contribution to the project centered on computational modeling. Bernardi’s group used supercomputers to simulate every atom of the bacterial and human proteins, which helped predict exactly how they connect.  

“Our models showed the binding site, and later experiments confirmed we were right,” Bernardi said. 

Gomes said the computer simulations also made the work more efficient. “

The computer helped point straight to the right answer and reduced the number of experiments needed,” Gomes said. 

The team also used atomic force microscopy and single-molecule experiments to measure the interaction directly, giving a complete picture of how the bond works. The research highlights the importance of combining physics with biology and medicine.  

“People don’t always expect a physics department to study infections, but physics is just another tool to solve biological problems,” Bernardi said. 

The next step is to translate the findings into practical treatments. By targeting the way staph attaches to skin, researchers hope to develop new antimicrobial therapies that work alongside or even replace traditional antibiotics.  

“What makes these bacteria so dangerous is not just their resistance to antibiotics, but their ability to hang on when everything else says they should let go,” Bernardi said. “If we can weaken that grip, we open new ways to fight back.”