The algorithm displays the patterns of protein degradation to improve the diagnosis and treatment of infections.

Peptides are small fragments of proteins, mainly found in the skin and mucous membranes. Some peptides act as a barrier, protecting the body from infections by fighting microorganisms such as bacteria, viruses and other pathogens, while others are involved in the regulation of inflammation.

When we have a wound or undergo surgery, this balance can sometimes be disturbed, allowing microorganisms to penetrate and cause an acute infection and, in the worst case, sepsis.

"In order to be able to diagnose infections today, the doctor first conducts a clinical assessment, and then sends a culture sample for further analysis. It usually takes a couple of days to get results on which bacteria are present in the wound, and this does not always give a clear picture of the severity of the infection," says Arthur Schmidtchen, professor of dermatology and venereology at Lund University and consultant at the University Hospital of Skåne, Sweden.

In the infected wound, there is a struggle between the immune system and bacteria. Bacteria break down proteins into peptides to obtain nutrients and spread them, while the body uses similar strategies to fight bacteria and regulate inflammation. This interaction is incredibly complex, it is affected by the types of bacteria present, as well as the severity of the infection.

The research team sought to understand the patterns of protein degradation in order to quickly identify the bacteria involved and assess the risk of sepsis. The increase in antibiotic resistance has also increased the demand for alternative methods of diagnosis and infection control. The work was published in the journal Nature Communications.

"To study the number and types of peptides in the wound, we "squeezed" peptides from wound dressings, and then analyzed them using mass spectrometry. This allowed us to identify up to 45,000 different peptides from one infected wound," says Johan Malmström, professor of mass spectrometry at Lund University.

Researchers are to conduct larger-scale research to further verify the results, improve the methodology and analyze other types of diseases, such as sepsis. They also want to study how this method can be applied clinically in real diagnostic situations in order to assess its practical usefulness.