New study on nasal bacteria: Can we prevent severe infections?  

A new international study led by SSI sheds new light on the nasal microbiome – the community of bacteria that naturally reside in the nasal cavity. The results show that certain bacteria can inhibit colonization by pathogenic species like Staphylococcus aureus, one of the world’s most common causes of serious infections and deaths.

“We can now see the nasal microbiome in much higher resolution than before,” says Anna Cäcilia Ingham, lead author and researcher at SSI.

She adds:

“This means we can distinguish between different bacterial compositions and better understand why some bacteria persist while others come and go.”

The study, recently published in the scientific journal Cell Reports, is based on nasal samples from over 1,500 individuals in Denmark and Germany. It shows that the nose is typically dominated by either S. aureus or Staphylococcus epidermidis—two bacterial types that are surprisingly stable in their presence, while other staphylococci appear more transient.

Natural protection against infections

A particularly striking finding is that the presence of S. aureus decreases significantly when bacteria such as Dolosigranulum and Corynebacterium are also present in the nose. This suggests that some bacteria may naturally protect us against potentially harmful infections.

“We see a clear pattern where some bacteria establish themselves and remain dominant, while others vary more over time. This has implications for how we understand infection risk—and potentially also how we can influence it,” explains Marc Stegger, co-author of the study and department head at SSI.

The method developed at SSI is based on DNA analysis and can track the presence and variation of staphylococci over time with unprecedented precision – including their interactions and dominance patterns. This provides researchers with new tools to identify risk patterns and potential protective bacterial relationships.

S. aureus is found in the noses of many people without causing symptoms, but it represents a significant infection risk. S. epidermidis, previously considered harmless, is also receiving growing attention as an opportunistic pathogen.

May reduce the need for antibiotics

The study also shows that factors such as age, sex, smoking status, and overall bacterial composition influence which types of staphylococci are present in the nose—and thus possibly also our infection risk.

“The next step is to explore how we might promote the bacteria that naturally suppress S. aureus,” says Anna Cäcilia Ingham, and concludes:

“This could ultimately lead to new ways to protect against infection—and over time reduce the need for antibiotics.”

The findings from the study may therefore represent the first step toward a new approach to infection prevention—based on the body’s own microbiological defenses.

Read the full study in Cell Reports.