Discovery: a yeast thriving on our skin fights superbugs 🦠

The human skin hosts a multitude of microorganisms, including fungi that could play a key role in our health. A recent study reveals how a common yeast produces substances capable of combating pathogenic bacteria.

Researchers from the University of Oregon have identified a molecule produced by the yeast Malassezia, present on the skin, which shows promising antimicrobial properties. This discovery opens new perspectives in the fight against antibiotic-resistant infections, a major public health issue.


The molecule in question is a hydroxy fatty acid, produced by Malassezia sympodialis from skin lipids. It works by destroying the membranes of Staphylococcus aureus bacteria, responsible for hospital-acquired infections. This rapid and selective action could inspire new treatments.

The study, published in Current Biology, highlights the importance of skin pH in the effectiveness of this molecule. In the lab, acidic conditions similar to those of human skin were crucial for observing the antimicrobial effect, a variable often overlooked in previous research.

Despite its potential, bacterial resistance to this molecule has also been observed. Researchers identified genetic mutations in Staphylococcus aureus that allow it to survive the attack of hydroxy fatty acids.

This discovery sheds light on the interactions between skin microorganisms and their environment. It suggests that the skin microbiome, still poorly explored, could harbor other therapeutic molecules. Researchers now plan to study these resistance mechanisms in greater detail.

How do hydroxy fatty acids work against bacteria?

The hydroxy fatty acids produced by Malassezia sympodialis act by disrupting the cell membrane of Staphylococcus aureus bacteria. This disruption causes leakage of cellular contents, leading to bacterial death.

These molecules exhibit remarkable specificity, targeting only certain bacteria without affecting human cells. This selectivity is due to the unique structure of bacterial membranes, which differ from those of eukaryotic cells.

The effectiveness of these fatty acids strongly depends on environmental conditions, particularly pH. An acidic environment, like that of human skin, optimizes their antimicrobial activity, which explains why their potential has long been underestimated in the lab.