A lethal superbug, responsible for over a million fatalities worldwide each year, might have a surprising counteractor that exists right on our skin.
This essential player is a type of natural yeast known as Malassezia sympodialis, one of the most common microorganisms found on healthy human skin. Recent studies indicate that while it helps cleanse the skin of oil and fat, this yeast also generates a fatty acid that inhibits the growth of staph infections.
Laboratory experiments conducted by researchers at the University of Oregon have shown that M. sympodialis can counteract Staphylococcus aureus bacteria through its acidic byproducts.
Because the acid produced by the yeast is typically present in healthy skin, scientists believe it prevents S. aureus from excessively colonizing the microbiome. While S. aureus is a normal part of the skin’s microbiome, its overgrowth or invasion into tissues can lead to severe infections.
Skin and soft tissue infections from S. aureus result in around 500,000 hospitalizations each year in the United States. Moreover, this bacterium can develop resistance to all classes of antibiotics currently available.
Consequently, there’s a continuous need for new therapeutic options to combat its harmful effects. Exploring the natural defenses of our skin microbiome against staph infections could be quite significant.
“Many studies focus on identifying new antibiotic structures,” states Caitlin Kowalski, the lead investigator and evolutionary biologist at UO. “What was fascinating about our research is that we recognized a compound that is already well-known yet had been somewhat neglected.”
The compound under discussion is called 10-hydroxy palmitic acid (10-HP). It’s likely that its antimicrobial properties were overlooked in the past since it only exerts its toxic effects in low pH environments, like skin, rather than in standard laboratory settings.
Researchers utilized human skin samples from healthy volunteers and discovered that the acid was indeed produced by resident Malassezia yeast.
“It was akin to finding a needle in a haystack, but with invisible molecules,” remarked Matthew Barber, Kowalski’s advisor.
In laboratory tests, Barber and his team examined how M. sympodialis yeast affects different strains of S. aureus. After two hours of treatment with the yeast, most S. aureus strains displayed more than a 100-fold decrease in viability.
Over time, some strains of S. aureus did develop a degree of resistance to 10-HP from M. sympodialis, resembling the behavior seen with clinical antibiotics.
Interestingly, other Staphylococcus species that don’t pose the same danger as S. aureus have already found ways to coexist with M. sympodialis.
“Considering how prevalent Malassezia is in mammalian skin, we are likely just beginning to scratch the surface of its role in shaping microbial interactions and building resistance in this niche,” the authors note.
Kowalski is planning to delve deeper into the genetic mechanisms behind antibiotic-resistant staph infections to understand how the bacteria swiftly adapt to evade various antimicrobial treatments.
“There’s still a great deal we need to learn about these microorganisms and discover new strategies for treating or even preventing these infections,” Barber concluded.
The findings were published in Current Biology.
