American scientists have found that on the skin of healthy cats there is a bacterium with unusual properties. Staphylococcus felis produces antibiotics that may be effective against skin diseases. Thanks to this discovery, new methods of treating diseases in humans and animals may arise.
Identified in healthy cats, the bacterium produces antibiotics that may be effective against severe skin infections found in humans and pets, reports the scientific journal “eLife”.
Skin, both human and animal, is colonized by hundreds of species of bacteria that play an important role in skin health, immunity and fighting infection. Control of pathogens harmful to the skin depends on maintaining a varied balance of the right skin bacteria.
– Our health absolutely depends on “good” bacteria – said prof. Richard L. Gallo of the University of California San Diego School of Medicine. – They live on our healthy skin, and in return some of them protect us from “bad” bacteria. But if we get sick, “bad” bacteria can use our weakened defenses and cause infection, he said.
Professor Gallo’s team specializes in bacteriotherapy, i.e. the use of bacteria and their products to treat diseases. These scientists used bacteria that live on the skin of healthy cats to successfully treat skin infections in mice. According to the authors of the study, these bacteria could serve as the basis for new therapies against severe skin infections in humans, dogs and cats.
To identify candidates for a new bacteriotherapy against skin infections, researchers first screened various bacteria from dogs and cats, and then grew them together with the pathogenic staphylococcus. Staphylococcus pseudintermedius (MRSP) on liquid and agar media. This methicillin-resistant bacterium is common in pets and becomes contagious when sick or injured. MRSP can jump between species and cause severe atopic dermatitis. Such infections are common in dogs and cats, and can also occur in humans, although rates of infection in humans vary around the world. MRSP is resistant to commonly used antibiotics and difficult to treat in clinical and veterinary settings.
Scientists first tested a library of bacteria that normally live on dogs and cats and grew them in the presence of MRSP. Based on this, they identified a strain of cat bacteria called Staphylococcus felisparticularly effective in inhibiting the growth of MRSP. It turned out that this special strain S. felis naturally produces many antibiotics that kill MRSP by damaging its cell wall and increasing the production of toxic free radicals.
“The potential of this species is extreme,” Gallo said. It is extremely effective at killing pathogens, in part because it attacks them from multiple directions – this strategy is known as “polypharmacy.” This makes it particularly attractive as a therapeutic agent, he said.
Bacteria can easily develop resistance to a single antibiotic. To work around this issue, S. felis has four genes that code for four different antimicrobial peptides. Each of these antibiotics can kill MRSP on their own, but by working together they make it harder for bacteria to immunize.
Scientists are planning clinical trials
After determining how S. felis kills MRSP, the next step was to see if it could have any therapeutic effect on a live animal. The team exposed the mice to the most common form of the pathogen and then applied the bacteria to the same site S. felis or bacterial extract. The skin showed a reduction in flaking and redness compared to untreated animals. After treatment S. felis less viable MRSP bacteria were also left on the skin.
Clinical trials are planned to confirm whether S. felis can be used to treat MRSP infections in dogs. Bacteriotherapy could consist of topical application of sprays, creams or gels that contain live bacteria or a purified extract of antimicrobial peptides.
“Keep washing your pets to keep these” good “bacteria out of them, Gallo warned. – The skin has evolved to protect the “good” bacteria, so soap and detergents don’t usually wash them off. It is even possible that living with a healthy cat offers humans some protection against MRSP. This could be an argument to support pet ownership, he said.
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