MRSA super bugs evolved in hedgehogs long before antibiotics were used

Under the spiny spines of the European hedgehog, microbial stand-off may have propagated dangerous drug-resistant pathogens long before the era of human antibiotic use.

Jesper Larsen, a veterinarian at Statens Serum Institut in Copenhagen, undoubtedly accelerates the drug resistance of bacteria that colonize humans when antibiotics are used. But he says these microbes had to get genes from somewhere to make them resistant, and scientists don’t know where most of these genes came from.

Well, for one type of methicillin resistance Staphylococcus aureus, Or MRSA, Larsen and colleagues Tracking the evolution to hedgehogs hundreds of years ago..In the skin of these creatures, natural antibiotic-producing fungi may have created an environment in which drug resistance evolves within the bacterium, researchers report on January 5. Nature..

MRSA, one of the most common drug-resistant pathogens, infects hundreds of thousands of people worldwide each year, and these infections can be difficult to treat. Certain types of MRSA, which new studies are focusing on, cause a small proportion of human cases.

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The team happened to be the first MRSA in a hedgehog when biologist Sophie Rasmussen, now at Oxford University, approached Larsen’s team about sampling a freezer full of dead hedgehogs, as part of a new job. I found it in. Of these animals collected from Denmark 61 percent had MRSA.. “We found this very high prevalence in hedgehogs,” says Larsen, suggesting that the animals were a reservoir of drug-resistant superbugs.

In a new study, scientists investigated hedgehogs (Erinaceuseuropaeus When Erinaceus roumanicus) From 10 European countries and New Zealand. Workers at the Wildlife Rescue Center wiped the noses, skin and feet of 276 animals. MRSA was widespread in hedgehogs in the United Kingdom, Scandinavia and the Czech Republic.

analyse Staphylococcus aureus, The team has 16 shares mecC-MRSA is named after the genes that confer resistance and mapped the evolutionary relationships between them by comparing gene instruction manuals or genome-wide mutations. From the analysis, the team speculates that the three oldest strains of hedgehog populations appeared 130-200 years ago, long before penicillin hit the market in the 1940s, and regularly infected humans and cattle. did. Researchers report that hedgehogs may be the source of 9 of the 16 strains.

“There is no doubt that the use of antibiotics is the main driver of resistance to human pathogens,” says Anders Larsen, a microbiologist at the Statens Serum Insect, who was also a member of the team. “This is a very special case and can be traced back to the origin.”

But that’s how the hedgehog Staphylococcus aureus Developed a resistor. The team got clues from research in the 1960s. Trichophyton erinacei, A fungus that causes “ringworm” in humans.The research is T. erinacei Some people were killed by the hedgehog’s skin Staphylococcus aureus However, others who are resistant to penicillin do not.Growing T. erinacei In the lab, researchers identified two penicillin-like antibiotics excreted by the fungus.

The findings suggest that Hedgehog is a reservoir of MRSA. This is because they “live with their cheeks close to each other that produce penicillin.”

The fungi “live in a bad neighborhood,” says Wright.They have to compete with other microorganisms, for example Staphylococcus aureus, For resources and places to colonize on the host, and “they must come up with this arrangement that can protect themselves.”

Wright says you can’t think of antibiotic resistance without considering its connection to the environment. He says that evolution of resistance is a step-by-step process shaped by natural selection. Wright’s studies show that antibiotic resistance has an ancient origin in places free from human influence.People searched for this Evolution mainly in soil microbial communities, Or the microbial flora (SN: February 14, 2006). However, he says, the animal microflora provides another potential source of resistant genes and sources of new antibiotics.

The history of antibiotics in the last century is a cycle of new drug discovery, and soon microbial resistance develops in those drugs. That’s not surprising, Wright says. “Antibiotics have been on the planet for billions of years, and resistance is billions of years old,” he says. If scientists don’t really understand where resistance comes from, he says, even if researchers discover new drugs, all we’re doing is catching up.