Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp.j. That's y-A-K-U-L-T.C-O.jp. When it comes to a guide for your gut, count on Yacolt.

This is Scientific American's 60-second science. I'm Christopher in Taliatta.

Perhaps the chief poster child of antibiotic resistance is metacillin-resistant Staphylococcus aureus, or Mersa.

The bacterium's impervious to a suite of antibiotics, and it can cause blood infections, pneumonia, even death.

And you'd assume that it developed its namesake resistance

to methicillin by being exposed to metacillin. But that doesn't seem to be the case. Instead,

the culprit for resistance appears to be an earlier and chemically related antibiotic,

penicillin. We think it's a very early use of penicillin that was around, that then forced the strains to

pick up these mechanisms.

Matthew Holden, a molecular microbiologist at the University of St. Andrews in Scotland.

Holden and his team analyzed the genomes of freeze-dried strains of Mercer bacteria, from the 1960s to the 80s.

In effect, what we were doing was sort of genomic archaeology in looking at the genomes

and comparing the variation and using that information to effectively reconstruct the evolutionary

history.

What they found was that the staff bacteria seemed to have acquired the metacillin resistance

gene in the mid-1940s, about 15 years before metacillin even

hit the market, and they determined that it was the widespread use of penicillin that led to that

adaptation. The results are in the journal Genome Biology. Methacillin was introduced in the UK in

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