"Nature": Rewrite the history of the birth of "super bacteria"!

In the 1940s, the history of modern medicine ushered in an important milestone—the mass production of penicillin gave humans a cure against pathogenic bacteria
.

But soon, the emergence of drug-resistant bacteria greatly reduced the scope of application of penicillin

Among them, methicillin-resistant Staphylococcus aureus (MRSA), discovered in the 1960s, was the first "superbug" that received widespread attention, and they were resistant to methicillin, the most effective antibiotic at that time
.

At the end of the last century, MRSA was widespread in hospitals and society, and was identified by WHO as one of the major threats to human health

Scientists found that MRSA evolved into different strains
.

It is believed that these different strains evolved after the emergence of antibiotics, induced by the misuse of antibiotics

This special "superbug" is called mecC-MRSA, which was first discovered in cows and humans in 2011 by one of the authors of this paper, Professor Mark Holmes of Cambridge University
.

Because these cows were fed a lot of antibiotics, scientists at the time speculated that antibiotic misuse led to the emergence of these resistant bacteria in the cows in the first place

However, as research on mecC-MRSA has grown, the origin of this bacterium has become somewhat puzzling
.

In addition to other domesticated animals such as sheep and horses, mecC-MRSA has been found in wild animals such as wild boars, storks, snakes and hedgehogs

To test this conjecture, a team led by Dr Ewan Harrison of the University of Cambridge first collected 276 hedgehogs from nine European countries and New Zealand
.

As a result, mecC-MRSA was detected in hedgehogs in half of the countries, and two-thirds of hedgehogs in the UK carried the strain

Subsequently, the research team further sequenced the mecC-MRSA and S.
aureus carried by these hedgehogs, as well as a large number of S.
aureus from other sources.
These analyses can tell us the evolutionary history of mecC-MRSA
.

By comparing the number of mutations in different strains of MRSA, the research team speculates that mecC-MRSA appeared in hedgehogs about 200 years ago, long before the birth of methicillin (1959)
.

▲ Schematic diagram of the reaction between the fungus T.
erinacei and MRSA in a petri dish (Photo credit: Claire L.
Raisen)

Why did natural evolution bring these resistant bacteria to hedgehogs? The answer has to do with a fungus on their skin
.

Studies have shown that this fungus, Trichophyton erinacei, can secrete two β-lactam antibiotics (the familiar penicillins and cephalosporins belong to this category)

▲The evolutionary history of MRSA (Image source: Reference [1])

"Superbugs" are everywhere in hedgehogs, but that doesn't mean we're on the fence about it
.

After all, this bacterium has been following the hedgehog for two centuries, but the number of people infected with mecC-MRSA is very small, accounting for only 1/200 of all MRSA infections

But what we really need to worry about from this study is that resistance may be born for more common causes than we thought
.
It also reminds us that we need to be more cautious about the use of antibiotics, because "resistance is everywhere
.

Because the antibiotics we use today are mainly from nature, the researchers caution that resistance to these antibiotics may already be present in nature
.
Once antibiotics continue to be abused in hospitals or on farms, creating favorable conditions for the growth of resistant strains, it may be a matter of time before antibiotics eventually fail
.

Note: The original text has been deleted

References:

[1] Larsen, J.
, Raisen, CL, Ba, X.
et al.
Emergence of methicillin resistance predates the clinical use of antibiotics.
Nature (2022).
https://doi.
org/10.
1038/s41586-021-04265 -w

[2] Superbug MRSA arose in hedgehogs long before clinical use of antibiotics.
Retrieved Jan.
5, 2022 from https:// A type of MRSA evolved in hedgehogs long before the first antibiotics.
Retrieved Jan.
5, 2022 from https:// -long-before-the-first-antibiotics/