healthHealth and Medicine

Major "Superbug" Lineage First Evolved 450 Million Years Ago


Robin Andrews

Science & Policy Writer


This strain of bacteria appeared just as the colonization of land began in earnest. Mark Witton

Antibiotic resistance, sometimes known as antimicrobial resistance (AMR), is a deeply troubling modern phenomenon. It’s worth pointing out, however, that certain strains of bacteria have always been more resistant to antibiotics than others – and some of these lineages are truly ancient.

As a new study in the journal Cell has revealed, one such lineage goes back 450 million years, a period of time following the first great explosion of complex life on Earth. This particular group, the Enterococci, exists today and some of its strains are some of the most prominent hospital “superbugs” that medical professionals are struggling to eradicate.


“By analyzing the genomes and behaviors of today's Enterococci, we were able to rewind the clock back to their earliest existence and piece together a picture of how these organisms were shaped into what they are today,” co-corresponding author Ashlee Earl, group leader for the Bacterial Genomics Group at the Broad Institute of MIT and Harvard, said in a statement.

Based on their genomic rewinding, the team found that this group has always been resistant to dryness, disinfectants, and prolonged periods of starvation. They have also been long resistant to a wide range of antibiotics, which probably explains how their lineage has survived for nearly half a billion years.

An Enterococcus bacteria specimen. CDC

Like all bacteria, their defense mechanisms evolved gradually over time.

Bacteria emerged as early as 4.1 billion years ago, and they have proliferated across the world ever since. They can be found in every single environment, even the most extreme – and as a result of this, they’ve developed some nifty features, including the use of, and resistance to, antibiotics.

Remember, antibiotics aren’t a human invention, even if we helped to cultivate them upon their discovery. Antibiotic just means “against life” – they are a diverse range of biochemicals produced by a wide range of bacteria and fungi, mainly to kill off their competition. The Enterococci are a particularly hardy group, and thanks to their AMR, they’ve been on quite the journey.


They followed the migration of life onto land, all the way up through various mass extinctions, including the Great Dying 252 million years ago. They mingled in the guts of the dinosaurs, and made it through the famous asteroid impact that brought their era crashing down.

Ultimately, they made it into the gut linings of humans, where some of them are still utilizing the same AMR genes they first acquired all those eons ago.

It’s safe to say that they have been incredibly patient bacteria. In order to beat them, we need to take a leaf out of their book, use antibiotics very sparingly, and hope that researchers conjure up a rather ingenious way to remove their dangerous brethren from the planet.


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  • antibiotic resistance,

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  • 450 million years ago