How long do bacteria live? It depends.
This time last year, the Australian continent was around 1.2 inches further south than it is today.
Its landmass has been gradually drifting northwards ever since its split with Antarctica around 45 million years ago.
Also around that time up in Myanmar (formerly Burma) in the Northern Hemisphere, traces of yeast became trapped in tree resin that became fossilized and went on to become amber.
In 2009 a Cal Poly biology professor claimed to have extracted the yeast and brought it back to life.
Now I’m not sure exactly how he chose to celebrate his achievement, but I have a pretty good idea.
You see, he went on to co-found the Fossil Fuels Brewing Company, which made beer using what was claimed to be 45-million-year-old yeast.
Apparently it had a clove-like taste, with tinges of ginger and pineapple.
Actually that sounds more like a cocktail than a beer to me, but each to their own.
The lifespan of microorganisms varies widely, and they can sometimes survive for considerable lengths of time in a kind of suspended animation.
Back in 2000, researchers from West Chester University in Pennsylvania claimed that they’d been able to extract Bacillus bacteria from salt crystals found 2,000 feet below ground in New Mexico, which they revived and grew after placing in a nutrient solution.
Although some questioned their findings, there’s widespread agreement that bacteria can lay dormant for long periods and yet still be capable of rejuvenation.
Where there’s disagreement is in just how long bacteria can survive.
Experts on our team say it’s almost certainly way, way less than some claim.
But what about the bacteria that are most involved with human health, though?
How long do they live?
Here the picture becomes less clear for, as we saw a couple of weeks ago, bacteria tends to reproduce through a process called binary fission, in which one cell splits into two identical “clones”.
In some cases this happens pretty frequently.
Most scientists view this as one “mother” becoming two “twin daughters” but a few reject that model, suggesting that the mother cell doesn’t die or transform into a new daughter immediately after division.
Perhaps, they say, the relationship between two cells formed by division is of the mother-daughter type, rather than two twin sisters?
It’s an interesting idea, which of course would rather muddy the waters about how long bacteria actually live.
Although the bacteria in your gut are reproducing all the time, the overall composition of your microbiome probably doesn’t change that much over time.
Researchers at The Gordon Lab at Washington University’s School of Medicine in St Louis followed 37 adults over a five year period, finding that 70% of their gut bacteria stayed the same after one year, and in fact 60% were stable across the whole five years.
Of course when it comes to human health we have to concern ourselves with bacteria’s longevity outside the body as well as inside.
Staphylococcus aureus, the bacteria that can cause MRSA infections, can live on hard surfaces for weeks because, unlike other bugs, it doesn’t need moisture.
Clostridium difficile has been known to survive for 5 months in the environment, and Bacillus anthracis, the anthrax bacteria, can form exoskeleton-like spores allowing it to survive tens or even hundreds of years.
Better get busy with that disinfecting.
Not everyone steers clear of old bacteria, however.
In a widely reported—but perhaps a little far-fetched—story, Russian scientist Anatoli Brouchkov recently injected himself with what he said was 3.5-million-year-old Bacillus F bacteria that he and his team said they had found in permafrost in a part of Northern Siberia lived in by the Yakut people, who have a reputation for living longer, healthier lives.
Brouchkov wondered whether the bacteria, which he believed to have their own long-life qualities, might play a part in keeping people going.
Whether or not you choose to believe this, best not try it at home, though.
And definitely don’t get your Bacillus bacteria muddled—there’s a world of difference between Bacillus F and Bacillus anthracis.