(UPBEAT MUSIC).
BIANCA BRISCAS: When I ask you to picture fungi, what's the first thing that you see?
Probably mushrooms sitting in the Produce aisle of
the grocery store or crinkling inside a brown paper bag.
The chewy stringy stuff that you get in really good ramen.
Or maybe you see those lawn mushrooms that sometimes
pop up in the grass after lots of rain.
Maybe you get a glimpse of the mould that's growing on those veggies you
swore that you were going to cook dinner with two - no, three weeks ago.
Or do you think of the really gross stuff?
A crusty yellow toenail, a flaky chunk of skin,
white circles coating someone's tongue?
Oh, yuck.
Sorry.
Even still, I bet none of you pictured
fungi living in your own intestines.
And look, I can't really blame you.
It's only been 400 years since we realised that there are teeny,
tiny things growing everywhere you could possibly imagine.
The development of germ theory, the understanding
that microbes like bacteria,
viruses and fungi are responsible for infectious disease
revolutionised almost every aspect of human behaviour,
and it also kickstarted the longest-running war in human history.
For a while, we didn't even know we were fighting this war.
In fact, if the existence of the Earth was condensed to just 24 hours,
microbes have been battling it out from about 4 am,
and humans have just shown up with less than 2 minutes to midnight.
To say we're late to the party is an understatement.
And look, we've done our best to get involved,
but there's only so much we can do as latecomers
to a 4 billion-year-old war.
At first, we blamed disease on anything that we could think of,
from the wrath of various vengeful deities to a misalignment
of the planets to breathing in bad air.
Eventually, though, after some guy mucking around with
a glorified magnifying glass discovered microorganisms,
humanity caught on and we started to fight back.
Now, don't get me wrong, germ theory wasn't exactly embraced
by the medical and scientific community at the time,
or, as the last few years have shown us, by the general public either.
Who would have thought actually having a bath
more than once a year and maybe washing
the scalpel before you remove someone's appendix
could make such a huge difference?
In between all these minor changes - wash your hands, wear a mask,
get a vaccine, you know the drill - a much larger goal emerged.
Scientists, doctors and naturopaths alike began
the search for a so-called magic bullet,
a perfectly targeted treatment designed
to selectively kill disease-causing
microbes without causing any damage to the human body.
Most people tend to forget that the first antibiotic designed
to kill bacteria originally came from a fungus.
Millions of years of evolutionary battle between
microbes had given us an ideal solution.
So when penicillin was discovered, isolated and purified,
its use became widespread to treat diseases caused by bacteria.
This was the golden age of antibiotics, and now we've got
nearly 200 different antibacterial drugs at our disposal.
Fungi, however, put up a bit more of a fight.
It took almost 30 years longer than it did for bacteria,
but eventually, we developed the first antifungal drug.
Unfortunately, we haven't actually made
a whole lot of progress since then.
We're still waiting for the golden age of antifungals.
Quite literally, I can count on one hand the different types
of antifungal drugs that are currently on the market.
It's five.
So why is developing antifungal drugs such a challenge?
Well, because fungal cells are so similar to human cells,
anything that's toxic to fungi is likely to be toxic to humans too.
Drug development is incredibly expensive and time-consuming,
and resistance to antimicrobial drugs complicates things even further.
We might have won the battle, but we are definitely losing the war.
And when it comes to this war between microbes and humans,
most people don't even see fungi as a threat.
But fungal infections kill nearly 1.7 million people every single year.
That's nearly 5,000 deaths a week.
One of the leading causes of fungal infection is Candida Albicans.
You've never heard of it, I know.
Or if you have, you're thinking of skin rashes and yeast infections.
But it couldn't happen to you, right?
I mean, fungal infections are, like, rare and gross.
Right?
Well, I've got good news and bad news.
The bad news is that at least 60% of you have
this fungus living in your gut right now,
and you can't get rid of it either.
It's not found in the environment or in animals.
It's evolved alongside the host that's us and has adapted to survive in
almost every niche and crevice of your body that you can think of.
In healthy people, this fungus doesn't cause any harm.
It has to compete with all the other microbes in your gut.
It's blocked off from your bloodstream
and other organs by the lining of your gut.
And if it does somehow manage to escape,
it's quickly dealt with by your immune system.
However, if something changes in this complex balance, like,
all the healthy bacteria disappear because you've taken antibiotics,
your gut lining gets damaged because of surgery or illness,
and your immune system decides to pack up and go on holiday,
Candida albicans can become a serious problem.
It can overgrow, escape the gut, and hitch a ride in your bloodstream
to major organs like the liver, spleen and kidneys.
Eventually, this can kill you.
And in most cases, these infections are caused by
the Candida albicans already living inside your gut.
Now, look, I'm not trying to scare you, I promise.
This is the good news.
These infections only affect people who are already
seriously ill and immunocompromised.
Candida albicans isn't out to get you.
It only causes disease if and when it is given the opportunity.
That doesn't mean we shouldn't take it seriously, though.
Remember, there's five classes of antifungal drugs.
Well, only three of them can be used to treat
infections caused by Candida albicans.
And even though we give patients antifungal drugs,
nearly 50% of people who get these systemic infections still die.
Like I said, we might have won the battle,
but we are definitely losing the war.
So what can we do?
Clearly, drug development isn't the answer.
It's difficult, expensive and takes way too long.
And even if we do somehow manage to make a new one,
at best, it's another Band-Aid solution.
Over and over again, we've tried the same
thing and it simply isn't working.
So is there another way to think about fungal infection?
Instead of treating people that are already sick,
why don't we stop them from getting sick in the first place?
We've found a way to use fungi against bacteria,
but what if we could use bacteria against fungi?
My research is trying to find bacteria that are already
part of the healthy human gut microbiome
that are also capable of killing Candida
albicans without causing us any harm.
If we know a patient has Candida albicans already living in their gut,
we could use these bacteria to clear it before they take antibiotics,
have surgery or become immunocompromised and get rid of Candida
albicans before it ever even has a chance to become a problem.
So how are we doing this?
We used a specialised model.
A tiny glass jar filled with a liquid medium that
replicates the conditions of the human gut.
That means there's no oxygen, really limited nutrients,
trace amounts of vitamins and minerals, and an acidic pH.
When we add Candida albicans into these gut-simulating conditions,
it can survive in relatively small numbers,
just like it does in your gut.
This means we can add in samples of the gut microbiota from
healthy humans and see what happens to Candida albicans.
And what we've seen so far is pretty exciting.
Some human samples are able to kill Candida albicans completely,
while other human samples have no effect
on Candida albicans survival at all.
So the next question is obvious.
What is so special about the human samples
that can kill Candida albicans?
Well, it's been shown that there are specific bacteria only detected
in the human samples that have an anti-candida effect.
This is how we expand our arsenal against fungal infection.
Not through drug development, not by treating
people that are already sick,
but by looking inside us, literally,
to find these anti-candida bacteria.
For eons, microorganisms have been locked in an evolutionary battle.
If we can find a way to capitalise on this
ancient war that started long before
us and will probably continue long after us,
we might just stand a chance.
The not-so-secret secret to fighting fungal infection is this: It
has nothing to do with fungi and everything to do with bacteria.