The Billion Year Quest For New Antibiotics
Less than a century since the discovery of antibiotics, superbugs are becoming resistant to them. Can we find new antibiotics before they all stop working?
Antibiotics revolutionized the world. They improved the live of billions by treating diseases that had plagued humanity since the dawn of time.
Now the diseases are returning. One by one, the antibiotics we have relied upon for the last century are becoming ineffective.
And it’s all because of evolution.
The bacteria that cause these diseases are evolving a resistance to our antibiotics.
But the next antibiotics just might be hiding in a billion years of natural selection.
World War One was one of the deadliest conflicts in human history. Almost 20 million people died during the 4 years it was waged. The development of the machine gun and modern warfare tactics had ratcheted up the carnage to a level never before seen.
But not all died in battle.
Fully 1/3 of military deaths were caused by infection.
Sir Alexander Fleming saw this first hand.
During the war, he was a physician serving on the Western Front in France. With few medical alternatives available, Fleming could do hardly more than watch as millions of soldiers who had survived the horrors of battle succumbed to the microscopic conflict in their bodies.
Years later, with the experience of World War One still fresh in his memory, Fleming would make a mistake that would change the world forever.
After accidentally allowing a culture of staphylococcus bacteria to be contaminated by mold, he noticed that the invading fungus produced a substance that killed the bacterial colony.
This substance would eventually be called Penicillin.
The first antibiotic
An antibiotic is a medicine or compound that inhibits the growth of bacteria or other microorganisms.
Today we take antibiotics for granted. You get sick. You go to the doctor. They prescribe an antibiotic and you’re better in a few days.
But for thousands of generations, our bodies have been locked in a microscopic war with the bacterial world. Before antibiotics very little could be done to stem the tide of infection.
Scratches could kill. Disease spread mostly unchecked. The poor and the unfortunate, children and the old were usually the first casualties in this war — but no one was completely safe.
And you’d definitely want to think twice about going in for surgery or having a baby.
But after Fleming’s accidental discovery, the tide of war began to change.
In the 19th century, nearly a quarter of all deaths in Europe could be attributed to Tuberculosis. Tuberculosis is a respiratory disease. It has plagued humanity since antiquity.
And in that time, doctors had tried all kinds of treatments, ranging from pressing coins against the throat to isolating people in caverns.
But nothing could really stop the disease.
That is, until a group of scientists isolated Streptomycin in 1944 — the first antibiotic effective against Tuberculosis.
And by 1950, the Tuberculosis mortality rate had dropped 90%.
For thousands of years, we’d been fighting this disease. It now looked like we could finally bring the war to an end.
But in recent decades, drug-resistant forms of Tuberculosis have cropped up. In 1993 the World Health Organization declared a global health emergency in the face of this new strain of Tuberculosis.
And every year it’s estimated that a half a million new cases of Tuberculosis appear of which there is no effective antibiotic treatment.
And Tuberculosis isn’t the only disease experiencing a resurgence.
Drug-resistant E. coli, Gonorrhea, and over a dozen other diseases have been identified. Even a variety of the Staphylococcus bacteria that Fleming used to develop Penicillin has become resistant to most — if not all — of our antibiotics.
Today, we have hundreds of different kinds of antibiotics. Some of them are many times as powerful as Penicillin. We need this wide variety of antibiotics to tackle the wide variety of bacteria that attack our bodies.
But despite our best efforts, antibiotics can’t kill every bacteria that comes along. Every so often an antibiotic will encounter a strain of bacteria that it can’t kill. This surviving bacteria then go on to multiply — generation after generation — until the entire population is resistant to the drug.
This is a superbug.
There are three ways this can happen.
The superbug could just happen to be naturally resistant to the drug.
Or, a genetic mutation could bestow resistance on a population that was previously susceptible to a drug.
Or, resistance can be transferred from one species of bacteria to another by exchanging genetic information.
In other words, the bacteria are responding just as they always have — just as any organism responds to a changing environment. They are evolving.
So the appearance of these resistant strains was more or less inevitable. It’s just life doing what it does best — surviving.
But the way we have used (or more precisely misused) antibiotics has only intensified the problem.
Ever since we started using antibiotics, we have been placing an evolutionary pressure on the bacteria. An evolutionary pressure is any cause that results in a higher reproductive success rate for an organism.
So every time you take an antibiotic, you are essentially killing off all the weak bacteria and leaving all the strong bacteria to go on and reproduce, creating entire populations of fitter, better adapted superbugs.
Now this isn’t to say you shouldn’t use antibiotics at all — they are certainly necessary in many situations — but we must be careful not to misuse them or overuse them.
For instance, an antibiotic is useless against a virus. The common cold is caused by a virus. But the most common case that an antibiotic is prescribed for is the common cold. Now this isn’t because doctors don’t know that antibiotics are useless against colds. Often physicians are just being extra careful and prescribing antibiotics just in case.
Patient misuse of antibiotics is another big factor.
Not finishing a prescribed dosage of antibiotics or not taking the drug properly can leave semi-resistant populations of bacteria alive in your system, making the appearance of a fully resistant population more likely.
But one of the biggest factors leading to drug resistant bacteria doesn’t have anything to do with their use in humans.
Over 70% of the antibiotics produced in the United States are used in animal husbandry. We give them to livestock not only to ward off infection but to promote growth. The antibiotics are mixed in with their food and administered over long periods of time at low doses to large numbers of animals. This creates the perfect environment to cultivate armies of superbugs.
Yet another reason we see the appearance of drug-resistant bacteria has nothing to do with evolution at all.
Because they are less lucrative than other kinds of medicines, pharmaceutical companies don’t have as much incentive to invest in the research and development of new antibiotics. So antibiotics often get sidelined or ignored entirely in favor of more profitable drugs.
That means when a drug-resistant bacteria appears, we don’t have a new antibiotic in the pipeline ready to combat it.
But this doesn’t mean we have to go back to being at the mercy of infectious disease.
It means our drugs need to evolve in step with the bacteria.
And the answer might already be in development far from any laboratory.
Researchers have been combing the planet for organisms that have evolved in isolation or in environments hostile to most other forms of life. The hope is to find novel antibacterial substances that these superbugs have never had a chance to evolve a resistance to because they have never encountered that organism or environment.
That means exploring the deepest parts of the ocean or the most inhospitable deserts for organisms that have evolved unique and deadly defense mechanisms against bacteria.
This exploration into the extreme recesses of nature coupled with state of the art genetic mining techniques could help us assemble a library of bacteria-killing genes. Essentially giving us access to all the weaponry that life on earth has been amassing for the past billion years or so.
Bacteria far outnumber us.
There are more bacteria on the planet than there are stars in the sky. And you could argue that this world is more theirs than ours. Has been for billions of years. And this war we’ve waged against bacteria was a lost cause before it even began, before antibiotics, long before we even got here.
But that doesn’t mean we have to give up. Far from it. Like any conflict, the key to victory is knowing your enemy — not eradicating them. By recognizing that the mechanics of survival are not exclusive to humans but universal amongst all life on this planet, we just might be able to forge a lasting truce. One that might endure for another billion years.
Watch the episode: https://youtu.be/nbMBHhVXfu0