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  • Antibiotics were the wonder drugs of the 20th century.

  • Now, amazingly antibiotics are responsible

  • for extending the average human life about ten years.

  • But we are currently in the middle of a global crisis where

  • antibiotics are loosing their effectiveness

  • against infectious diseases.

  • The headlines, if you can see them, are very alarming.

  • Bacteria are rapidly becoming resistant

  • to all of the antibiotics that we currently use.

  • Now, in order to understand the nature of this problem,

  • you have to understand bacteria.

  • We live in a world filled with bacteria.

  • Bacteria are everywhere.

  • Everything that you look at,

  • everything you touch,

  • everything you put in your mouth,

  • everything you sit on

  • is covered with millions and millions of bacteria.

  • They're so small

  • that you can't see them without a microscope.

  • But they're there. And they are literally everywhere.

  • You can find them at the bottom of the deepest part of the ocean.

  • You can find them at the top of the tallest mountain.

  • You can even find them in the polar ice caps.

  • They can live in places where there is no sunlight,

  • no oxygen, no food.

  • They can grow in radioactive waste,

  • and in toxic chemicals,

  • and in boiling hot springs.

  • When bacteria find a place where they can survive,

  • they'll multiply fast to very high numbers.

  • Now, one of the places that bacteria like to call home

  • is the human body.

  • A recent survey by microbiologists

  • identified over ten thousand different microbes

  • that live on, or in the human body.

  • In fact, there are more bacterial cells in you

  • than there are human cells.

  • And there are more bacteria genes in you

  • than human genes.

  • So you can argue that each one of you

  • is actually more bacterium than you are human.

  • (Laughter)

  • So, now we have established that

  • I am talking to a room full of bacteria --

  • (Laughter)

  • -- I'm going to flatter the audience here a little bit

  • and tell you that bacteria are amazing organisms.

  • And one of the things that makes them so amazing

  • is their ability to share genes with each other.

  • Now, I need to describe this a little bit more.

  • Because this lies at the heart of how

  • bacteria become resistant to antibiotics.

  • And I don't have any slides,

  • so I'll have to describe it to you.

  • As you probably know:

  • Who you are lies in your genes.

  • So, for example, if you're tall or you have blue eyes

  • is because you have genes that make you tall

  • or that give you blue eyes.

  • And likewise bacteria that can live in Antarctica

  • have genes that make them resistant to the cold.

  • And bacteria that are not killed by penicillin

  • have genes that make them resistant to penicillin.

  • So where did these genes come from?

  • Well, you are familiar with humans,

  • who are born with a set of genes,

  • that they inherit from their parents.

  • And they keep the same genes until the day that they die.

  • So, for example, if you're born with brown eyes,

  • even if you wish that you have blue eyes,

  • your eyes will remain brown until the day that you die.

  • Because these were the genes that you born with.

  • But this is not true for bacteria,

  • who are in a habit of sharing genes with each other

  • in some pretty incredible ways.

  • And one of the ways

  • the bacteria will share genes with each other,

  • is through picking genes up from their surroundings.

  • And they usually do this after one of their neighbors has died.

  • So we're going to refer to this technique as the funeral grab.

  • OK, bacteria Number 1 dies

  • and releases it's genes into the surroundings,

  • and now bacteria Number 2 will pick up some of these genes

  • and pull them in.

  • So now bacteria Number 2 can do something

  • that previously only bacteria Number 1 could do.

  • So this is equivalent of you going to the funeral

  • of someone who had blue eyes,

  • taking a piece of their body out of the casket

  • and eating it.

  • And hey! You have blue eyes too.

  • But now imagine that instead of blue eyes,

  • you now are resistant to tetracycline.

  • Another way that bacteria have

  • to share genes is through viruses.

  • So, yes, bacteria get their version of the flu too.

  • And there are a lot of viruses that will infect bacteria.

  • So, we're going to call this technique: the viral pass.

  • A virus will infect bacteria Number 1

  • and pick up some of its genes,

  • and then inject these genes into bacteria Number 2.

  • Now bacteria Number 2 can do something

  • that previously only bacteria Number 1 could do.

  • So this is the equivalent of you catching the flu

  • from someone who has blue eyes.

  • And after catch the flu, your eyes turn blue too.

  • But, now imagine that instead of blue eyes,

  • you're now resistant to methacycline.

  • And the third way that bacteria share genes is through sex.

  • So, yes, bacteria have sex too.

  • And they're actually pretty promiscuous.

  • So, we're going to refer to this technique

  • as makin' whoopee. (Laughter)

  • So bacteria Number 1, the donor,

  • builds a bridge to bacteria Number 2, the recipient,

  • through which genes are passed

  • from the donor to the recipient -

  • much like sexual activity you're familiar with.

  • But at the end of this sexual activity,

  • bacteria Number 2 can now do something,

  • that previously only bacteria Number 1 could do before sex.

  • So this is the equivalent of having sex with the blue-eyed partner.

  • And after sex, you eyes turn blue too.

  • (Laughter)

  • But now imagine instead of blue eyes,

  • now you are resistant to vancomycin.

  • (Laughter)

  • So you see bacteria have lots of ways

  • to share genes among each other.

  • And with over ten thousand different types of bacteria

  • in the human body alone,

  • not to mention the millions of bacteria everywhere that you look,

  • this is a huge community

  • that's sharing antibiotic-resistant genes with each other.

  • So, now in order to understand antibiotic resistence,

  • you have to understand how antibiotics actually work.

  • So, in many ways bacteria are very different than humans.

  • And what this means is they have a lot of components

  • that can be target by specific chemicals.

  • So antibiotics are fantastic drugs.

  • Because they can kill bacterium without harming the human

  • by recognizing something very specific in the bacterium

  • and not the human.

  • They work like a key and a lock,

  • very specifically finding and binding their target

  • which leads to inactivation of the bacterium.

  • But bacteria have evolved a number

  • of different defensive maneuvers

  • to avoid being killed by antibiotics.

  • So we're going to talk about three ways

  • that bacteria can become resistant.

  • And the first way we are going to call the "up-chuck".

  • The antibiotic targets something specific

  • inside the bacterial cell.

  • But as soon as the antibiotic gets inside,

  • the bacterium barfs it right back out.

  • Preventing it from finding its target.

  • This is a technique that bacteria use

  • to be resistant to tetracycline.

  • Another way we're going to call the "stealth mode".

  • So the antibiotic recognizes something specifically again in the bacterial cell.

  • So the bacterium changes the target just enough,

  • so that the antibiotic no longer recognizes it.

  • The target is in stealth mode.

  • The antibiotic has no effect.

  • And the bacterium is resistant.

  • This is a technique that bacteria use

  • to be resistant to streptomycin.

  • And the third way we're going to call "the ballistic missile defense".

  • The bacteria makes a type of weapon

  • that goes out and finds the antibiotic

  • before the antibiotic can find its target.

  • The bacterium sends out waves of this missiles

  • that breakdown the antibiotic

  • and allow the bacterium to survive.

  • So this is a technique that bacteria actually use

  • to be resistant to penicillin.

  • So you can see that the bacteria have

  • lots of simple and effective ways

  • to avoid being killed by antibiotics,

  • that include things like: upchucks, stealth modes

  • and ballistic missiles.

  • And the genes for these antibiotic resistant mechanisms

  • are shared among the bacteria.

  • Through funeral grabs, viral passes, and makin' whoopee.

  • So remember the important atributes of bacteria:

  • they are small,

  • they multiply fast, and they share genes.

  • Your body is chock-full

  • of millions of good, innocent bacteria,

  • that cause you no harm,

  • they live in a peaceful gated community inside of you.

  • (Laughter)

  • But now let's imagine that

  • some bad bugs move into this neighborhood,

  • and start causing trouble, being obnoxious,

  • playing loud music, trashing the neighborhood.

  • You feel sick.

  • You go to the doctor.

  • You get some antibiotics, and you take them.

  • The antibiotics kill off most of the bad bugs

  • and a lot of good bugs as well.

  • So now you're feeling better,

  • so you stop taking the antibiotics before the doctor prescribed.

  • So what happens next?

  • Well, let's say that one of the good bacteria was already resistant.

  • So when half of the neighborhood dies off

  • from this antibiotic armageddon,

  • it multiplies fast to occupy all the empty houses.

  • As in any war, in order to win,

  • we need to develop new and more powerful weapons

  • to fight and defeat them.

  • And the time to invest in new antibiotic is now,

  • before we're completely out of weapons.

  • This needs to be a continuous, sustained effort.

  • One that really should be considered

  • a global health arms race.

  • With funding support,

  • new antibiotic can be developed continuously,

  • and released continuously into the market.

  • As you can now appreciate,

  • it is inevitable bacteria will eventually become resistant to the next antibiotic.

  • But by this time, the next antibiotic will be ready.

  • A sobering thought is that

  • a number of people in this room

  • are only here today,

  • because antibiotics saved your lives

  • at some point in the past.

  • We need to avoid returning to the pre-antibiotic era,

  • where common bacterial infections,

  • resulting from things like a cut, or a scratch,

  • or a struck throat,

  • could sometimes be a death sentence.

  • In this manner, with new antibiotics,

  • we can maintain the upper hand

  • against the rise of the superbugs.

  • Thank you.

  • (Applause)

Antibiotics were the wonder drugs of the 20th century.

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TEDx】スーパーバグの台頭~抗生物質耐性菌。カール・クロース博士 at TEDxSanAntonio (【TEDx】Rise of the Superbug - Antibiotic-Resistant Bacteria: Dr. Karl Klose at TEDxSanAntonio)

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    Cheng-Hong Liu に公開 2021 年 01 月 14 日
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