The Deadliest Being on Planet Earth – The Bacteriophage

[Music] A war has been raging for billions of years, killing trillions every single day, while we don’t even notice. The war is fought by the single deadliest entity on our planet: the bacteriophage or ‘phage’ for short. [Intro + Music] A phage is a virus; not quite alive, not quite dead. Also, they look as if someone made them up. Their head is an icosahedron, a sort of dice with 20 faces and 30 edges. It contains the genetic material of the virus and often sits on a long tail that has leg-like fibers. There are more phages on earth than every other organism combined, including bacteria. And they are probably everywhere living things exist. Billions are on your hands, in your intestines and your eyelids right now. Which might make you nervous since phages are responsible for the majority of deaths on earth but you’re lucky. While they do commit genocide for breakfast, they only kill bacteria. Up to 40% of all bacteria in the oceans are killed by them every single day. But phages also have major flaws. Like any other virus, phages need a host to survive and reproduce. They’re not much more than genetic material in a hull and they specialize. Usually, a phage has chosen one specific bacteria and maybe some of its very close relatives. These are its prey. Imagine a phage as like a cruise missile that only hunts and kills members of one very unlucky family. When a phage finds its victim, it connects its tail fibers with receptors and uses a sort of syringe to puncture a surface. In a weird motion, the phage squeezes its tail and injects its genetic information. Within minutes, the bacteria is taken over. It’s now forced to manufacture all the parts of new phages. They only stop when the bacteria is filled up with brand-new phages. In the final step, they produce ‘endolysin’, a powerful enzyme that punches a hole in the bacteria. The pressure is so high that the bacteria sort of vomits out all of its insides and dies. New phages are released and begin the cycle anew. In the last few years, bacteriophages have enjoyed the attention of the second deadliest beings on earth: humans. Recently, we’ve started looking into injecting millions of them into our bodies because we’re sort of getting desperate; we screwed up. In the past a single cut or a sip from the wrong puddle could kill you. Bacteria were our phages. Tiny monsters that hunted us mercilessly. But then, about 100 years ago, we found a solution in nature. By accident, we found fungi that produced compounds that killed bacteria: antibiotics. Suddenly, we had a powerful super weapon. Antibiotics were so effective that we stopped thinking of bacteria as monsters. Only the old and the weakest among us were killed by them. We used antibiotics more and more for less and less serious causes. We lost respect for the monsters and the weapon But bacteria are living things that evolve and one by one they started to become immune against our weapons. This continued until we had created what are called ‘superbugs’, bacteria immune to almost everything we have. This immunity is spreading across the world as we speak. By 2050, superbugs could kill more humans a year than cancer. The days when a cut or bladder infection or a cough could kill you or your loved ones are coming back. In the US alone, more than 23,000 people die from resistant bacteria each year. But it turns out that phages, our tiny killer virus robots, could save us. We can inject them into our bodies to help cure infections. Hold on, how could injecting millions of viruses into an infection be a good idea? Phages are very very specialized killers of bacteria. So specialized, in fact, that humans are completely immune to them; we are too different. We encounter billions of phages every day and we just politely ignore each other. Antibiotics are like carpet bombing, killing everything even the good bacteria in our intestines that we don’t want to harm Phages are like guided missiles that only attack what they’re supposed to Wait a minute, if we use phages to kill bacteria, won’t bacteria develop ways of defending themselves? Well, it’s more complex than that; phages evolved too. There has been an arms race between them and bacteria for billions of years and so far, they’re doing great. This makes phages smart weapons that are constantly getting better at killing. But even if bacteria were to become immune against our phage, we still might be able to win. It turns out that in order to become resistant to even just a few species of phages, bacteria have to give up their resistance to antibiotics. We might be able to trap them in a catch-22. This has already been successfully tested with a patient who had no other hope left The bacteria ‘Pseudomonas Aeruginosa’, one of the most feared bacteria, infected the man’s chest cavity. They are naturally resistant to most antibiotics and can even survive an alcoholic hand gel. After years of suffering, a few thousand phages were directly inserted into his chest cavity together with antibiotics the bacteria were immune to. After a few weeks, the infections had completely disappeared. Unfortunately, this treatment is still experimental and pharma companies are still reluctant to invest the necessary billions in a treatment that has no official approval yet. But things are finally changing. In 2016, the largest phage clinical trial to date began and phages are getting more and more attention. and we better get used to it because the era in which antibiotics have been our super weapon is drawing to a close. It might be a weird concept but injecting the deadliest being on planet Earth directly into our bodies could save millions of lives This video was made possible by a grant from the Bill & Melinda Gates Foundation If you’d like to support Kurzgesagt, you can do so on and get fancy things in return.


  1. There's brand new stuff in the Kurzgesagt Merch Shop. Check it out here:

  2. "The enemy of my enemy is my friend" Never thought that would apply to medicine XD

  3. Spinel injector

  4. I remember watching this guy before I went to sleep when I was a kid

  5. Good document & the best to follow. The clever jokes by commentators. Laughter is the best medicine!

  6. To date, just 390K thumbs up, but only 3.8k thumbs down. I wonder who thumbs it down? Anti-vaxxers perhaps?

  7. I smell a copy of the INFOGRAPHICS SHOW

  8. This looks like the injector from Steven universe the movie

  9. So,some people dont know that all Viruses are specific killers?

  10. what if after all the injecting of this super weapon phages, we start to evolve, and then phage production fuses in your cells ( just like mitochondria) and become immune to all bacteria 0_0

  11. Specialised justice watriors that kill only the invading harmful bacteria? Or do they also target the useful bacteria that live in symbiotic relationships with the rest of the body? This is more curiosity. Are there phages that target "good" bacteria?

  12. That is off of steven unuverse,just shape differently

  13. I promise I'm not one of those people but I legit thought this was a Steven Universe movie video.

  14. Nah that’s just spinels injector

  15. The wilhelm scream

  16. Am i the only one who notices that it looks like an injector from steven universe, or well the injector looks like a phage

  17. The world war we never knew about

  18. But the phage may get Greedy…
    then Our bodies will become their Reproduction Facility XD
    can this happen?

  19. The thumbnail looks like the injector from Steven Universe

  20. We need a vacation for Phage

  21. Phages are my hero lmao

  22. When the two deadliest things on Earth work together

  23. This video trying to make out phage as our friends but really its just scott ridley alien exploding out of a civilian.

  24. But if phages kills all the bacteria they will start killing humans

  25. Superbacteria: Ha! I'm immune to antibiotics now!

    Super antibiotics: sips tea.

  26. Bacteria: I will take over this body muahahahaha'

    Phage: I will kill you >:)

    Bacteria: you can't you did not choose me as the bacteria you can kill XD


  27. Bacteria: HARD CHOICE immune so Phage or Antibiotics

    Phage: Antibiotics please I want attention from humans

    Bacteria: music plays ye you just want a attention

  28. Whats worse then bacteria 🦠 a bacteria bacteria 😳

  29. phages for life

  30. Looks Like Those Drills In The Kinder Garten From Steven Universe

  31. I thought it was an injector from Steven universe


  33. I’m convinced that thumbnail is spinels injector

  34. Ofcourse the pharmaceutical companies wont approve it because they will loose billions of dollars because there is more money with treating something than to cure something

  35. It is disgusting how the pharmaceutical companies value money over human lives they just want tons of money if you are poor then you die and if you rich you live

  36. Kurzezagtz how is that a dangerous entity in our world even doe they are

  37. so ehm
    i just got this in mind
    if phages were like disease busters just like in the movie resident evil?
    yea anyways as we know the desperate alice seems to be cured by the virus that got injected to her
    and then this new disease buster was formed but soon enough they turned our backs and killed us becoming zombies
    now i wonder if this could happen…

  38. Sees thumbnail
    My brain: ThAt'S rIgHt I hEArd tHe StorY oVeR anD oveR aGaIn

  39. Mosquito: I am the most dangerous-
    Bacteriophage: Hold my bacteria

  40. Bacteria:let's have me some human cells to reproduce😉


  41. Whats the music?

  42. how come all hand sanitizers kill 999.9?

  43. Omg whats going to happen to the anti vaxxers once we start using viruses to kill bacteria?

  44. Thank god they only kill bacteria

  45. Bacteria: I am the strongest thing alive

    Phages: imma bout to end this mans whole career

  46. im allergic to antibiotics .-.

  47. poor living mac & cheese in the start of the video

    RIP living mac & cheese 1 sec – 4 sec

  48. So our symbiosis with phage
    Is it parasitism,commensalism or mutualism

  49. Me:gets a cut and bacteria get inside
    Ignores it
    Immune system:WAKANDA FOREVA!

  50. Spinel' injector is that you?

  51. It looks like the injectior on stevan universe

  52. Love that subtle willhelm scream

  53. I love how cute the animation is

  54. WRONG construction of bacteriophage ,.. They have maximum 5 legs … but here in starting of video you showed 6 legs ..🤔🤔

  55. Jews giving germans money :p

  56. Bacteriophage is good or bad?

  57. This channel's comment section is filled with autistic 12 year olds making unfunny and unoriginal comments

  58. 2084: 'Well, then the bacteria evolved to defend against phages and antibiotics…which is when the phages just evolved to kill humans. The next virus that would effect humanity would be a computer virus.'

  59. Bacteria1: we evolved now we are invincible
    Bacteria2:Dude look at that phage he has cannon!!
    Bacteria1:wait what!?

  60. where are the sources asking cause i have a presentation about this and sources would be awesome

  61. 0:11 that looks like spinel's injector

    in Steven Universe

  62. Did you know Russia has been using bacterial phage therapy since the 1950's. It's cheap and easy.

    Did you also know it illegal in the USA because of the laws using genetic material in medicine.

  63. Astonishing video. Really great work!!!

  64. it looks like the injectors from steven universe

  65. Hey kurzgesagt a Hispan youtuber has copied
    vídeo, is

  66. Bro wut if we had some dr.stone stuff happen to us and we had phages and all of human evolution that we experienced is actually ancient technology to the ancients

  67. Plot twist: bacteriaphages are ancient alien mircobots sent as a gift from aliens because they knew that we will need them in the future and they need our help in the future so they need us to survive until they come

  68. Beatiful video, i from russia and me interestig

  69. Phage looks like the injector in steven universe

  70. how does this guy have barely any subscribers compared to his views, show him some love guys!!!

  71. Making "The Owner" itch till his last breath

  72. Phages kill 40% of bacteria every day?! This just speaks to how radically excessive bacteria multiply.

  73. Big pharma will probably fuck this up cause they care more about money

  74. After watching these videos I realized that

    Everything in existence kills us

  75. this is so interesting 🙂

  76. Phages create by aliens 😀

  77. Can it kill cancer?

  78. Super bug:Fools! Now i am immune to antibiotics!
    Phages:well yes but actually no

  79. So can it kill cancef bacteria/cells?

  80. DC- Superman
    Marvel- Captain Marvel
    Nature- Bacteriophage…



  83. Bacteria: Finally I am immortal
    Phages: Allow us to introduce ouerselves

  84. I often do mistake with organism and orgasm😖😖😖

  85. 1:59 wait why does this kinda looks familiar ?

  86. This kind of feels like hiring mercenaries to assist the immune system. I like it!

  87. These videos scare me, then make feel better

  88. Well bacteriophage could be useful for curing people with infective bacteria we just have to find the right type

  89. If phages are already in us, why doesn’t it already do that?

  90. Humans: Antibiotics

    Bacteria: Become resistant

    Bacteria: lololol u are die now

    Humans and Phages: no u

  91. I want to study… This fuckers

  92. Won't bacteriophage kill helpful bacteria?

  93. LIKE si en el minuto 3:34 te acordó a Plague Inc

  94. i thought humans were the most deadliest:(

  95. This is the best video from the series.

  96. Phages: why don't we just eat the human cells…

  97. I love this this video 😍😍🥰🥰🥰😍🥰🙂

  98. is Melinda Gate fundation a good fundation? I read they have private interests, they invert in bad companies

  99. Option 1:can fight the anti biotic and phages can kick your bottom
    Option 2:can fight phages and let the anti biotic kick your bottom

  100. Jesus christ…imagine if they gain the ability to infect human cells…that will be messy.

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