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Very naive question: won't bacteria lose their resistance after a while? What if we cycle certain antibiotics on an annual basis? When we reintroduce them, they

by naz 10y ago

Very naive question: won't bacteria lose their resistance after a while? What if we cycle certain antibiotics on an annual basis? When we reintroduce them, they'll be more powerful. Right?

strebler 10y ago
I'm not sure, but that sounds like it might work. The real problem is: good luck getting all hospitals in the world to agree on a rotated schedule of which antibiotics to use / not use and when.
- crimsonalucard 10y ago
  We are not enforcing a rotating schedule but hospitals are already naturally rotating antibiotics in response to resistance. Once penicillin was lost we switched to another antibiotic. The problem is that we don't have enough classes of antibiotics restart the cycle. It takes way longer for bacteria to lose resistance than for bacteria to gain resistance.
simonbarker87 10y ago
I was chatting to doctor friend recently who has a masters in this area and he said that in theory yes but it would likely require the bacteria to have a reason to loose the mutation that caused the resistance in the first place so there is no guarantee.
- crimsonalucard 10y ago
  Your doctor friend is incorrect. Unused traits will be lost eventually through the accumulation of random mutations. In order for a trait to form and be stable in an organism, selection pressure must not just be applied... it must be maintained. This backwards process is actually observable. Many fish living in underground caves have lost their eyes through evolution. While eyes don't aid a fish in surviving in the dark, they certainly don't hinder the fish from surviving either... Yet cave fish have lost their eyes despite the lack of negative selection pressure.
  - cariaso 10y ago
    > Many fish living in underground caves have lost their eyes through evolution. some have, yes. but in order to get the antibiotic benefit we're looking for, you'd need to have ALL fish having lost their eyes. That's a much higher bar. ( https://en.wikipedia.org/wiki/Blind_fish https://en.wikipedia.org/wiki/Blind_fish seems to be a reasonably comprhensive list ). We also need the antibiotics to be viable again in a reasonable timespan ( a decade or two?), in order to be useful -- not on the timescale that was involved in cavefish eye degeneration.
    - deleted 10y ago
      [deleted]
    - crimsonalucard 10y ago
      Bacteria mutate much quicker than fish. Generations of bacteria form within minutes. There is significant possibility in the viability of cycling antibiotics as bacteria lose resistance.
- ocschwar 10y ago
  The reason is there: bacteria have to be stingy in how much DNA they devote to anything.
  - simonbarker87 10y ago
    Sounds reasonable, we were chatting about it briefly in a noisy pub so he would have glossed over details.
ocschwar 10y ago
If you can get the entire human race to match in lockstep with rotating antibiotics in and out, AND the array of antibiotics is large enough, then yes, that's exactly what would happen. The second part is in the works, constantly. The first part, however, is proving difficult.
cariaso 10y ago
> won't bacteria lose their resistance after a while? DNA is good at accumulating, and relatively poor at editing out. Some bacteria will lose resistance, just like your ancestors lost the ability to make Vitamin C. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145266/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145266/ but you only need one single bacteria to have not lost the ability. > What if we cycle certain antibiotics on an annual basis? it helps. We can also stack them, and use multiple attacks at the same time. which also helps. But it just delays the inevitable. > When we reintroduce them, they'll be more powerful. Right? the bacteria, yes. because they'll have accumulated defense mechanisms. Ultimately, I think we win this race, because we can intelligently and actively edit DNA.
mikeleung 10y ago
Radio lab did a story about this, they tested an old antibiotic recipe. http://www.radiolab.org/story/best-medicine/ http://www.radiolab.org/story/best-medicine/
crimsonalucard 10y ago
True. Unused traits that are not maintained with selection pressure begin accumulating random mutations. The eventual outcome is the complete disappearance of said trait. The downside to this is that the process of losing a trait is much more slower than gaining a trait. Think about it: Natural selection is a targeted process where by favored traits are directly selected and built up. Thus each generation gets a step closer towards a final selected outcome. On the other hand, losing a trait involves one waiting for random mutations to basically destroy the trait by random chance, no direct selection is involved. By probability the complete destruction of a trait not maintained under selection pressure will eventually occur given enough time. It is however basically comparing a blind folded dart game with a dart game that isn't blind folded. Hitting the center of the board in the blind folded game will take much longer than the other game but the center of the board will always eventually be hit given enough turns. We have seen experiments (and the recent amazing video) of bacteria evolving resistance to antibiotics. Does anyone know of any research that studies the length of time it takes for these bacteria to lose a trait?

by naz 10y ago

Very naive question: won't bacteria lose their resistance after a while? What if we cycle certain antibiotics on an annual basis? When we reintroduce them, they'll be more powerful. Right?

strebler 10y ago

I'm not sure, but that sounds like it might work. The real problem is: good luck getting all hospitals in the world to agree on a rotated schedule of which antibiotics to use / not use and when.

crimsonalucard 10y ago
We are not enforcing a rotating schedule but hospitals are already naturally rotating antibiotics in response to resistance. Once penicillin was lost we switched to another antibiotic. The problem is that we don't have enough classes of antibiotics restart the cycle. It takes way longer for bacteria to lose resistance than for bacteria to gain resistance.

simonbarker87 10y ago

I was chatting to doctor friend recently who has a masters in this area and he said that in theory yes but it would likely require the bacteria to have a reason to loose the mutation that caused the resistance in the first place so there is no guarantee.

crimsonalucard 10y ago
Your doctor friend is incorrect. Unused traits will be lost eventually through the accumulation of random mutations. In order for a trait to form and be stable in an organism, selection pressure must not just be applied... it must be maintained. This backwards process is actually observable. Many fish living in underground caves have lost their eyes through evolution. While eyes don't aid a fish in surviving in the dark, they certainly don't hinder the fish from surviving either... Yet cave fish have lost their eyes despite the lack of negative selection pressure.
- cariaso 10y ago
  > Many fish living in underground caves have lost their eyes through evolution. some have, yes. but in order to get the antibiotic benefit we're looking for, you'd need to have ALL fish having lost their eyes. That's a much higher bar. ( https://en.wikipedia.org/wiki/Blind_fish https://en.wikipedia.org/wiki/Blind_fish seems to be a reasonably comprhensive list ). We also need the antibiotics to be viable again in a reasonable timespan ( a decade or two?), in order to be useful -- not on the timescale that was involved in cavefish eye degeneration.
  - deleted 10y ago
    [deleted]
  - crimsonalucard 10y ago
    Bacteria mutate much quicker than fish. Generations of bacteria form within minutes. There is significant possibility in the viability of cycling antibiotics as bacteria lose resistance.
ocschwar 10y ago
The reason is there: bacteria have to be stingy in how much DNA they devote to anything.
- simonbarker87 10y ago
  Sounds reasonable, we were chatting about it briefly in a noisy pub so he would have glossed over details.

ocschwar 10y ago

If you can get the entire human race to match in lockstep with rotating antibiotics in and out, AND the array of antibiotics is large enough, then yes, that's exactly what would happen. The second part is in the works, constantly. The first part, however, is proving difficult.

cariaso 10y ago

> won't bacteria lose their resistance after a while? DNA is good at accumulating, and relatively poor at editing out. Some bacteria will lose resistance, just like your ancestors lost the ability to make Vitamin C. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145266/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145266/ but you only need one single bacteria to have not lost the ability. > What if we cycle certain antibiotics on an annual basis? it helps. We can also stack them, and use multiple attacks at the same time. which also helps. But it just delays the inevitable. > When we reintroduce them, they'll be more powerful. Right? the bacteria, yes. because they'll have accumulated defense mechanisms. Ultimately, I think we win this race, because we can intelligently and actively edit DNA.

mikeleung 10y ago

Radio lab did a story about this, they tested an old antibiotic recipe. http://www.radiolab.org/story/best-medicine/ http://www.radiolab.org/story/best-medicine/

crimsonalucard 10y ago

True. Unused traits that are not maintained with selection pressure begin accumulating random mutations. The eventual outcome is the complete disappearance of said trait. The downside to this is that the process of losing a trait is much more slower than gaining a trait. Think about it: Natural selection is a targeted process where by favored traits are directly selected and built up. Thus each generation gets a step closer towards a final selected outcome. On the other hand, losing a trait involves one waiting for random mutations to basically destroy the trait by random chance, no direct selection is involved. By probability the complete destruction of a trait not maintained under selection pressure will eventually occur given enough time. It is however basically comparing a blind folded dart game with a dart game that isn't blind folded. Hitting the center of the board in the blind folded game will take much longer than the other game but the center of the board will always eventually be hit given enough turns. We have seen experiments (and the recent amazing video) of bacteria evolving resistance to antibiotics. Does anyone know of any research that studies the length of time it takes for these bacteria to lose a trait?