5 ms·

> without inducing antibiotic resistance Isn't that a way of saying "no bacteria can ever adapt to this method of killing them"? Won't at least 0.1% of them fi

> without inducing antibiotic resistance Isn't that a way of saying "no bacteria can ever adapt to this method of killing them"? Won't at least 0.1% of them find a way to survive, and gradually adapt to this as well?

kulahan 3y ago
>Cationic polymers are a promising class of bioactive agents, which trigger bacterial cell death through physical disruption of their membranes. It sounds like it would be equivalent to humans evolving bulletproof skin. (quote is from their original paper which is linked in the article)
- teppic 3y ago
  > It sounds like it would be equivalent to humans evolving bulletproof skin. You don’t need bulletproof skin if you can avoid being shot.
- roughly 3y ago
  Yeah, and I think that's where the tension is: - bacteria evolve much, much faster and over a wider range of capabilities than you'd think, so this is possible - hell, even probable - given the range of extremophiles we've seen - for practical purposes, though, every adaptation comes with a cost, though, and the bacteria are not currently immune to this treatment because whatever they use for their membranes in absence of this threat is cheaper than something not vulnerable to this, which means this adaptation is disadvantaged where the polymers are not present - the amount of time a bacterial colony has to evolve a response is basically limited to the amount of time it takes for a dose to kill the entire colony, which may not be long enough to reach a solution given the distance the genome would have to travel - but, re: point 1, it's not guaranteed forever, which is why no scientist will say so - but the media sure will, and for practical purposes may not be wrong
  - kulahan 3y ago
    The scientist in the article is quoted as saying that bacteria do not appear to develop resistance to this.
    - hedora 3y ago
      That’s been true of pretty much every antibiotic at launch.
xaellison 3y ago
"bacteria do not seem to develop resistance" - Dr. Quentin Michaudel The press release is (predictably) more cavalier in its claim! All this release says is that the polymers "[disrupt] the membrane of these microorganisms". At that level of detail, penicillin works similarly, and is vulnerable to resistance. I'd love to know more detail about how this is a different kind of disruption.
lainga 3y ago
I thought there was a sort of "iron triangle" between antibiotics and phage therapy where bacteria couldn't maintain resistance to both. But OTOH phage therapy is several decades old and still rarely used
- corethree 3y ago
  It's well developed and used by doctors in Russia I hear.
bawolff 3y ago
I dont see why that would be true. The liklihood of adaption depends on the details of the method. Not everything is easily adapted out of. Humans have been shooting each other with guns, and before that bows and arrows for a long time, and yet evolution hasn't provided us with fire-arm resitance yet.
- BobaFloutist 3y ago
  Humans take a much much longer time to evolve than bacteria (and much longer than we've been shooting each other), and your average human doesn't die to gunfire before they get to reproduce. I'm sure if you put humans in an environment with a major chance of dying to gunfire before they reproduced for hundreds of millions of years or whatever we'd start to develop thicker bones or something - or just earlier and faster reproduction.
- acover 3y ago
  Another example: boiling kills most bacteria, very few have evolved to survive it.
- arrowleaf 3y ago
  I'm assuming the intended application of this is to kill bacteria colonizing a biological host. In order for that to work, the treatment needs to be selective in what it kills. If human/animal/plant cells have any mechanism to avoid being killed by the antibiotic, eventually the bacteria will adapt them.

kulahan 3y ago

>Cationic polymers are a promising class of bioactive agents, which trigger bacterial cell death through physical disruption of their membranes. It sounds like it would be equivalent to humans evolving bulletproof skin. (quote is from their original paper which is linked in the article)

teppic 3y ago
> It sounds like it would be equivalent to humans evolving bulletproof skin. You don’t need bulletproof skin if you can avoid being shot.
roughly 3y ago
Yeah, and I think that's where the tension is: - bacteria evolve much, much faster and over a wider range of capabilities than you'd think, so this is possible - hell, even probable - given the range of extremophiles we've seen - for practical purposes, though, every adaptation comes with a cost, though, and the bacteria are not currently immune to this treatment because whatever they use for their membranes in absence of this threat is cheaper than something not vulnerable to this, which means this adaptation is disadvantaged where the polymers are not present - the amount of time a bacterial colony has to evolve a response is basically limited to the amount of time it takes for a dose to kill the entire colony, which may not be long enough to reach a solution given the distance the genome would have to travel - but, re: point 1, it's not guaranteed forever, which is why no scientist will say so - but the media sure will, and for practical purposes may not be wrong
- kulahan 3y ago
  The scientist in the article is quoted as saying that bacteria do not appear to develop resistance to this.
  - hedora 3y ago
    That’s been true of pretty much every antibiotic at launch.

xaellison 3y ago

"bacteria do not seem to develop resistance" - Dr. Quentin Michaudel The press release is (predictably) more cavalier in its claim! All this release says is that the polymers "[disrupt] the membrane of these microorganisms". At that level of detail, penicillin works similarly, and is vulnerable to resistance. I'd love to know more detail about how this is a different kind of disruption.

lainga 3y ago

I thought there was a sort of "iron triangle" between antibiotics and phage therapy where bacteria couldn't maintain resistance to both. But OTOH phage therapy is several decades old and still rarely used

corethree 3y ago
It's well developed and used by doctors in Russia I hear.

bawolff 3y ago

I dont see why that would be true. The liklihood of adaption depends on the details of the method. Not everything is easily adapted out of. Humans have been shooting each other with guns, and before that bows and arrows for a long time, and yet evolution hasn't provided us with fire-arm resitance yet.

BobaFloutist 3y ago
Humans take a much much longer time to evolve than bacteria (and much longer than we've been shooting each other), and your average human doesn't die to gunfire before they get to reproduce. I'm sure if you put humans in an environment with a major chance of dying to gunfire before they reproduced for hundreds of millions of years or whatever we'd start to develop thicker bones or something - or just earlier and faster reproduction.
acover 3y ago
Another example: boiling kills most bacteria, very few have evolved to survive it.
arrowleaf 3y ago
I'm assuming the intended application of this is to kill bacteria colonizing a biological host. In order for that to work, the treatment needs to be selective in what it kills. If human/animal/plant cells have any mechanism to avoid being killed by the antibiotic, eventually the bacteria will adapt them.