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?
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/ 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.
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?
The second part is in the works, constantly. The first part, however, is proving difficult.
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.
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 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.