3 ms·

Bacteria are minimalist (http://www.sciencedirect.com/science/article/pii/S0092867402006657 http://www.sciencedirect.com/science/article/pii/S0092867402...) whi

by yourkin 10y ago

Bacteria are minimalist (http://www.sciencedirect.com/science/article/pii/S0092867402006657 http://www.sciencedirect.com/science/article/pii/S0092867402...) which tends to amplify the use it or loose it evolutionary principle. There's a certain cost to keeping a "feature" in an organism that small with a high rate of mutation and adaptability. "Strains of bacterial pathogens that have acquired mutations conferring antibiotic resistance often have a lower growth rate and are less invasive or transmissible initially than their susceptible counterparts." http://aac.asm.org/content/54/5/2085.full http://aac.asm.org/content/54/5/2085.full If evolutionary logic holds (and there's little doubt about that, though research on the rate of resistance lose with time varies), switching to new classes of antibiotics and not using old ones until resistance to them de-evolves is a viable strategy.

aab0 10y ago
But how long is that going to take? Resistance has very high fitness in the presence of humans using antibiotics (avoiding death); resistance has very small negative fitness in the absence of humans using antibiotics (saving a tiny bit on metabolism). However long it took to evolve resistance, it'll take many times longer to de-evolve it. And given randomness, a tremendous number of copies of the resistance genes will hang around anyway so the resistance will come back even faster the second time.
- riffraff 10y ago
  I imagine antibiotic resistance is not just an on/off switch in a vacuum, i.e. a different chemical surface might interact differently with a drug but also have some adverse effect, so losing the resistance would be advantageous.
- fweespeech 10y ago
  http://articles.courant.com/2011-01-11/health/hc-weir-antibiotic-yale-0112-20110111_1_antimicrobial-chemotherapy-antibiotics-edward-septimus http://articles.courant.com/2011-01-11/health/hc-weir-antibi... Too long. You can get significant mileage out of a 3 year ban but resistance will return very quickly afterwards. You'd need to wait decades to truly reset the clock. > After three years of banning the use of that antibiotic, the resistance of the bacteria dropped significantly. But because there were resisitant strains that persisted right through the end of the study in 2008, it was likely that the resistance would surge once again if the antibiotic were reintroduced. To safely reintroduce the antibiotic, Townsend said, you have to kill off all the pathogens. > Considering how important antibiotics have become to human health — from the treatment of strep throat to MRSA to tuberculosis — Townsend says a 45-year ban on most antibiotics would be impractical. Doctors estimate it takes about that long for the resistance to disappear.
paulmd 10y ago
There's tremendous political problems with just "not using them" - we've done shelving before, usually with drugs that have unfavorable characteristics. Colistin is one example, it was shelved because it's fairly nephrotoxic, and today it's one of the last-resort antibiotics. The problem is China loves to pump their livestock full of it to boost production, and now we're starting to see bacteria strains that are resistant to it. http://phenomena.nationalgeographic.com/2015/11/21/mcr-gene-colistin/ http://phenomena.nationalgeographic.com/2015/11/21/mcr-gene-... The WHO simply do not have any teeth to enforce shelving, and it's probably going to take a major health crisis before it's even on the table.
- zasz 10y ago
  Not just China, the US is also a huge culprit. (http://www.cdc.gov/narms/resources/threats.html http://www.cdc.gov/narms/resources/threats.html)
- nikanj 10y ago
  From an outsider perspective, the US also loves to pump their livestock full of antibiotics to boost production.
  - paulmd 10y ago
    The foreign use of drugs-of-last-resort is what's specifically concerning, and what raises the questions of the WHO's ability to coordinate and enforce shelving. The use of common antibiotics isn't good, by any means, but last-defense drugs being used is far worse.
- yourkin 10y ago
  A colony of pig microbes getting resistant somewhere in China to an antibiotic rarely used to treat people, might not be that big of a threat if spreading of the bacteria is contained. It even might be that most drug-resistant colonies just die out locally. How many human cases have been registered of Colistin resistant diseases?
  - 10y ago

by yourkin 10y ago

aab0 10y ago

But how long is that going to take? Resistance has very high fitness in the presence of humans using antibiotics (avoiding death); resistance has very small negative fitness in the absence of humans using antibiotics (saving a tiny bit on metabolism). However long it took to evolve resistance, it'll take many times longer to de-evolve it. And given randomness, a tremendous number of copies of the resistance genes will hang around anyway so the resistance will come back even faster the second time.

riffraff 10y ago
I imagine antibiotic resistance is not just an on/off switch in a vacuum, i.e. a different chemical surface might interact differently with a drug but also have some adverse effect, so losing the resistance would be advantageous.
fweespeech 10y ago
http://articles.courant.com/2011-01-11/health/hc-weir-antibiotic-yale-0112-20110111_1_antimicrobial-chemotherapy-antibiotics-edward-septimus http://articles.courant.com/2011-01-11/health/hc-weir-antibi... Too long. You can get significant mileage out of a 3 year ban but resistance will return very quickly afterwards. You'd need to wait decades to truly reset the clock. > After three years of banning the use of that antibiotic, the resistance of the bacteria dropped significantly. But because there were resisitant strains that persisted right through the end of the study in 2008, it was likely that the resistance would surge once again if the antibiotic were reintroduced. To safely reintroduce the antibiotic, Townsend said, you have to kill off all the pathogens. > Considering how important antibiotics have become to human health — from the treatment of strep throat to MRSA to tuberculosis — Townsend says a 45-year ban on most antibiotics would be impractical. Doctors estimate it takes about that long for the resistance to disappear.

paulmd 10y ago

There's tremendous political problems with just "not using them" - we've done shelving before, usually with drugs that have unfavorable characteristics. Colistin is one example, it was shelved because it's fairly nephrotoxic, and today it's one of the last-resort antibiotics. The problem is China loves to pump their livestock full of it to boost production, and now we're starting to see bacteria strains that are resistant to it. http://phenomena.nationalgeographic.com/2015/11/21/mcr-gene-colistin/ http://phenomena.nationalgeographic.com/2015/11/21/mcr-gene-... The WHO simply do not have any teeth to enforce shelving, and it's probably going to take a major health crisis before it's even on the table.

zasz 10y ago
Not just China, the US is also a huge culprit. (http://www.cdc.gov/narms/resources/threats.html http://www.cdc.gov/narms/resources/threats.html)
nikanj 10y ago
From an outsider perspective, the US also loves to pump their livestock full of antibiotics to boost production.
- paulmd 10y ago
  The foreign use of drugs-of-last-resort is what's specifically concerning, and what raises the questions of the WHO's ability to coordinate and enforce shelving. The use of common antibiotics isn't good, by any means, but last-defense drugs being used is far worse.
yourkin 10y ago
A colony of pig microbes getting resistant somewhere in China to an antibiotic rarely used to treat people, might not be that big of a threat if spreading of the bacteria is contained. It even might be that most drug-resistant colonies just die out locally. How many human cases have been registered of Colistin resistant diseases?
- 10y ago