[BurningFrog]

> Antibiotic resistant genes don't just disappear when we stop using antibiotics. They will remain in the gene pool effectively forever at low levels.

They very likely already were in the gene pool before we went on the antibiotics binge. Remember that our antibiotics were discovered in nature. They're used by other species to fight bacteria. Penicillin was used by moulds for unknown millions of years before we coopted it.

Since bacteria multiply within days or even hours, evolution works very fast in them. This is why they develop resistance within a few decades. How fast they would lose the resistance if we stopped is AFAIK not something we can know until we do it and see what happens.

[ansible]

They very likely already were in the gene pool before we went on the antibiotics binge. Remember that our antibiotics were discovered in nature. They're used by other species to fight bacteria. Penicillin was used by moulds for unknown millions of years before we coopted it.

Those antibiotic resistant genes likely weren't in pathogenic bacteria that affect humans though. And by improperly using antibiotics, we've created an environment where those genes cross species boundaries from where they originated.

[chrishynes]

What makes you think that pathogenic bacteria never contained antibiotic resistant genes before humans developed antibiotics? I've never seen a study that proves that antibiotic resistant genes were never in pathogenic bacteria.

Seems quite possible that antibiotic resistant genes were in all types of bacteria and the volume thereof responds to selection pressure.