[cyberax]

> those strains will gradually lose their resistance once no longer exposed to antibiotics

No, they do not. Bacteria eventually optimize and streamline genes that confer resistance, and they stay around basically forever in a small reservoir of bacteria. So once you start using the antibiotics again, these streamlined genes almost immediately reappear.

[kijin]

Another problem is that there is scarcely any place left in the world where disease-causing bacteria can survive for long without being exposed to some amount of antibiotics. Modern farms and hospitals are contaminating the entire environment with antibiotics. So there's always a bit of selection pressure that favors those with resistance genes.

A few years ago, a North Korean soldier was shot several times as he dashed across the border in plain sight of other soldiers. After he arrived in the South, the surgeon who treated his wounds reported an unusually high effectiveness of antibiotics administered to him. The bacteria on his skin and in his guts had been exposed to little to no antibiotics before.

[M95D]

Very interesting story! Do you have a link?

[kijin]

The soldier is https://en.wikipedia.org/wiki/Oh_Chong-song but the Western media doesn't seem to talk about antibiotic resistance. It might have been an informal mention in the domestic media, not part of the official report. (The surgeon who treated him is a kind of celebrity in Korea, so whatever he says in lectures and interviews tends to get repeated in the news.)