I think a factor of importance is how much selective pressure there is that could lead to their creation. The sporadic and fairly arbitrary use in humans doesn&#x27;t create a selective pressure strong enough to create these superbugs in meaningful amounts and have them survive.<p>When used en masse in large, concentrated populations, you&#x27;re statistically much more likely to bring these superbugs into existence, and have them survive. After all, an infected human is fairly isolated. But Stick an infected chicken in a hen and you&#x27;ve got some trouble on your hands.