Exactly. And apparently one very big misuse is the widespread use of antibiotics in non-infected domestic animals - which can lead to resistance in humans eating that meat. As I understand it, they are peppered with anti biotics to survive the conditions they live under.
Hm - revenge of illtreated animals?? Would be justice, actually.
Another is apparently overuse of antibiotics, because people have to hurry back to work and do not have time to wait for their own system to deal with it.
And a third is, as Deniseri mentions, large numbers of people in cities, and infected people in hospitals.