Key points from article :
65% rise in worldwide consumption of the drugs from 2000 to 2015.
Public health experts call for fresh strategies to rein in excessive use.
Drug-resistant infections kill more than half a million people a year worldwide.
Poorer nations still use antibiotics far less intensely than richer ones.
Colistin reintroduced despite being abandoned in the 1970s due to toxicity.
The study was published in Proceedings of the National Academy of Sciences.
