Basically, the massive use of antibiotics around the world has imposed such large selection pressure on bacteria that resistance is now a problem, because we've now selected for just the resistant bacteria.
简单的说，世界范围内的 抗生素滥用 已经导致其对很多细菌不起作用了， 抗药性已经成为了一个问题， 因为我们如今所针对的细菌 恰恰都具备了抗药性。