当人们乱用抗生素来治疗普通感冒时，当农民用抗生素来提高牲畜产量时，当制药公司将抗生素排入环境来降低生产成本时，本来应该被药品杀死的细菌就会获得免疫力。
When people recklessly use antibiotics to fight a common cold, when farmers use antibiotics to boost livestock productivity, or when pharmacological factories emit antibiotics into the environment to cut production costs, the bacteria that the drugs are designed to kill become immune.