The time it takes for bacteria to develop resistance to new antibiotics has been as short as one year for penicillin V and as long as 30 years for vancomycin.

• 细菌产生对新抗生素的耐药所需时间不一，对青霉素V一年就有耐药了，而对万古霉素则长达30年才出现耐药。