Preservation of Antibiotics for Medical Treatment Act of 2017 This bill amends the Federal Food, Drug, and Cosmetic Act to require an applicant for approval of a new animal drug that is a medically important antimicrobial to demonstrate that there is a reasonable certainty of no harm to human health from antimicrobial resistance attributable to the nontherapeutic use of the drug. Medically important antimicrobials are drugs intended for use in food-producing animals that contain: (1) specified antibiotics, or (2) certain drugs on the World Health Organization’s list of critically important antimicrobials. Two years after enactment of this bill, the Food and Drug Administration (FDA) must withdraw approval of a drug's nontherapeutic use in food-producing animals unless the FDA makes a determination that, based on the application holder's demonstration or an FDA risk analysis, there is a reasonable certainty of no harm to human health from antimicrobial resistance attributable to nontherapeutic use. The FDA must rescind an exemption for investigational use of, or approval of a new drug application for, a medically important antimicrobial for its nontherapeutic use in food-producing animals two years after the exemption is granted or the application for approval is submitted unless there is a reasonable certainty of no harm to human health from antimicrobial resistance attributable to nontherapeutic use. A medically important antimicrobial cannot be administered (including through animal feed) to a food-producing animal for disease control unless there is a significant risk that a disease or infection present on the premises will be transmitted to the animal.