Which action does NOT help prevent the transfer of infection by a medication aide?

The action that does not help prevent the transfer of infection is the reuse of medicine cups that do not appear soiled. This practice can lead to cross-contamination, as previously used medicine cups may harbor microorganisms even if they don't visibly appear dirty. Reusing them poses a risk because it only takes a small number of pathogens to potentially cause infection, and some contaminants are not visible to the naked eye.

In contrast, maintaining hand hygiene through proper handwashing, cleaning medication trays after each use, and using tools like spoons or medicine cups to administer medications all significantly contribute to infection control. These practices create barriers to the spread of pathogens, ensuring a safer environment for both the medication aides and the residents they serve.