Medical staff are notorious for not washing their hands enough.
Today’s invention is intended to encourage handwashing and thus to protect patients.
Every door handle in a hospital or clinic would be replaced with one which exudes a small amount of harmless chemical when the door is operated. This chemical would smell dreadful (I leave that part to your imagination).
Patients would be quick to complain about being treated by medical staff with smelly hands and thus doctors and nurses (and patients too) would have to keep washing -thus frequently cleaning off the smell as well as the toxic bugs.