Question: How can a drug target bacteria/disease/infection?

Andrew Scott answered on 25 Jun 2015:

I don’t have experience with targeting bacteria or viruses. I do know that we can target drugs to certain cells by making the drug look like something that attaches to the cell or can pass into the cell. In MRI we sometimes use this by combining the drug with something we can see in the MRI pictures. For example, we might know that the plaques that build up on the arteries in our hearts and cause heart attacks gather up lots of a certain type of fat. We can sometimes stick a chemical that we can see in the MRI pictures to the fat. If we inject this drug-chemical combination we might be able to see where the plaques are. This is known as molecular imaging.

You can see how we might swap the chemical we see in the MRI pictures for something that kills the plaque or bacteria.