A ScienceDaily article says that the protein in teardrops can kill bacteria.
But how does it reach the bacteria?
I am not sure I understand your question.
According to the article you mention the proteins in teardrops kill the bacteria which are invading the eye (e.g. also present in the teardrops):
EDIT: These proteins are enzymes called lysozymes. Those are free-flowing proteins of the human tears. These proteins are actively produces in the lacrimal glands and actively secreted into the lacrimal liquid.