Germicidal fluorescent light bulbs for hospitals, food service facilities anywhere killing bacteria is important.

As with all fluorescent bulbs, they rely on ballasts inside of the fixtures in order to make them work. Ballasts are available from Universal, Osram Sylvania, among others. Almost all fixtures for these bulbs come with ballasts already mounted and wired. The ballast is important because it is specific for each type of lamp.  You can't change from one type of fluorescent to another without changing the ballast in most cases.  Most of the time the ballast and the lamp are matched electrically and so it's good to make sure the ballast you have is the right one for the lamp you choose. The germicidal fluorescent light bulbs typically operates on a magnetic ballast which is less efficient than it's electronic counterpart, but that's beginning to change.  Look for this lamp commonly used in a shielded fixture out of the way of anyone's field of view.  The reason for that is that germicidal light bulbs can cause eye damage, that's why they're always used in an indirect lighting fixture.