A related thread of research uses bacteriocins as negative selective systems in cloning.

http://nar.oxfordjournals.org/content/early/2015/03/23/nar.g...

This is a huge and loosely explored space, but it is really important for basic research because the current selective markers (which are basically broad spectrum antibiotics) often have low efficiency. I feel silly for having read about this work and not made the connection to medicine!