Sorry james I went back and added some this and that, haha . You know how that goes..

They added the target bacterias ability to communicate and detect it's own species to the e.coli. Then they also gave the e.coli the ability to release the same but tweaked up bacterial toxins that the target bacteria releases. So they put the e.coli in the host, the e.coli detects the target bacteria, communicates to each other and send out the tweaked toxins to kill the target, but it also fills with the toxins and kills itself. And the Host will be free from both. make sense ? I think that is the jist..

Different than cancer, because the host will be free.