One treatment which would probably be fairly effective to counteract an infection with an antibiotic-resistant bacterium which causes symptoms by secreting a toxin (such as pathogenic E. Coli which releases a Shiga toxin) is to induce an immune response (via immunoglobulin) against the toxin rather than the bacterium for the duration of the traditional symptomatic period. This should alleviate the symptoms as long as treatment is followed, and when the treatment ends the underlying infection will have been fought off by the immune system. Thus patients would be technically infected (and infectious) but would not exhibit symptoms caused by the toxin.

Here’s a study which demonstrates that it is possible to induce an immune response against the Shiga toxin in mice:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC321607/