Trimethoprim for IBS??????

I received an email yesterday from an IBSer whose doctor prescribed trimethoprim as a treatment for their IBS symptoms. I had never heard of this medication, so I did a little digging. I could find no research related to trimethoprim for IBS. What I did discover is that trimethoprim is an antibiotic generally used to treat urinary tract infections. I do know that there is some research that suggests positive results of the antibiotics Rifaximin and Neomycin for IBS. If anyone has any further information on trimethoprim I would love to hear about it. Please post to the IBS discussion forum.