Deb - It wasn't the abx. I did great for a week after the Z-pak but then all heck broke loose. Of course, I had the added stress of my Dad being ill and they had me up my gabapentin, which did not go well at all and caused more muscle spasms and tremors as well as other issues and just feeling so sick. This combination of the infection, stress, and increase in meds just prolonged everything for me. I get sinus infections at least once or twice a year (some years more) and I have never had any issues with the MS due to the Z-paks or Levaquin.
Sally - Can you say DENIAL?!?!

Don't worry, I say DENIED all the time. I just pretend I don't have it. It seems to work well for me until I overdo it and/or end up in a flare.