Gabe...By now you know that sulfa drugs are not MG-friendly. Levaquin is a safer antibiotic for folks with MG. My neuro told me that the cephalosporins and quinalones are the [more MG friendly] antibiotics. Levaquin treats UT infections, respiratory infections and sinusitis.
If you go to the MGFA site,
http://www.myasthenia.org/mgfa/, there is a list of contraindicated drugs that MG'ers must be careful of or avoid altogether, depending upon the drug and your individual reaction to them.