Petman,
Speak with your BCG care team about your antibiotic. Some antibiotis, per my team, do require a BCG delay, some do not. Get a list if you can, of acceptable antibiotic for use during BCG - then show the list to any future provider who wishes to recommend an antibiotic.
My doc told me, "When you need the antibiotic to be healthy enough to fight the cancer, you take the most appropriate antibiotic AFTER the other doctor contacts me for a consultation".
Also see Dr. Lamm's comment at:
askdrlamm.bcgoncology.com/2005/12/antibiotics-and-bcg/
It is up to YOU to get your health care people talking with each other, to provide you with the best alternatives.
Best,
Jack