I was taking Remicade for about a year with good results. In between my 8 week infusion schedule, I got the flu really bad which ended up in pneumonia. I went to the hospital and, despite my insistence that they not do it, they gave me antibiotics. I got better in about 3 days however my UC flared and I was right back where I started. I blame this on the antibiotics.
Long story short. I continued with my infusions but noticed that the improvement with my UC flare was only working for about 3 weeks after the infusion. My doc did a blood test and found that I had developed antibodies to Remicade. I blame this on the antibiotics.
This is not a really good answer to your question, but if I were you, I would stay away from antibiotics and I can't imagine that a short delay of your infusion would cause any harm.