My daughter had the same situation this winter. She was put on Amox. twice, the Z-Pack, and another antibiotic that I don't remember the name. Then we went to an ENT and he prescribed another antibiotic but this time didn't do a Strep test. Instead he did a full culture and let it culture for 3-4 days. It actually ended up going over the weekend and when I got a call the following Monday morning, she had some sort of bacterial infection. We kept her on the antibiotic (which unfortunately I don't recall that one either, sorry) and that did finally take care of the infection. She did have her tonsils taken out about 10 days or so after she completed the last antibiotic. When you go to the ENT make sure to ask the to do a full throat culture on him. All I remember was that the bacterial infection started with a H. The name for some reason just never stuck in my head, even after just talking with him. Unfortunately, they can not take the tonsils out if there is an infection, bacterial or viral, since they would run the risk of spreading it. I hope this helps. I feel for your son. It was no fun for my daughter. But now, after she had her tonsils removed and healed from it. She told me that she feels better then she did in a long time. And it wasn't just because her throat didn't hurt. She was talking her whole physical being. Si I think that whatever this bacterial infection was, it was dragging her down too. Good luck and I hope this helped some.