I don't think zithromax will cut it when it comes to lyme and bartonella. I highly recommend Biaxin. IV zithromax is good but the oral zith will give you minimal results.
I recommend the following combo if you can tolerate it.
Biaxin, Bactrim, Doxycycline
Biaxin, Bactrim, Tetracycline
Roxithromycin, Bactrim, Tetracycline(my favorite)
Try Dr. Z's protocol...its a combo of things that includes the HH capsules---it worked wonders for my Bart....in fact I was off abx for almost 6 months and felt great while on Dr. Z's protocol...until I got a new tick bite a couple of weeks ago and had to go back on abx (deoxycycline)...bummer...but I am still taking Dr. Z's protocol along with the deoxy.
It truly works...at least it did for me.