If you are still getting a positive babesia test result after many many months of mepron/zith, i think it is time to find a more effective solution to your babesia. I don't know too many that have beat babesia with mepron/zith. There are some that say it is gone but most of the strains of babesia cannot be fully eradicated with this mix.
Ask you LLMD about Primaquine/chloroquine/biaxin. Chloroquine is only taken for the first 2 weeks and primaquine is taken for the duration(months). I know of quite a few who have beat babesia with this mix. And your insurance company won't get pissed off because this combo is very cheap. It is also better to combine this mix with biaxin.
There are other more effective/cheap babesia options such as Clindamycin/quinine but i think this option is last resort. You should also consider adding artmenisin to the babesia treatment. Some have even used tafenoquine and alinia for babesia.
It has been said many times before. "you can't make lyme go away until you tackle babesia"
But if you believe that IV abx is the route and your babesia infection is gone, then i'd say, disregard what i mentioned.