From here https://seachem.com/prime.php in the FAQ section
Prime does not prevent the bacteria growing, but it does interfere with the ammonia tester - there are a couple of FAQ's dealing with this on the same page.
Q: If Prime® is removing ammonia from the system, won’t that starve the beneficial bacteria?
A: Prime® does not remove ammonia, nitrite, or nitrate from the system. It simply binds with those compounds making them harmless to the inhabitants and still bioavailable to the beneficial bacteria.
Prime does not prevent the bacteria growing, but it does interfere with the ammonia tester - there are a couple of FAQ's dealing with this on the same page.