T.D.
Kidney reflux is a condition generally found in young children where urine is allowed to pass up into the ureters during urination. This allows bacteria present in urine proliferate, and sometimes pass up into the kidneys. As you can well imagine, this condition can cause some serious problems. However, this is rarely the case. Kidney reflux is usually outgrown by school age. Basically, your baby girl has a valve in her bladder that is either too small or too weak to do its job. As she grows, the valve will also grow and get stronger, and eventually fix the problem. Until that happens, your pediatrician (or possibly a urologist) should keep an eye on the situation, and treat the complications. It sounds like they're doing a good job of this by placing her on a maintenance dose of antibiotics.
If your daughter gets older, and the problem doesn't resolve itself or becomes severe, there is a surgical fix. A surgeon will go in through key hole surgery, sever the ureter, and reattach it at a slightly different angle. This is not very likely to happen because as I've said, she'll most likely outgrow the problem.
**Things to keep in mind:
Constant low doses of antibiotics can cause antibiotic resistant illnesses. If your daughter gets sick, make sure that it is well know that she's been on low dose antibiotics, how long, which antibiotic, and what dose. This is important!
If you daughter starts to have pain with urination, flank pain, fever, or general malaise, have her seen by the doctor. Don't assume that it's a bug. She's at higher risk for serious infection until this gets sorted out.
Make some sort of deal with your pediatrician for how to deal with nighttime and weekend illnesses. It's better to make arrangements now and never need them, than sit in an ER or urgent care for hours when your pediatrician could deal with it in minutes.
Good luck. I hope this helps