Has the rabbit had a culture test done of the bacteria in its nose? It may not be pasturella, other bacteria can cause snuffles, although pasturella is the most common as most rabbits carry it anyway.
If your rabbit has been in a rescue, been in boarding, been at a pet shop or at a breeders that has quite a few rabbits, then they most likely have pasturella anyway. It spreads extremely easily, as it is air-bourne, so any rabbit that is housed in the same airspace as many others will likely catch it from others that have no symptoms. It is also important to remember that it cannot be 'cured'. The symptoms and illness that it causes can be sorted, yes, but the bacteria can never be gotten rid of, and so even if the symptoms are treated, it can always reoccur later in life. It generally flares up in times of stress or when the immune system is suppressed in some way. The important thing to remember is that, whilst they may carry the bacteria, most rabbits will never get ill from it, as it is not triggered until the immune system is compromised in some way.
I have two rabbits, Barney has recurring snuffles, and seems to never be rid of symptoms completely, he has bisolvon (thins mucus) about half of the time (used to be daily) and a few weeks of echinacea (immune support herb) when he needs it, but rarely needs antibiotics these days. Annabella, on the other hand, had it once, had a course of antibiotics, and it went, but then she is and has always been a very healthy bunny.
It is not true that she will definitely have to live indoors, Barney seems to do much better outdoors, and I believe that is not uncommon.
