The only types of filter that I've heard of that really has problems with the bacteria dying off are biowheels (because they get stuck fairly regularly and part of the wheel dries out for a long time) and fluidized bed filters (because supposedly the setup goes anoxic and dies quickly when the pump goes off, which sounds kinda fishy to me, but there ya go.)
I know it's anecdotal, but I built a canister filter and had some ceramic filter media in it. I got it cycled then it started leaking (a homemade canister leaking? NEVER!) and I took the lid off and drained most of the water. The wet media and water went in some tupperware on the counter. When I tried restarting it several days later, I wanted to get it cycled quickly so I started it in a bucket with ammonia. The bacteria hadn't died off in that time and it was able to clear the bucket in a day (could have been much less but I didn't bother checking before then.) It had never dried out and the container was open to the air the entire time.