The mites are bad for your cultures.
Try keeping you cultures under a light, as the mites hate it.
As for getting rid of the mites, You have a challenge ahead of you.
You may try flooding the cultures (springtails float) and see if the mite float. I would then spoon the springtails out and watch for mites as you get the springtails. You may get some might eggs, you may not...
Yup, as Ben stated earlier, mites are definitely bad for your culture. I've had a couple of very nicely established cultures go completely bad in a matter of a couple of weeks due to mites. I'd suggest salvaging some of the adult springtails in the way Ben described, and start some new cultures.
I had a very nice culture in shobox going all last year and last winter I noticed the numbers slowly going down in it.I took a closer look and it was filled with the little mites like you have in your pic.I took the whole culture out and let them enjoy a -10 night in January.I caught about 10 springtails out of my vittatus's tank and now have a couple good cultures going now.With Ben's advice I have cheapo undercabinet flour.light over them and have had no problems since with the mites. I hope you get them cleared up.I was bummed when I lost them all but I didn't have any froglets at the time that were young enough to need them so I was lucky.