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...
Hope this helps,