Reptile mite and rodent mites are to different things. However reptile mites can live for a short time and even feed for a time on mammals. For your snake to catch reptile mites from a feeder is possiable but that prey item would have had to come in contact or be in close distance to reptiles with mites.
Here is a good read for anyone interested. http://vpi.com/publications/the_life...of_snake_mites