Yes please don't retreat the kittens again, it could be deadly to them.
You are still seeing fleas on the kittens. Perfectly normal. You see once the fleas jump on and bite the kittens it takes them about 24 hours to die completely, although the medicine should start killing them almost immediately.
Also once the fleas bite the animal they start laying eggs. One female flea can lay up to 50 eggs a day. So chances are some of the fleas and their eggs were able to get into your house, carpeting, etc. and even though you bathed your kittens, those fleas are probably the ones you are now seeing on the kittens.
Get some Diatomaceous Earth by Perma Guard, the food grade
type, which is also edible by humans and animals. Farmers use it in their grain stock to kill pests. This "Earth" is not a chemical
. It is mechanical. It is ground up fresh water diatoms. See here It explains what the diatomaceous earth is: [url="http://http://www.shadowridgedonkeys.com/perma_guard_what.htm
Also here is a link to the Perma Guard site: [url="http://perma-guard.com/distributors.htm[/URL
Once again, make sure to get the food grade one!
Hope this helps!