Please do not bathe your 2 week old kittens. I realize the comb method is difficult and yes, time consuming, but it is the ONLY way to SAFELY remove fleas from young kittens. Just keep working at it and it does work.
As for advice received in this, or for that matter, ANY Internet Forum, it needs to be said here that no online advice can replace direct veterinary intervention. If you suspect that your cat may be ill or if you are considering using unproven methods of home-treatment, please contact your vet immediately. You are welcome to look for advice in the health forums while waiting for that appointment, but never delay proper veterinary care waiting for Internet advice. Remember that cats, and especially kittens, are very adept in keeping pain to themselves and delaying treatment may cause irreversible damage.