Was giving one of my children a rectal temp. before i had a chance to wash it, his bro took thermometer and put it up nose. worry about e. coli?

No: E. Coli is everywhere and his brother has this organism in his colon as well. Highly unlikely that anything negative will result from this.

It happens: Kids do crazy things sometimes. Something like this comes along that you never even though could happen in your home. Our skin/mucosal linings are there to protect us. In the event of redness in or around the nose and/or discharge, have your pediatrician take a look. Otherwise, remind him to never do that again. Take a deep breath, he'll be ok.