Aeolus451 on 10 December 2014
I watched some show explaining that someone accidentally sneezed on a space shuttle as it was being built and it went into space then came back to earth. That's when they discovered the stuff on it. They discovered the microbes survived re-entry and everything space could throw at it but also mutated into a more deadly strain. I can't remember what the show was called or much about it. I tried to found something about it and but couldn't. I did find some relevant info about your question though.
http://www.popsci.com/technology/article/2010-08/bacteria-survive-553-day-exposure-exterior-iss
http://www.scientificamerican.com/article/bacteria-discovered-spacecraft-clean-rooms/
http://www.npr.org/templates/story/story.php?storyId=14653292
