I've seen this movie. It does not end well.
Germs go into space, come back stronger:
It sounds like the plot for a scary B-movie: Germs go into space on a rocket and come back stronger and deadlier than ever. Except, it really happened. The germ: Salmonella, best known as a culprit of food poisoning. The trip: Space Shuttle STS-115, September 2006. The reason: Scientists wanted to see how space travel affects germs, so they took some along - carefully wrapped - for the ride. The result: Mice fed the space germs were three times more likely to get sick and died quicker than others fed identical germs that had remained behind on Earth.
So, inasmuch as you can't sterilize a person (well, you can, but they tend to be sort of unwell afterward), this has ramifications for space travel.
Or perhaps we're worrying too much. To borrow a phrase from Homer Simpson, I, for one, welcome our new bacterial overlords.