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 bacteria: Salmonella, best known as a culprit of food poisoning (in horses it can cause debilitating–and even deadly–diarrhea). 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.

“Wherever humans go, microbes go; you can’t sterilize humans. Wherever we go, under the oceans or orbiting the earth, the microbes go with us, and it’s important that we understand … how they’re going to change,” explained Cheryl Nickerson, PhD, an associate professor at the Center for Infectious Diseases and Vaccinology at Arizona State University.

Nickerson added, in a telephone interview, that learning more about changes in germs has the potential to lead to novel new countermeasures for infectious disease