The researchers placed identical strains of salmonella in containers and sent one into space aboard the shuttle, while the second was kept on Earth, under similar temperature conditions to the one in space.
After the shuttle returned, mice were given varying oral doses of the salmonella and then were watched.
After 25 days, 40% of the mice given the Earth-bound salmonella were still alive, compared with just 10% of those dosed with the germs from space. And the researchers found it took about one-third as much of the space germs to kill half the mice, compared with the germs that had been on Earth.
The researchers found 167 genes had changed in the salmonella that went to space.
Update: Uh, oh. "“For the first time ever, animals are now being exposed to an unmitigated space environment, with both vacuum conditions and cosmic radiation." Read more about tardigrades being exposed to space here and here.