S. typhimurium has proved a difficult target for science

The bacteria were almost three times as likely to kill infected mice compared with standard samples held on Earth.

The study, presented in Proceedings of the National Academy of Sciences, is said to have important implications for astronauts going to the Moon or Mars.

S. typhimurium is one of the more difficult food bugs to treat with antibiotics, and long spaceflight missions would need to take care that good hygiene standards were maintained.

"Wherever humans go, microbes go; you can't sterilise 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," Cheryl Nickerson, from the Center for Infectious Diseases and Vaccinology at Arizona State University, US, told the Associated Press.