https://www.dailymail.co.uk/sciencetech/article-13336239/NASA-mutant-bacteria-international-space-station.html
Researchers discovered 13 strains of the bacteria, called Enterobacter bugandensis that is linked to blood infections on the International Space Station (ISS), which could compromise the health of astronauts on board.
The extreme environment on the ISS like higher carbon dioxide levels forced the bacteria to mutate, and when exposed to microgravity, the bacteria can acquire a resistance to antibiotics