Method of spreading was never decided. Therefore this is impossible to argue. If nothing can stop this bacteria, how come there are survivors in the first place anyway? Because the bacteria doesn't spread absurdly fast (ie evacuate uninfected areas) or humankind found a method to hold it off temporarily. Isolation is a pretty good way of not getting things infected, which is exactly why method of spreading is crucial to know to even argue this.With other places offworld being colonized you won't just have isolated crews in ships. You will have huge barges carrying tons of bulk material, transporting animals/plants/food/etc, and colony ships. If absolutely nothing can stop this bacteria, it's going to spread anywhere humans will.
Temperature is an obvious one, but all kinds of conditions in space are different from those on earth. The easiest way to understand this is by... I don't know, comprehending the evolution theory?And I don't get why you say "the same thing that prevents humans from surviving in space." If you're telling me that space stops it, then woah, thanks for that revelation.
If you're telling me that something that no longer provides a barrier to humans in space (aka being able to terraform and move en masse offworld) will still provide a barrier to bacteria, then I have no idea how you support that position.