I think I just contaminated my whole growing area with Erwinia...

[Idril]

Hi, I'm new to this forum and to orchids. 2 weeks ago I rescued 2 orchids with severe root rot from somebody. I did a lot of research and things were going well, but a few days ago one of my plants got bacterial soft rot on one leaf. I cut that part off and that leaf is still fine, but today I found another leaf with a much bigger rot. I removed the whole leaf but I'm still not sure if I was able to stop spreading the disease. My other orchid is fine, besides the fact that it has no roots, but that's another story.
If these plants don't make it, I will want to buy a new, healthy plant. But I live in a small apartment and I only have a tiny place where I can grow plants, so the new orchid would have to live where my current ones live. Would it be in danger of soft rot because of the diseased plants even if I wait a few weeks in between plants? Other question is that I used to soak the one that got sick in the fish tank. So I guess now the water is contaminated? If I use that water on other plants that would be dangerous for them? How long can these bacteria live in water?