you can do a mild bleach dip on plants to keep from transferring any bacteria. it's not as common as you would think. normally attacks guppies and labrynth fish, like gouramis and bettas. and most likely, if the tanks have been broken down and the items have dried out, the bacteria died. most bacteria have certain requirements to survive and thrive. not all, but most. like carlos said, boiling or baking will kill it. i wouldn't be concerned about the soil your plants are in. if you have ever had a cut or sore on your fingers or hand while handling your plants or soil, you would already know by now if the bacteria was present.