Fungicide: Bio-Horror

The effect of the medication on him was unexpected. A single fungicide that should have caused some illness, but no lasting harm, killed him. The infestation that covered his skin was not affected. In fact, it grew rapidly, and we had to seal the lab facility and irradiate it repeatedly until the organism finally died. We are still trying to figure out how a fungus became so strongly resistant; we suspect it originates in one of the tropical zones where less reliable fungicides aren't banned. As you can imagine, this has caused no little panic. That the plant induces some chemical change, or perhaps inserts one chemical that will kill its host if a fungicide is introduced, is disastrous. That the fungus itself--

Inspiration: "effect"
Story Potential: Low.
Notes: Meh. Have seen versions of this a zillion times before, and don't have any fantastic new twist to make this stand out.