superbug

noun

1. (informal)A strain of bacteria that is resistant to many antibiotics (e.g., MDR, XDR).

   “But now we’re seeing increasing numbers of superbugs that survive antibiotics. One of the best-known —[is] MRSA, a kind of staph infection [that]— kills about 18,000 Americans annually. That’s more than die of AIDS.”

2. (informal)Any pathogen resistant to many, even all, of the biocides or other agents used to treat similar pathogens.
3. (US)An invasive insect, Bemisia tabaci, that is a major pest of vegetable crops, both directly and as a virus vector.