an antibiotic in the pharmaceutical sense

I seem to recall that, by definition, an "antibiotic" is a substance that inhibits the growth of bacteria, and which is derived from or elaborated by another biological organism. Just killing germs isn't enough.

That makes penicillin (from the Penicillium notatum bread mold) and streptomycin (from Stretomyces species) antibiotics, but all the Sulfa drugs (sulfanilamide, etc. - nothing to to with the element sulfur, really), being derived from the chemist's lab rather than the plant kingdom, aren't. Germicides, yes; useful, certainly; "antibiotics", strictly speaking, no.

Comment?