microbe vs micro-organism

microbe and micro-organism both are nouns.

Word	Noun	Adjective	Verb	Adverb
microbe	Yes	No	No	No
micro-organism	Yes	No	No	No

As nouns, micro-organism is a hypernym of microbe; that is, micro-organism is a word with a broader meaning than microbe:

microbe: a minute life form (especially a disease-causing bacterium); the term is not in technical use
micro-organism: any organism of microscopic size

Other hypernyms of microbe include microorganism.

microbe (noun)	micro-organism (noun)
a minute life form (especially a disease-causing bacterium); the term is not in technical use	any organism of microscopic size