This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. of, relating to, or caused by microbes or microorganisms

adj. Of, pertaining to, or caused by, microbes

Of or pertaining to microbes; caused by or due to microbes. Also microbal.

adj. of or involving or caused by or being microbes

"Finally, check to make sure that your policy doesn't include what they call a microbial-matter exclusion."

microbian   

bacterial    fungal    exogenous    endogenous    antigenic    antimicrobial    oxidative    intracellular    leukocyte    nucleic