キン

囗, 艾, 禾

艸

germ, fungus, bacteria

細菌(さいきん): bacillus; bacterium; germ
菌(きん): (1) fungus (2) germ; bacterium; bacillus
ばい菌(ばいきん): (1) germ; germs; bacteria; mold (mould) (2) something harmful (used figuratively); vermin