Definition of germ from the Star Trek Encyclopedia (4th ed., vol. 1, p. 303), "Any of a wide range of unicellular microorganisms, including many disease pathogens. Also called microbes. Germs are microscopic in size, but are among the most resilent organisms known to medical science, capable of survival in a broad range of environments, including in some cases the vacuum of space. By the 22nd century, more than 200 million space-dwelling microbes had been cataloged. One such microbe is a virulent disease pathogen called Polycocyx astris, which can survive in space, inside interstellar dust grains, for millions of years."