Nomenclature
Nomen = name
Cloture = one who speaks
So, nomenclature is a naming system. Bacteria, fungi, algae and protozoa are indentified by their genus and species. For example:
Streptococcus lactis
The name of the genus is always capitalized. The name of the species is never capitalized. This name is always highlighted, either by being underlined, or by being italicized. So, both of the following are correct:
Streptococcus lactis
Streptococcus lactis
If a microorganism is very well known, the genus may be abbreviated as the first letter in the genus name. For example, the following is correct.
S. lactis
Sometimes a subspecies and/or a bio variety is added. For example one may see:
Streptococcus lactis ssp lactis
Or,
Streptococcus lactis ssp lactis biovar diacetilactis
If the strain is known, it should be identified. For example:
Listeria monocytogenes ATCC 19116
Microorganisms of the same strain came from a single microorganism.
ATCC is a culture (or strain) collection. ATCC means American Type culture collection.