The naming of bacteria is done according to the binomial system introduced by Carl Linnaeus. A bacterium has a genus name, which indicates the genus to which it belongs, and a species epithet. Epithets identify subordinate units within a genus. The genus name and the species epithet together form the scientific name, or the species name, of the bacterium. The name is formed using Latin or Latinized Greek words.
"International Code of Nomenclature of Bacteria" is the book that contains the strict international rules for the naming of bacteria. Before the acceptance of a proposed name of a species of bacteria, the rules require the publication of a scientific paper on the species and the approval of the paper by an international taxonomy committee. The scientific name is always written in italics. The naming of a bacterial genus is often simplified by the use of trivial names, which are not written in italics or with a capital first letter. Lactobacilli, staphylococci, mycobacteria, salmonella and streptococci are some trivial names. Never use the trivial name of a complete genus for referring to a specific bacterial species. It is sometimes essential to divide a bacterial species into subspecies. A subspecies epithet is used for introducing a subspecies. The epithet is indicated by writing ssp. or subsp. in front of it.