A person's name (often a microbiologist), a geographical place, a phenotypic trait (growth state, color, biochemical properties,) or any other source might be used to create the name.
For example, the genus Escherichia coli is named after Theodor Escherich, who isolated it, and the species epithet name refers to the colon, which was the source of its isolation.
Staphylococcus aureus is another example. Its species was called by the golden color of its colonies, and its genus was named from its phenotypic traits (the grapelike coccus).
Bacteria are categorized in a variety of ways depending on their form, cell wall, flagella, nutrition, and morphology.
Gram-positive and gram-negative bacteria are distinguished by their staining patterns.