The purpose of classification of microorganisms is to define the
pathogenic potential. For example, a Staphylococcus aureus
isolated from blood is more likely to be acting as a pathogen than
Staphylococcus epidermidisfrom the same site. Some bacteria
have the capacity to spread widely in the community and cause
serious disease, for example Corynebacterium diphtheriae and
Vibrio cholerae. Bacteria are identified using a series of physical
immunological or molecular characteristics.