SPECIES
Species (abbreviated as sp., singular, or spp., plural) is the
most basic of the taxonomic groups and can be defined
as a collection of bacterial strains that share common
physiologic and genetic features and differ notably from
other microbial species. Occasionally, taxonomic subgroups
within a species, called subspecies, are recognized.
Furthermore, designations such as biotype, serotype, or
genotype may be given to groups below the subspecies
level that share specific but relatively minor characteristics.
For example, Klebsiella pneumoniae and Klebsiella
oxytoca are two distinct species within the genus Klebsiella.
Serratia odorifera biotype 2 and Treponema pallidum subsp.
pallidum are examples of a biotype and a subspecies designation.
A biotype is considered the same species with
the same characteristic genetic makeup that displays differential
physiologic characteristics. Subspecies are typically
environmentally isolated from the original species
but do not display significant enough divergence to be
classified as a biotype or a new species. Although these
subgroups may have some taxonomic importance, their
usefulness in diagnostic microbiology is limited.