A focus on the meaning of bacterial species

The significance of the term “individual” as applied to the definition of the taxon “species” is reviewed. For clarity in classification and nomenclature in bacteriology it is urged that (1) for each genus there should be definite designation of a type species, (2) for each species there should be recognition either of a type strain or of a neotype strain. These should be accessible in true type culture collections for distribution and use. For each type or neotype strain there should be available a reasonably complete description which may be emended as new techniques of differentiation are developed and applied. The concept of type and neotype in many cases should be carried to the level of subspecies and not infrequently to infrasubspecific forms, including strains useful in diagnosis in chemical studies, serotypes, variants and strains useful in industry.