The taxonomic history of these bacteria has been
dominated by their biochemical inertness. Classical phenotypic
tests routinely used for the identification of clinically signifi-
cant bacteria often yield negative results or yield variable results within species. This lack of differential characteristics led
to the widespread use of vernacular names for many isolates,
e.g., gastric Campylobacter-like organisms or urease-producing
thermophilic campylobacters (terms reflecting the unusual isolation sources or aberrant phenotypic characteristics of the
strains). Over a period of about 30 years, these groups were
detected, described, and identified as different biotypes of existing species or as new species. The genus Campylobacter
became a deposit for a wide assemblage of taxa characterized
by a minimal set of phenotypic characteristics including the
microaerobic growth requirements and a nonsaccharolytic metabolism