<unk>  is a genus of Gram-negative, spiral-shaped bacteria in the epsilonproteobacteria class. It shows an unusually wide range of habitats, and some species can be human and animal pathogens.  Species of the genus<unk>  are found in both animal and environmental sources, making it unique among the epsilonproteobacteria.  This genus currently consists of five species:  A. butzleri, A. cryaerophilus, A. skirrowii, A. nitrofigilis, and A. sulfidicus, although several other potential novel species have recently been described from varying environments.    Three of these five known species are pathogenic.  Members of this genus were first isolated in 1977 from aborted bovine fetuses.  They are aerotolerant Campylobacter-like organisms, previously classified as Campylobacter.  The<unk>  genus, in fact, was created as recently as 1992.  Although they are similar to this other genus,<unk>  species can grow at lower temperatures than Campylobacter as well as in the air, which Campylobacter cannot.
The name<unk>  is derived from the Latin "arcus" meaning "bow" and the Greek "bacter" meaning "rod", and should be understood to mean "bow-shaped rod" or "curved rod".  This is a reference to the characteristic curved shaped that most<unk>  cells possess.
Arcobacter
Bacteroides
Streptococcus
Pseudomonas
Lactobacillus
Helicobacter
Listeria
Legionella