Arcobacter spp.

Clinical picture

Some Arcobacter species can cause diarrhoea in humans and animals. This infection involves usual stomach pains and nausea as well as aqueous diarrhoea but can also have an asymptomatic course. In general, a rather mild course of disease is observed in humans.

Main sources of infection

Arcobacter has an extremely diverse natural habitat. There are plant and animal associated species as well as some free-living environmental germs. Consequently, Arcobacter spp. can be found, amongst others, in waters, such as surface and river waters, waste water and sea water. Furthermore, species have been isolated from several foods, mainly of animal origin, such as beef, pork, sheep and poultry meat.

Characteristics

The genus Arcobacter constitutes together with the general Campylobacter and Sulfurospirillum in the family of Campylobacteraceae within the order of Campylobacterales of the epsilon proteobacteria.

The gram-negative Arcobacter were originally classified as Campylobacter and include several (partially pathogenic) species such as A. butzleri, A. cryaerophilus, A. skirrowii, A. nitrofigilis, A. halophilus, A. sulfidicus and A. cibarius. They are, however, significantly different from Campylobacters in terms of their growth even at low temperatures and because of their aerotolerance. They are between 0.5 and 3.0 μm long, 0.2 – 0.9 μm wide and grow in a temperature range of 15°C to 42°C with a growth optimum at approximately 30°C. Because of their monotrichous flagellation, they are mobile rods that are partly spirally shaped. Under unfavourable conditions, the bacteria are transformed into cocci that are similar to those of Campylobacter and probably represent a survival form.