Taxonomy, epidemiology, and clinical relevance of the genus Arcobacter

Abstract

The genus Arcobacter, defined almost 20 years ago from members of the genus Campylobacter, has become increasingly important because its members are being considered emergent enteropathogens and/or potential zoonotic agents. Over recent years information that is relevant for microbiologists, especially those working in the medical and veterinary fields and in the food safety sector, has accumulated. Recently, the genus has been enlarged with several new species. The complete genomes of Arcobacter butzleri and Arcobacter nitrofigilis are available, with the former revealing diverse pathways characteristic of free-living microbes and virulence genes homologous to those of Campylobacter. The first multilocus sequence typing analysis showed a great diversity of sequence types, with no association with specific hosts or geographical regions. Advances in detection and identification techniques, mostly based on molecular methods, have been made. These microbes have been associated with water outbreaks and with indicators of fecal pollution, with food products and water as the suspected routes of transmission. This review updates this knowledge and provides the most recent data on the taxonomy, species diversity, methods of detection, and identification of these microbes as well as on their virulence potential and implication in human and animal diseases.

FIG. 1.

Neighbor-joining phylogenetic tree showing the relationship of the described Arcobacter species on the basis of the 16S rRNA gene. Bootstrap values (>50%) based on 1,000 replications are shown at the nodes of the tree. Bar, 1 substitution per 100 nucleotides. ATCC, American Type Culture Collection, Manassas, VA; CECT, Colección Española de Cultivos Tipo, Universidad de Valencia, Valencia, Spain; CCUG, Culture Collection of the University Göteborg, Göteborg, Sweden; LMG, Culture Collection of the Laboratorium voor Microbiologie Gent, Universiteit Gent, Gent, Belgium. Equivalence culture collection numbers A. halophilus LA31B^T, ATCC BAA-1022^T; A. marinus CL-S1^T, CECT 7727^T.

FIG. 2.

Virulence mechanisms described for Arcobacter in different cell lines and exemplified for intestinal epithelial cells. Strains of Arcobacters species have shown the capacity to produce cytotoxicity, adherence, invasion, and inflammation mediated by interleukin-8 (IL-8). The ability to decrease claudin expression in tight junctions (TJ) with dysfunction of the epithelial barrier and the concomitant increase in paracellular transport, which leads to leak flux type of diarrhea, have been demonstrated for A. butzleri in human colonic epithelial cells (HT-29/B6).