Campylobacter and Arcobacter

Abstract

Campylobacteraceae is composed of three main genera, Campylobacter, Sulfurospirillum, and Arcobacter, and is represented currently by 43 described or proposed species. Unlike Campylobacter spp., that are associated with warm-blooded avian and mammalian hosts, members of the Sulfurospirillum and Arcobacter genera are non-host-associated, free-living, environmental organisms. Arcobacter spp. can grow aerobically, unlike campylobacters, which are restricted to microaerobic and/or anaerobic environments. The organisms whose genomes have been or are being sequenced are (i) host-associated or free-living; (ii) nonpathogenic, human commensals, or human pathogens (oral or gastrointestinal); or (iii) food or environmental isolates. Analysis of these genomes alongside comparative genomics will provide clues pertaining to the genetic nature of pathogenicity, host association, environmental adaptation, and evolution. The chapter addresses the topics related to the Campylobacter and Arcobacter genomes. The coding sequences (CDSs) with assigned function are fairly consistent across the sequenced Campylobacteraceae genomes, with an assigned function/total CDSs average of 45%. It is possible that many Campylobacter species are composed of multiple host-associated phylogenetic clusters. Comparative genomics of the Campylobacter and Arcobacter genomes has not identified any pathogenicity islands containing toxin-encoding genes or other virulence determinants. Campylobacter and Arcobacter species provide fertile ground for comparative genomics. Therefore, comparative genomics of Campylobacter and Arcobacter should provide insights into pathogenicity, host adaptation and specificity, evolution, and environmental adaptation and survival. The degree of variation within Campylobacter and Arcobacter is an important consideration.