The Family Campylobacteraceae

The Campylobacteraceae is the largest and most diverse family in the phylogenetically distinct Epsilonproteobacteria, presently comprising the genera Campylobacter (30 taxa), Arcobacter (17 taxa), and Sulfurospirillum (7 taxa). Individual species may be able to grow in microaerobic, anaerobic, and/or aerobic conditions, in temperatures from 25°C to 42°C; free-living, commensal, or pathogenic; motile or aflagellate; and able to colonize the oral cavity, intestine, stomach, or reproductive tracts of humans, large production animals (such as sheep, cattle, and deer), birds, and reptiles. Some species are known to be among the most frequent causes of human gastroenteritis, others are significant threats to bovine and ovine fertility, and many pose an as-yet unknown, or no, role in human or animal diseases. The taxonomy of the Campylobacteraceae has evolved extensively since its beginnings in 1963. This chapter outlines key events in the family's taxonomic history; reviews general phenotypic traits of each genus, including their isolation; outlines the clinical (including pathogenicity studies and antimicrobial resistance traits) and/or ecological significance of constituent species; and describes current approaches and challenges for species identification and epidemiological subtyping

Identity of epibiotic bacteria on symbiontid euglenozoans in O2-depleted marine sediments: evidence for symbiont and host co-evolution

A distinct subgroup of euglenozoans, referred to as the ‘Symbiontida,' has been described from oxygen-depleted and sulfidic marine environments. By definition, all members of this group carry epibionts that are intimately associated with underlying mitochondrion-derived organelles beneath the surface of the hosts. We have used molecular phylogenetic and ultrastructural evidence to identify the rod-shaped epibionts of the two members of this group, Calkinsia aureus and B.bacati, hand-picked from the sediments of two separate oxygen-depleted, sulfidic environments. We identify their epibionts as closely related sulfur or sulfide-oxidizing members of the epsilon proteobacteria. The epsilon proteobacteria generally have a significant role in deep-sea habitats as primary colonizers, primary producers and/or in symbiotic associations. The epibionts likely fulfill a role in detoxifying the immediate surrounding environment for these two different hosts. The nearly identical rod-shaped epibionts on these two symbiontid hosts provides evidence for a co-evolutionary history between these two sets of partners. This hypothesis is supported by congruent tree topologies inferred from 18S and 16S rDNA from the hosts and bacterial epibionts, respectively. The eukaryotic hosts likely serve as a motile substrate that delivers the epibionts to the ideal locations with respect to the oxic/anoxic interface, whereby their growth rates can be maximized, perhaps also allowing the host to cultivate a food source. Because symbiontid isolates and additional small subunit rDNA gene sequences from this clade have now been recovered from many locations worldwide, the Symbiontida are likely more widespread and diverse than presently known