Characterization of Swedish Campylobacter coli clade 2 and clade 3 water isolates

• Campylobacter jejuni and Campylobacter coli are important bacterial enteropathogens. Poultry is the best-known reservoir for Campylobacter infection but natural bodies of water have also been shown to be important pathways for transmission. Campylobacter can survive in cold water but most of the studies have focused on C. jejuni only. In this paper, we take a closer look at the biology and water survival strategies of C. coil. Eight C. coil isolates cultivated from raw (incoming) surface water at water plants in Sweden were characterized using whole-genome sequencing and phenotypical assays. Phylogenetic analysis assigned the Swedish water isolates to clades 2 and 3, known to include C. coil of environmental origin. In addition, 53 earlier published sequences of C. coil clade 2 and 3 from environmental waters were included for in silico analyses. Generally, clade 2 isolates had larger genomes, which included a functional tricarballylate utilization locus, while clade 3 isolates contained different genes involved in oxidative stress as well as putative virulence factors. The Swedish water isolates of clade 2 formed large, blurry bacterial colonies on agar, whereas clade 3 colonies were smaller. All Swedish isolates were motile, but clade 3 isolates formed larger motility zones on soft agar, and none of these isolates produced biofilm. Although water survival varied between the analyzed isolates, there were hardly any clade-specific significant differences. Our results highlight the diversity of C. coil in general, and show differences in metabolic capabilities and ways to handle oxidative stress between clade 2 and 3 water isolates.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Keyword

Campylobacter coli

phenotypic identification

waterborne pathogens

whole-genome sequencing

Publication and Content Type

ref (subject category)

art (subject category)