title: A new variant of cytolethal distending toxin in a clinical isolate of Campylobacter hyointestinalis.
abstract: Increasing numbers of Campylobacter hyointestinalis have been isolated from humans and animals with gastroenteritis, although the virulence mechanism of this species remains largely unknown. Here, we show that C. hyointestinalis isolated from a patient with diarrhoea in Thailand produced a novel variant of cytolethal distending toxin (CDT). Sequencing of a 13 965 bp genomic region of C. hyointestinalis carrying the genes coding for Ch-CDT revealed three ORFs of 798, 804 and 537 bp, which code for the Ch-CdtA, Ch-CdtB and Ch-CdtC subunits, respectively. The deduced amino acid sequence of Ch-CdtA showed ∼38.9 % homology with the CdtA of Campylobacter coli, but sequences of Ch-CdtB and Ch-CdtC were homologous to CdtB (65.7 %) and CdtC (33.1 %) of Campylobacter upsaliensis, respectively. Filter-sterilized sonic lysate of C. hyointestinalis demonstrated distension and death of HeLa cells by arresting the cell cycle at the G(2)/M phase and phosphorylation of host histone H2AX, a sensitive marker of DNA double-strand breaks. Rabbit antiserum raised against recombinant Ch-CdtB was not reactive against the recombinant CdtB protein of Campylobacter jejuni. A reconstituted Ch-CDT holotoxin prepared using each of the recombinant subunit proteins demonstrated distension and death of HeLa cells, suggesting that the C. hyointestinalis isolate indeed produced functionally active Ch-CDT. Furthermore, the immunological distinctiveness of the Ch-CDT produced by C. hyointestinalis and the increasing prevalence of the species in patients and animals with gastroenteritis suggest that this species may be an important emerging zoonotic pathogen.
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.|Faculty of Allied Health Sciences, Thammasat University, Pathumthani, Thailand.
authors.forename: Worada
authors.initials: W
authors.lastname: Samosornsuk
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.|Graduate School of Pharmaceutical Sciences, Osaka University, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Kamei
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Hatanaka
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taguchi
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Asakura
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Srinuan
authors.initials: S
authors.lastname: Somroop
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Sugimoto
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.|Department of Parasitology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wanpen
authors.initials: W
authors.lastname: Chaicumpa
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamasaki
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics* / Q000633:toxicity*; D002169:Campylobacter Infections / Q000382:microbiology*; D044862:Campylobacter hyointestinalis / Q000235:genetics* / Q000302:isolation & purification*; D002470:Cell Survival / Q000187:drug effects; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology*; D004847:Epithelial Cells / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA; D013785:Thailand
chemical_list: D001427:Bacterial Toxins; D004269:DNA, Bacterial; C067044:cytolethal distending toxin