Whole genome sequence analysis indicates recent diversification of mammal-associated Campylobacter fetus and implicates a genetic factor associated with H2S production.
Campylobacter fetus (C. fetus) can cause disease in both humans and animals. C. fetus has been divided into three subspecies: C. fetus subsp. fetus (Cff), C. fetus subsp. venerealis (Cfv) and C. fetus subsp. testudinum (Cft). Subspecies identification of mammal-associated C. fetus strains is crucial in the control of Bovine Genital Campylobacteriosis (BGC), a syndrome associated with Cfv. The prescribed methods for subspecies identification of the Cff and Cfv isolates are: tolerance to 1 % glycine and H2S production.



In this study, we observed the deletion of a putative cysteine transporter in the Cfv strains, which are not able to produce H2S from L-cysteine. Phylogenetic reconstruction of the core genome single nucleotide polymorphisms (SNPs) within Cff and Cfv strains divided these strains into five different clades and showed that the Cfv clade and a Cff clade evolved from a single Cff ancestor.



Multiple C. fetus clades were observed, which were not consistent with the biochemical differentiation of the strains. This suggests the need for a closer evaluation of the current C. fetus subspecies differentiation, considering that the phenotypic differentiation is still applied in BGC control programs.
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.|WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands.
Linda
L
van der Graaf-van Bloois
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.|WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands.
Birgitta
B
Duim
U.S. Department of Agriculture, Produce Safety and Microbiology Research Unit, Agricultural Research Service, Albany, CA, USA.
William G
WG
Miller
School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK.
Ken J
KJ
Forbes
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.|WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands.|Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands.
Jaap A
JA
Wagenaar
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. A.L.Zomer@uu.nl.|WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for Campylobacteriosis, Utrecht, The Netherlands. A.L.Zomer@uu.nl.
Aldert
A
Zomer
D001426:Bacterial Proteins / Q000235:genetics; D002168:Campylobacter fetus / Q000145:classification* / Q000235:genetics / Q000502:physiology; D003545:Cysteine / Q000378:metabolism; D019143:Evolution, Molecular; D017353:Gene Deletion; D059646:Genome Size; D016680:Genome, Bacterial; D006862:Hydrogen Sulfide / Q000378:metabolism*; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA / Q000379:methods*
D001426:Bacterial Proteins; D003545:Cysteine; D006862:Hydrogen Sulfide
Bovine Genital Campylobacteriosis; Campylobacter fetus; Core genome SNP analysis; Cysteine transporter; H2S production; Subspecies differentiation