Comparative genome analysis of Campylobacter fetus subspecies revealed horizontally acquired genetic elements important for virulence and niche specificity

• Published in: PloS one 2014-01, Vol.9 (1), p.e85491-e85491
• Main Authors: Kienesberger, Sabine, Sprenger, Hanna, Wolfgruber, Stella, Halwachs, Bettina, Thallinger, Gerhard G, Perez-Perez, Guillermo I, Blaser, Martin J, Zechner, Ellen L, Gorkiewicz, Gregor
• Format: Article
• Language: English
• Subjects: Adaptation; Analysis; Animals; Bacteria; Bacterial genetics; Bacterial Secretion Systems - genetics; Base Sequence; Bioinformatics; Biological evolution; Biology; Biosynthesis; Bovidae; Campylobacter; Campylobacter fetus; Campylobacter fetus - classification; Campylobacter fetus - genetics; Campylobacter fetus - pathogenicity; Campylobacter Infections - microbiology; Cattle; Chromosome Mapping; Chromosomes, Bacterial - chemistry; Comparative analysis; CRISPR; Deactivation; DNA, Bacterial - genetics; Fetuses; Fitness; Functional analysis; Functional groups; Gene expression; Gene transfer; Gene Transfer, Horizontal; Genes; Genital tract; Genome, Bacterial; Genomes; Genomics; Harbors; Host range; Host Specificity; Humans; Inactivation; Infections; Intestine; Lipopolysaccharides; Lipopolysaccharides - biosynthesis; Lipopolysaccharides - genetics; Mitogens; Molecular Sequence Data; Nucleotide sequence; Pathogenesis; Pathogenicity; Pathogens; Pathology; Physiological aspects; Proteins; Reproductive fitness; Reptiles & amphibians; Secretion; Sequence Analysis, DNA; Species Specificity; Synteny; Virulence; Virulence (Microbiology)
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0085491

Campylobacter fetus are important animal and human pathogens and the two major subspecies differ strikingly in pathogenicity. C. fetus subsp. venerealis is highly niche-adapted, mainly infecting the genital tract of cattle. C. fetus subsp. fetus has a wider host-range, colonizing the genital- and intestinal-tract of animals and humans. We report the complete genomic sequence of C. fetus subsp. venerealis 84-112 and comparisons to the genome of C. fetus subsp. fetus 82-40. Functional analysis of genes predicted to be involved in C. fetus virulence was performed. The two subspecies are highly syntenic with 92% sequence identity but C. fetus subsp. venerealis has a larger genome and an extra-chromosomal element. Aside from apparent gene transfer agents and hypothetical proteins, the unique genes in both subspecies comprise two known functional groups: lipopolysaccharide production, and type IV secretion machineries. Analyses of lipopolysaccharide-biosynthesis genes in C. fetus isolates showed linkage to particular pathotypes, and mutational inactivation demonstrated their roles in regulating virulence and host range. The comparative analysis presented here broadens knowledge of the genomic basis of C. fetus pathogenesis and host specificity. It further highlights the importance of surface-exposed structures to C. fetus pathogenicity and demonstrates how evolutionary forces optimize the fitness and host-adaptation of these pathogens.