Complete Genome Sequence of Type Strain Campylobacter fetus subsp. venerealis NCTC 10354T

Yee³

et al. 2016

Genome Biol Evol

Campylobacter fetus currently comprises three recognized subspecies, which display distinct host association. Campylobacter fetus subsp. fetus and C. fetus subsp. venerealis are both associated with endothermic mammals, primarily ruminants, whereas C. fetus subsp. testudinum is primarily associated with ectothermic reptiles. Both C. fetus subsp. testudinum and C. fetus subsp. fetus have been associated with severe infections, often with a systemic component, in immunocompromised humans. To study the genetic factors associated with the distinct host dichotomy in C. fetus, whole-genome sequencing and comparison of mammal- and reptile-associated C. fetus was performed. The genomes of C. fetus subsp. testudinum isolated from either reptiles or humans were compared with elucidate the genetic factors associated with pathogenicity in humans. Genomic comparisons showed conservation of gene content and organization among C. fetus subspecies, but a clear distinction between mammal- and reptile-associated C. fetus was observed. Several genomic regions appeared to be subspecies specific, including a putative tricarballylate catabolism pathway, exclusively present in C. fetus subsp. testudinum strains. Within C. fetus subsp. testudinum, sapA, sapB, and sapAB type strains were observed. The recombinant locus iamABC (mlaFED) was exclusively associated with invasive C. fetus subsp. testudinum strains isolated from humans. A phylogenetic reconstruction was consistent with divergent evolution in host-associated strains and the existence of a barrier to lateral gene transfer between mammal- and reptile-associated C. fetus. Overall, this study shows that reptile-associated C. fetus subsp. testudinum is genetically divergent from mammal-associated C. fetus subspecies.

Section: Methodsmentioning

confidence: 99%

Comparative Genomics ofCampylobacter fetusfrom Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages

Gilbert

Yee³

et al. 2016

Genome Biol Evol

“…To clarify the taxonomic structure of the C. fetus group and further characterize these putative novel taxa, the genomes of five strains, including the C. lanienae type strain NCTC 13004 and representatives of all three putative novel taxa, were sequenced to completion; additional genomes were sequenced to draft level. The genomes of all other described taxa within the C. fetus group have been sequenced to completion ( Gilbert et al 2013 , 2014 ; Miller et al 2016a , 2016b ; Oliveira et al 2016 ; Stynen et al 2011 ; van der Graaf-van Bloois et al 2014a , 2014b ); thus, a full comparative genomic analysis of the C. fetus group could be accomplished with the new genomic data.…”

Section: Introductionmentioning

confidence: 99%

Comparative Genomic Analysis Identifies a Campylobacter Clade Deficient in Selenium Metabolism

Genome Biology and Evolution

Yee

Lopes

et al. 2017

The nonthermotolerant Campylobacter species C. fetus, C. hyointestinalis, C. iguaniorum, and C. lanienae form a distinct phylogenetic cluster within the genus. These species are primarily isolated from foraging (swine) or grazing (e.g., cattle, sheep) animals and cause sporadic and infrequent human illness. Previous typing studies identified three putative novel C. lanienae-related taxa, based on either MLST or atpA sequence data. To further characterize these putative novel taxa and the C. fetus group as a whole, 76 genomes were sequenced, either to completion or to draft level. These genomes represent 26 C. lanienae strains and 50 strains of the three novel taxa. C. fetus, C. hyointestinalis and C. iguaniorum genomes were previously sequenced to completion; therefore, a comparative genomic analysis across the entire C. fetus group was conducted (including average nucleotide identity analysis) that supports the initial identification of these three novel Campylobacter species. Furthermore, C. lanienae and the three putative novel species form a discrete clade within the C. fetus group, which we have termed the C. lanienae clade. This clade is distinguished from other members of the C. fetus group by a reduced genome size and distinct CRISPR/Cas systems. Moreover, there are two signature characteristics of the C. lanienae clade. C. lanienae clade genomes carry four to ten unlinked and similar, but nonidentical, flagellin genes. Additionally, all 76 C. lanienae clade genomes sequenced demonstrate a complete absence of genes related to selenium metabolism, including genes encoding the selenocysteine insertion machinery, selenoproteins, and the selenocysteinyl tRNA.

“…Additionally, while the type genome of Campylobacter fetus subsp. venerealis has been sequenced (10), a complete genome (one gapless contig) is recommended due to the presence of both mobile elements and a suite of S-layer genes with repeated motifs in Campylobacter fetus subsp. venerealis strains (11, 12).…”

Section: Announcementmentioning

confidence: 99%

Complete Genome Sequences of the Campylobacter fetus subsp. venerealis , Campylobacter lari subsp. concheus , Campylobacter sputorum bv. sputorum, and Campylobacter volucris Type Strains

Microbiol Resour Announc

Yee

2019