Dataset Information

Comparative Genomics of Campylobacter fetus from Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages.

ABSTRACT: 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.

SUBMITTER: Gilbert MJ

PROVIDER: S-EPMC4943207 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Comparative Genomics of Campylobacter fetus from Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages.

Gilbert Maarten J MJ Miller William G WG Yee Emma E Zomer Aldert L AL van der Graaf-van Bloois Linda L Fitzgerald Collette C Forbes Ken J KJ Méric Guillaume G Sheppard Samuel K SK Wagenaar Jaap A JA Duim Birgitta B

Genome biology and evolution 20160702 6

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 t ...[more]

PMID: 27333878

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Project description:Campylobacter fetus is a pathogen, which is primarily associated with fertility problems in sheep and cattle. In humans, it can cause severe infections that require antimicrobial treatment. However, knowledge on the development of antimicrobial resistance in C. fetus is limited. Moreover, the lack of epidemiological cut-off values (ECOFFs) and clinical breakpoints for C. fetus hinders consistent reporting about wild-type and non-wild-type susceptibility. The aim of this study was to determine the phenotypic susceptibility pattern of C. fetus and to determine the C. fetus resistome [the collection of all antimicrobial resistance genes (ARGs) and their precursors] to describe the genomic basis of antimicrobial resistance in C. fetus isolates over time. Whole-genome sequences of 295 C. fetus isolates, including isolates that were isolated in the period 1939 till the mid 1940s, before the usage of non-synthetic antimicrobials, were analysed for the presence of resistance markers, and phenotypic antimicrobial susceptibility was obtained for a selection of 47 isolates. C. fetus subspecies fetus (Cff) isolates showed multiple phenotypic antimicrobial resistances compared to C. fetus subspecies venerealis (Cfv) isolates that were only intrinsic resistant to nalidixic acid and trimethoprim. Cff isolates showed elevated minimal inhibitory concentrations for cefotaxime and cefquinome that were observed in isolates from 1943 onwards, and Cff isolates contained gyrA substitutions, which conferred resistance to ciprofloxacin. Resistances to aminoglycosides, tetracycline and phenicols were linked to acquired ARGs on mobile genetic elements. A plasmid-derived tet(O) gene in a bovine Cff isolate in 1999 was the first mobile genetic element observed, followed by detection of mobile elements containing tet(O)-aph(3')-III and tet(44)-ant(6)-Ib genes, and a plasmid from a single human isolate in 2003, carrying aph(3')-III-ant(6)-Ib and a chloramphenicol resistance gene (cat). The presence of ARGs in multiple mobile elements distributed among different Cff lineages highlights the risk for spread and further emergence of AMR in C. fetus. Surveillance for these resistances requires the establishment of ECOFFs for C. fetus.

Dataset Information

Comparative Genomics of Campylobacter fetus from Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages.

Publications

Comparative Genomics of Campylobacter fetus from Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages.

Similar Datasets

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