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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #370229

Research Project: Molecular Identification and Characterization of Bacterial and Viral Pathogens Associated with Foods

Location: Produce Safety and Microbiology Research

Title: Genetic characterization of Campylobacter concisus: strategies for improved genomospecies discrimination

item CORNELIUS, ANGELA - Institute Of Environmental Science And Research
item HUQ, MOHSINA - Royal Melbourne Institute Of Technology University
item ON, STEPHEN - Lincoln University - New Zealand
item FRENCH, NIGEL - Massey University
item VANDENBERG, OLIVIER - University Hospital Laboratory Of Brussels
item Miller, William - Bill
item LASTOVICA, ALBERT J - University Of The Western Cape
item ISTIVAN, TAGHRID - Royal Melbourne Institute Of Technology University
item BIGGS, PATRICK - Massey University

Submitted to: Systematic and Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2021
Publication Date: 3/4/2021
Citation: Cornelius, A.J., Huq, M., On, S.L., French, N.P., Vandenberg, O., Miller, W.G., Lastovica, A., Istivan, T., Biggs, P.J. 2021. Genetic characterization of Campylobacter concisus: strategies for improved genomospecies discrimination. Systematic and Applied Microbiology. 44. Article 126187.

Interpretive Summary: Campylobacter concisus is a member and type species of a related cluster of campylobacters termed the C. concisus group. Species in this group were isolated originally from the human oral environment, from patients with periodontal disease, gingivitis or from normal gum tissue. C. concisus group members were long considered to be innocuous human commensals that caused no disease. However, for C. concisus that original diagnosis has been modified considerably: C. concisus has been isolated from instances of human gastroenteritis (ranging from mild diarrhea to dysentery) and is increasingly associated with serious human illness, e.g. Crohn’s disease. C. concisus is a very diverse species and it is unknown whether the species as a whole has the potential to induce acute human illness or if this potential is restricted to certain subsets of strains within the species. To obtain a more accurate map of variation within C. concisus, the DNA sequences of 190 C. concisus strains were determined. This study showed clear separation of C. concisus into two groups. The relative pathogenic potential of each group remains to be determined.

Technical Abstract: Campylobacter concisus is a phenotypically and genetically heterogeneous species that has been isolated from a variety of sites in the human body, including stool samples from healthy and diarrhoeic individuals. With whole genome sequencing (WGS) becoming increasingly available, we aimed to evaluate the ability of a range of genome-based phylogenetic tools to distinguish between the two C. concisus genomospecies (GS). A collection of 190 C. concisus genomes and nine genomes representing related Campylobacter species were included in some analyses in the study to provide context. Analyses incorporating sequence analysis of multiple ribosomal genes, such as ribosomal multi-locus sequence typing (rMLST) and ribosomal RNA (rrn) operon analysis, generated similar levels of C. concisus GS discrimination as genome-wide comparisons such as average nucleotide identity (ANI) and genome BLAST distance phylogeny (GBDP). The C. concisus genomes formed two groups; one is represented by the type strain ATCC 33237T (GS1) and the other by CCUG 19995 (GS2). The two C. concisus GS were separated from the nine genomes representing related species. GS1 and GS2 also exhibited differences in GC content with medians of 37.56% and 39.51%, respectively. The groups are consistent with previously established GS and are supported by DNA reassociation results. Pan-genomic analysis identified genes specific to GS1 and GS2. Whole genome sequence (WGS) data and genomic species identification methods have provided additional support for the existence of GS within C. concisus. These data support genomic species identification methods as a viable option for tentatively assigning partially characterized isolates to a taxonomic group.