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BMC Microbiol. 2015 Oct 12;15:208. doi: 10.1186/s12866-015-0537-y.

Brachyspira suanatina sp. nov., an enteropathogenic intestinal spirochaete isolated from pigs and mallards: genomic and phenotypic characteristics.

Author information

1
Department of Animal Breeding and Genetics, Global Bioinformatics Centre, Swedish University of Agricultural Sciences (SLU), SE750 07, Uppsala, Sweden. memoonamushtaq@yahoo.com.
2
Department of Animal Breeding and Genetics, Global Bioinformatics Centre, Swedish University of Agricultural Sciences (SLU), SE750 07, Uppsala, Sweden. saimazubair.mail@gmail.com.
3
Department of Bacteriology, National Veterinary Institute (SVA), SE751 89, Uppsala, Sweden. therese.rasback@sva.se.
4
Department of Animal Breeding and Genetics, Global Bioinformatics Centre, Swedish University of Agricultural Sciences (SLU), SE750 07, Uppsala, Sweden. erik.bongcam@slu.se.
5
Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE751 89, Uppsala, Sweden. desiree.jansson@sva.se.
6
Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE750 07, Uppsala, Sweden. desiree.jansson@sva.se.

Abstract

BACKGROUND:

The genus Brachyspira currently encompasses seven valid species that colonize the intestines of mammals and birds. In a previous study a group of strongly haemolytic isolates from pigs and mallards was provisionally described as a new species within genus Brachyspira, "B. suanatina", and enteropathogenic properties were demonstrated in a porcine challenge model.

METHODS:

In the current study characterization of B. suanatina was performed on the basis of cell morphology, growth characteristics, enzyme profiles, DNA-DNA hybridization (DDH) and whole genome comparisons. The draft genome sequence of B. suanatina strain AN4859/03 was determined and compared with the available genomes of all valid species of Brachyspira.

RESULTS:

According to morphological traits, growth characteristics and enzymatic profiles, B. suanatina was similar to the type strain of B. hyodysenteriae, but using the recommended threshold value of 70% similarity by DDH it did not belong to any of the recognized Brachyspira species (range 16-64% similarity). This was further supported by average nucleotide identity values. Phylogenetic analysis performed using housekeeping genes and core genomes of all valid Brachyspira sp. and "B. hampsonii" revealed that B. suanatina and B. intermedia formed a clade distinct from B. hyodysenteriae. By comparing the genomes of the three closely related species B. intermedia, B. hyodysenteriae and B. suanatina similar profiles of general genomic features and distribution of genes in different functional categories were obtained. However, the genome size of B. hyodysenteriae was smallest among the species, suggesting the possibility of reductive evolution in the divergence of this species. A bacteriophage region and a putative plasmid sequence were also found in the genome of B. suanatina strain AN4859/03.

CONCLUSIONS:

The results of our study suggest that despite being similar to B. hyodysenteriae phenotypically, B. suanatina should be regarded as a separate species based on its genetic characteristics. Based on characteristics presented in this report we propose that strains AN4859/03, AN1681:1/04, AN2384/04 and Dk12570-2 from pigs in Sweden and Denmark, and strains AN3949:2/02 and AN1418:2/01 isolated from mallards in Sweden, represent a unique species within genus Brachyspira. For this new species we propose the name B. suanatina for which the type strain is AN4859/03T (=ATCC® BAA-2592™=DSM 100974T).

PMID:
26458507
PMCID:
PMC4603578
DOI:
10.1186/s12866-015-0537-y
[Indexed for MEDLINE]
Free PMC Article

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