Description of Erysipelothrix piscisicarius sp. nov., an emergent fish pathogen, and assessment of virulence using a tiger barb (Puntigrus tetrazona) infection model. Issue 2 (4th November 2019)

• Record Type: Journal Article
• Authors: Pomaranski, Eric K.; Griffin, Matt J.; Camus, Alvin C.; Armwood, Abigail R.; Shelley, Johnny; Waldbieser, Geoffrey C.; LaFrentz, Benjamin R.; García, Julio C.; Yanong, Roy; Soto, Esteban
• Is Part Of: International journal of systematic and evolutionary microbiology. Volume 70:Issue 2(2020)
• Page Start: 857
• Page End: 867
• Publication Date: 2019-11-04
• Subjects: aquaculture -- emergent -- ornamental; Microbiology -- Periodicals; Microbiology -- Classification -- Periodicals; 579
• DOI: 10.1099/ijsem.0.003838
• Languages: English
• ISSNs: 1466-5026

Abstract

Abstract : A recently described emergent disease of ornamental fish has been associated with an Erysipelothrix species positive for the surface protective antigen ( spa ) C gene. Whole genome sequencing was performed on five spaC Erysipelothrix isolates from diseased ornamental fish. In addition, these spaC Erysipelothrix isolates were compared to spaA-, spaB- and other spaC -positive Erysipelothrix species isolated from terrestrial and marine mammals, birds and fish using multi-locus sequence analysis (MLSA). The genomes of fish pathogenic spaC isolates were genetically distinct from Erysipelothrix rhusiopathiae, sharing 86.61–86.94 % average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values of 31.6–32.2 %, but 99.01–99.11 % ANI and 90.8–91.9 % dDDH values with the uncharacterized spaC -positive Erysipelothrix sp. strain 2 isolated from swine. The findings indicate the spaC -positive fish and swine isolates are conspecific and represent a previously unrecognized taxon. While phylogenies inferred from MLSA sequences confirm this conclusion, slight genetic differences between the spaC fish isolates and swine strain 2 were indicated. Bath immersion challenge trials were conducted using tiger barbs ( Puntigrus tetrazona ) exposed by immersion to 10 7 c.f.u. ml −1 of three fish pathogenic spaC Erysipelothrix species, and three spaA and two spaB E. rhusiopathiae isolates as a model of infection. Thirty days post-challenge, cumulative mean percentage survival was 37 % for the spaA, 100 % for the spaB and 13 % for the spaC isolates, revealing differences in virulence among the various spa genotypes in fish. Genetic findings and observed differences in virulence demonstrate the fish pathogenic spaC isolates represent a novel species, for which the name Erysipelothrix piscisicarius sp. nov. is proposed. The type strain is E. piscisicarius 15TAL0474 T (=NRRL B-65533 T =ATCC-TSD-175 T =DSM 110099 T ).