Reclassification of francisella noatunensis subsp. Orientalis ottem et al. 2009 as francisella orientalis sp. nov., francisella noatunensis subsp. chilensis subsp. nov. and emended description of francisella noatunensis

Jose Gustavo Ramirez-Paredes, Pär Larsson, Kim D. Thompson, David J. Penman, Hans Jürgen Busse, Caroline Öhrman, Andreas Sjödin, Esteban Soto, Randolph H. Richards, Alexandra Adams, Duncan J. Colquhoun

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Francisella noatunensis is a fastidious facultative intracellular bacterial pathogen that causes ‘piscine francisellosis’, a serious disease affecting both marine and fresh water farmed and wild fish worldwide. Currently two F. noatunensis subspecies are recognized, i.e. F. noatunensis subsp. noatunensis and F. noatunensis subsp. orientalis. In the present study, the taxonomy of F. noatunensis was revisited using a polyphasic approach, including whole genome derived parameters such as digital DNA–DNA hybridization, whole genome average nucleotide identity (wg-ANIm), whole genome phylogenetic analysis, whole genome G+C content, metabolic fingerprinting and chemotaxonomic analyses. The results indicated that isolates belonging to F. noatunensis subsp. orientalis represent a phenotypically and genetically homogenous taxon, clearly distinguishable from F. noatunensis subsp. noatunensis that fulfils requirements for separate species status. We propose, therefore, elevation of F. noatunensis subsp. orientalis to the species rank as Francisella orientalis sp. nov. with the type strain remaining as Ehime-1T (DSM 21254T=LMG 24544T). Furthermore, we identified sufficient phenotypic and genetic differences between F. noatunensis subsp. noatunensis recovered from diseased farmed Atlantic salmon in Chile and those isolated from wild and farmed Atlantic cod in Northern Europe to warrant proposal of the Chilean as a novel F. noatunensis subspecies, i.e. Francisella noatunensis subsp. chilensis subsp. nov. with strain PQ1106T (CECT 9798T=NCTC14375T) as the type strain. Finally, we emend the description of F. noatunensis by including further metabolic information and the description of atypical strains.

Original languageEnglish (US)
Article number004009
Pages (from-to)2034-2048
Number of pages15
JournalInternational Journal of Systematic and Evolutionary Microbiology
Volume70
Issue number3
DOIs
StatePublished - Jan 1 2020

Keywords

  • Chilensis
  • Francisella new species
  • Francisella noatunensis subsp
  • Francisella orientalis
  • Francisella salmon Chile
  • Francisella tilapia
  • Tilapia diseases

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics

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