Elevation of Francisella philomiragia subsp. noatunensis Mikalsen et al. (2007) to Francisella noatunensis comb. nov. [syn. Francisella piscicida Ottem et al. (2008) syn. nov.] and characterization of Francisella noatunensis subsp. orientalis subsp. nov., two important fish pathogens.
OBJECTIVE
This study was conducted to clarify the taxonomic status of Francisella sp. strain Ehime-1, a fish pathogen, in relation to the fish pathogens F. piscicida and F. philomiragia subsp. noatunensis and to F. philomiragia subsp. philomiragia.


RESULTS
Francisella sp. Ehime-1 was compared to F. piscicida, F. philomiragia subsp. noatunensis and several F. philomiragia subsp. philomiragia isolates through sequencing of the 16S rRNA-gene and several house-keeping genes and determination of biochemical and phenotypic properties. Results show that F. piscicida is indistinguishable from F. philomiragia subsp. noatunensis by sequence and phenotypic traits. Francisella sp. Ehime-1 and F. philomiragia subsp. noatunensis are clearly separated from F. philomiragia. Francisella sp. Ehime-1 is biochemically, phenotypically and genetically different from F. philomiragia subsp. noatunensis (=F. piscicida), but DNA-DNA hybridization does not clearly support establishment as a separate species (level of relatedness 64% and 73.4%, mean 68.7%).


CONCLUSIONS
We propose to elevate F. philomiragia subsp. noatunensis to species rank as F. noatunensis comb. nov., while F. piscicida is considered a heterotypic synonym of F. noatunensis comb. nov. Evidence suggests that Francisella sp. Ehime-1 represents a novel subspecies of F. noatunensis, for which the name F. noatunensis subsp. orientalis subsp. nov. is proposed (=DSM21254(T), = LMG24544(T)).


CONCLUSIONS
This study contributes to the taxonomy and characteristics of fish-pathogenic Francisella spp.
Ottem
K F
KF
Department of Biology, University of Bergen, Norway. Karl.ottem@bio.uib.no
Nylund
A
A
Karlsbakk
E
E
Friis-Møller
A
A
Kamaishi
T
T
D000818:Animals; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005393:Fish Diseases / Q000382:microbiology; D005603:Francisella / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S