Tenacibaculum finnmarkense sp. nov., a fish pathogenic bacterium of the family Flavobacteriaceae isolated from Atlantic salmon

Abstract

A novel Gram-stain negative, aerobic, non-flagellated, rod-shaped gliding bacterial strain, designated HFJ(T), was isolated from a skin lesion of a diseased Atlantic salmon (Salmo salar L.) in Finnmark, Norway. Colonies were observed to be yellow pigmented with entire and/or undulating margins and did not adhere to the agar. The 16S rRNA gene sequence showed that the strain belongs to the genus Tenacibaculum (family Flavobacteriaceae, phylum 'Bacteroidetes'). Strain HFJ(T) exhibits high 16S rRNA gene sequence similarity values to Tenacibaculum dicentrarchi NCIMB 14598(T) (97.2 %). The strain was found to grow at 2-20 °C and only in the presence of sea salts. The respiratory quinone was identified as menaquinone 6 and the major fatty acids were identified as summed feature 3 (comprising C16:1 ω7c and/or iso-C15:0 2-OH), iso-C15:0, anteiso-C15:0, iso-C15:1 and iso-C15:0 3-OH. The DNA G+C content was determined to be 34.1 mol%. DNA-DNA hybridization and comparative phenotypic and genetic tests were performed with the phylogenetically closely related type strains, T. dicentrarchi NCIMB 14598(T) and Tenacibaculum ovolyticum NCIMB 13127(T). These data, as well as phylogenetic analyses, suggest that strain HFJ(T) should be classified as a representative of a novel species in the genus Tenacibaculum, for which the name Tenacibaculum finnmarkense sp. nov. is proposed; the type strain is HFJ (T) = (DSM 28541(T) = NCIMB 42386(T)).

Keywords: Norway; Polyphasic taxonomy; Salmon farming; Skin lesions; Ulcerative disease; Winter ulcers.

Fig. 1

The relationship of the novel species T. finnmarkense sp. nov HFJ^T and the 21 type strains in genus Tenacibaculum (^* = quotation marks denote names that have not been validly published) based on the 16S rRNA gene sequences, using Kordia algicida ^T as outgroup. The phylogenetic analysis was inferred using the Bayesian method with the best fitted evolutionary model (GTR + G + I). The posterior probability is presented next to each node in percentage. There were a total of 1341 positions in the dataset. Evolutionary analyses were conducted using BEAST package v1.8. Shared nodes identified in corresponding ML analysis are marked with filled squares. Accesion numbers are in parentheses. Scale bar 0.05 substiutions per site

Fig. 2

The relationship of the novel species T. finnmarkense sp.nov HFJ^T, Tenacibaculum sp. strains Tsp. 2–7 and the three closest related type strains based on 16S rRNA gene sequences, using T. maritimum NCIMB 2154^T as outgroup. The phylogenetic analysis was inferred using the Bayesian method with the best fitted evolutionary model (HKY + G + I). The posterior probability is presented next to each node in percentage. There were a total of 1349 positions in the dataset. Evolutionary analyses were conducted using BEAST package v1.8. Shared nodes identified in corresponding ML analysis are marked with filled squares. Accesion numbers are in parentheses. Scale bar 0.02 substitutions per site

Fig. 3

The relationship of the novel species T. finnmarkense sp.nov HFJ^T, Tenacibaculum sp. strains Tsp. 2–7 and the three closest related type strains based on a concatenated sequences of five HK genes (atpD at position 1–807, fusA at position 808–1575, pgk at position 1576–2511, rpoB at position 2512–5778 and tuf at position 5779–6750), using T. maritimum ^T as outgroup. The accession numbers for the HK genes used in the concatenated dataset are presented in Table 3. The phylogenetic analysis was inferred using the Bayesian method with the best fitted evolutionary model. The posterior probability is presented next to each node in percentage. There were a total of 6750 positions in the dataset. Evolutionary analyses were conducted using KAKUSAN4 and Mr.Bayes. Shared nodes identified in corresponding ML analysis are marked with filled squares. Scale bar 0.05 substitutions per site