Pseudomonas arcuscaelestis sp. nov., isolated from rainbow trout and water

Abstract

Cells of strains P66T, V1 and W15Feb18 are Gram-stain-negative short rods and motile by one polar flagellum. Strain P66T was isolated from rainbow trout (Oncorhynchus mykiss) cultivated at a fish farm in Turkey. Strain V1 was isolated from sand of an intertidal shore on the Galicia coast in Spain and strain W15Feb18 was isolated from water collected at the Woluwe River in Belgium. Based on 16S rRNA sequence similarity values, the strains were grouped under the genus Pseudomonas and the Pseudomonas putida phylogenetic group of species. The DNA G+C content ranged from 58.5 to 58.9 mol%. The strains were characterized phenotypically by the API 20NE and Biolog GEN III tests, and chemotaxonomically by their whole-cell MALDI-TOF MS protein profiles and fatty acid contents. The absence of the hydrolysis of gelatin and the assimilation of arabinose, mannose and mannitol differentiated these strains from the closest species, Pseudomonas alkylphenolica . The major fatty acid components were C16:0 (29.91–31.68 %) and summed feature 3 (36.44–37.55 %). Multilocus sequence analysis with four and 83 housekeeping gene sequences and a core proteome analysis showed that these strains formed a phylogenetic cluster in the P. putida group of species. Genome comparisons by the average nucleotide identity based on blast and the Genome-to-Genome Distance Calculator demonstrated that the three strains belonged to the same genomic species and were distant from any known species, with similarity values lower than the thresholds established for species in the genus Pseudomonas . These data permitted us to conclude that strains P66T, V1 and W15Feb18 belong to a novel species in the genus Pseudomonas , for which the name Pseudomonas arcuscaelestis sp. nov. is proposed. The type strain is P66T (=CECT 30176T=CCUG 74872T). The other strains have been deposited in the CECT with the corresponding collection numbers: V1 (=CECT 30356) and W15Feb18 (=CECT 30355).

General Assessment of Approaches to the Identification of Aquatic Bacterial Pathogens: A Methodological Review

“…Thus, previous research has shown that while MALDI-TOF MS is capable of identifying some common fish pathogens, the current database falls short in identifying uncommon and novel species. The identification of novel fish pathogens in the past few years (Duman et al 2020(Duman et al , 2021b(Duman et al , 2021aMulet et al 2021;Saticioglu et al 2021aSaticioglu et al , 2021bSaticioglu et al , 2021c has clearly demonstrated that MALDI-TOF MS analysis alone would not suffice in microbial identification. Recent studies have demonstrated that while this method can be used for the identification of wellknown species and species for which the method's success has been confirmed, the complementary support of MALDI-TOF MS with phenotypic tests and basic molecular methods is required nonetheless.…”

“…2020, 2021b, 2021a; Mulet et al. 2021; Saticioglu et al. 2021a, 2021b, 2021c) has clearly demonstrated that MALDI‐TOF MS analysis alone would not suffice in microbial identification.…”