Isolation of Chryseobacterium siluri sp. nov., from liver of diseased catfish (Silurus asotus)

Woo Taek Oh; Jin Woo Jun; Sib Sankar Giri; Saekil Yun; Hyoun Joong Kim; Sang Guen Kim; Sang Wha Kim; Se Jin Han; Jun Kwon; Se Chang Park

doi:10.1016/j.heliyon.2020.e03454

Isolation of Chryseobacterium siluri sp. nov., from liver of diseased catfish (Silurus asotus)

Heliyon. 2020 Feb 22;6(2):e03454. doi: 10.1016/j.heliyon.2020.e03454. eCollection 2020 Feb.

Authors

Affiliations

¹ Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea.
² Department of Aquaculture, Korea National College of Agriculture and Fisheries, Jeonju 54874, Republic of Korea.

Abstract

Yellow-pigmented, circular bacteria (strain SNU WT7) were isolated from the liver of moribund eastern catfish (Silurus asotus). Our study focused on the taxonomic description of SNU WT7 using phylogenetic, phenotypic, and chemotaxonomic analyses. The 16S rRNA gene sequence of the SNU WT7 strain was highly similar to that of Chryseobacterium haifense H38^T (97.29% similarity), followed by Chryseobacterium hominis P2K6^T (97.22% similarity), while other species exhibited similarity values of less than 97.0%. The genome of strain SNU WT7 displayed average nucleotide identity and genome-to-genome distance values of 72.35% and 22.0%, respectively, which clearly indicated that the novel species was distant from the other Chryseobacterium species, with its closest relative being C. haifense H38^T. Furthermore, the phenotypic characteristics, including acid production from glucose, D-fructose, lactose, and maltose, of strain SNU WT 7 differed from those of C. haifense H38^T. The major polar lipid of the strain was phosphatidylethanolamine, and several unidentified aminolipids and lipids were also present. Similar to other Chryseobacterium species, the quinone system was composed mainly of MK-6. The genome of SNU WT7 is 2,690,367 bp with a G + C content of 43.6%. Taken together, our data indicate that the isolate SNU WT7 represents a novel species of the genus Chryseobacterium. Thus, we present the name Chryseobacterium siluri sp. nov. for the novel type strain SNU WT7^T (KCTC 72626, JCM 33707).

Keywords: Bacteria; Catfish; Chryseobacterium; Epidemiology; Microbial biotechnology; Microbial genomics; Microbiology; Microorganism; Phylogeny; South Korea.