Polyphasic study of Chryseobacterium strains isolated from diseased aquatic animals

Abstract

Members of most Chryseobacterium species occur in aquatic environments or food products, while strains of some other species are pathogenic to humans and animals. A collection of 52 Chryseobacterium sp. strains isolated from diseased fish, one frog isolate and 22 reference strains were included in a polyphasic taxonomy study. Fourteen clusters of strains were delineated following the comparison of whole-cell protein profiles. Most of these clusters were confirmed when the phenotypic and RAPD profiles and the 16S rRNA gene sequences were compared. Fatty acid composition helped differentiate the Chryseobacterium strains from members of related genera. None of the fish isolates could be allocated to the two species previously reported from fish but two isolates belonged to C. joostei, while the frog isolate was identified as Elizabethkingia meningoseptica, a human pathogen previously included in the genus Chryseobacterium. Three clusters grouping from 3 to 13 isolates will probably constitute the core of new Chryseobacterium species but all other isolates occupied separate or uncertain positions in the genus. This study further demonstrated the overall high similarity displayed by most Chryseobacterium strains whatever the technique used and the resulting difficulty in delineating new species in the genus. Members of this bacterial group should be considered potential emergent pathogens in various fish and frog species, farming conditions and geographical areas.

Chryseobacterium ureilyticum sp. nov., Chryseobacterium gambrini sp. nov., Chryseobacterium pallidum sp. nov. and Chryseobacterium molle sp. nov., isolated from beer-bottling plants

“…An in-depth analysis of the fatty acid profiles revealed some discrepancies with the profiles published previously for this genus (Mudarris et al, 1994;Bernardet et al, 2005;Kim et al, 2005b;Quan et al, 2007). We identified a compound as 17 : 1 iso cis9 that was previously named by the MIDI system as 17 : 1 iso v9c.…”

Chryseobacterium carnipullorum sp. nov., isolated from raw chicken

“…The type species is C. gleum. Members of the genus Chryseobacterium include psychrotolerant and proteolytic spoilage micro-organisms that are widely distributed in food sources such as milk, fish, meat and poultry (Hugo et al, 2003;de Beer et al, 2005 de Beer et al, , 2006 and occur in a variety of ecological niches such as soil, water, sludge, plants, and human and fish clinical specimens (Hugo et al, 2003;Bernardet et al, 2005Bernardet et al, , 2011Hugo & Jooste, 2012).In 2006 the genus Chryseobacterium consisted of only 10 validly named species. Since then the genus has undergone significant and rapid expansion and, at the time of writing, it comprises 61 species with validly published names (Bernardet et al, 2006) and more continue to be described (Euzéby, 2012).…”

Chryseobacterium piscicola sp. nov., isolated from diseased salmonid fish

“…1). Interestingly, when the sequence of strain VQ-6316s T was compared with those of Chryseobacterium strains isolated from fish published by Bernardet et al (2005), it shared nearly 100 % sequence similarity with strains UOF CR4395 and UOF CR2995 (GenBank accession nos AY468455 and AY468454, respectively), isolated from Atlantic salmon in Finland.…”

“…Within this family, the genera Bergeyella, Chryseobacterium and Riemerella form a separate branch on the basis of rRNA cistron similarity studies and phenotypic characterization (Vandamme et al, 1994). At the time of writing, the genus Chryseobacterium comprised 38 species, some of which are pathogenic to humans and animals (Bernardet et al, 2002(Bernardet et al, , 2005(Bernardet et al, , 2006. During the characterization of bacteria isolated from external lesions of diseased farmed Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) in Osorno, Chile, eight yellow-pigmented strains were recovered on modified Anacker and Ordal's agar (AOA; 0.5 % tryptone, 0.05 % yeast extract, 0.02 % beef extract, 0.02 % sodium acetate, pH 7.2; Anacker & Ordal, 1955) incubated at 15 u C. Five strains were isolated from rainbow trout (VQ-106r, VQ-5916r, VQ-5946r, VQ-5926r, VQ5966r) and the remaining three isolates (VQ-2206s, VQ4836s, VQ-6316s T ) were recovered from Atlantic salmon.…”