Flavobacterium flabelliforme sp. nov. and Flavobacterium geliluteum sp. nov., Two Multidrug-Resistant Psychrotrophic Species Isolated From Antarctica

Abstract

Despite unfavorable Antarctic conditions, such as cold temperatures, freeze-thaw cycles, high ultraviolet radiation, dryness and lack of nutrients, microorganisms were able to adapt and surprisingly thrive in this environment. In this study, eight cold-adapted Flavobacterium strains isolated from a remote Antarctic island, James Ross Island, were studied using a polyphasic taxonomic approach to determine their taxonomic position. Phylogenetic analyses based on the 16S rRNA gene and 92 core genes clearly showed that these strains formed two distinct phylogenetic clusters comprising three and five strains, with average nucleotide identities significantly below 90% between both proposed species as well as between their closest phylogenetic relatives. Phenotyping revealed a unique pattern of biochemical and physiological characteristics enabling differentiation from the closest phylogenetically related Flavobacterium spp. Chemotaxonomic analyses showed that type strains P4023T and P7388T were characterized by the major polyamine sym-homospermidine and a quinone system containing predominantly menaquinone MK-6. In the polar lipid profile phosphatidylethanolamine, an ornithine lipid and two unidentified lipids lacking a functional group were detected as major lipids. These characteristics along with fatty acid profiles confirmed that these species belong to the genus Flavobacterium. Thorough genomic analysis revealed the presence of numerous cold-inducible or cold-adaptation associated genes, such as cold-shock proteins, proteorhodopsin, carotenoid biosynthetic genes or oxidative-stress response genes. Genomes of type strains surprisingly harbored multiple prophages, with many of them predicted to be active. Genome-mining identified biosynthetic gene clusters in type strain genomes with a majority not matching any known clusters which supports further exploratory research possibilities involving these psychrotrophic bacteria. Antibiotic susceptibility testing revealed a pattern of multidrug-resistant phenotypes that were correlated with in silico antibiotic resistance prediction. Interestingly, while typical resistance finder tools failed to detect genes responsible for antibiotic resistance, genomic prediction confirmed a multidrug-resistant profile and suggested even broader resistance than tested. Results of this study confirmed and thoroughly characterized two novel psychrotrophic Flavobacterium species, for which the names Flavobacterium flabelliforme sp. nov. and Flavobacterium geliluteum sp. nov. are proposed.

Overproduction of Xanthophyll Pigment in Flavobacterium sp. JSWR-1 under Optimized Culture Conditions

“…In the study JSWR-1 strain produced the highest amount of zeaxanthin at 10°C and 8.5 pH and no growth was observed above 35 degrees Celsius. Flavobacterium is common among cold-adapted species, especially psychrophilic ones [ 32 ]. Whereas carotenoids in bacterial cells protect them from UV radiation and oxidative stress and are involved in the mechanisms of membrane fluidity (damage) mechanisms, lycopene inhibits membrane fluidity [ 54 , 55 ].…”

“…The examined taxonomic group encompasses an average of 130 district species [ 29 ]. The group encompasses many taxonomic groups found in marine and Antarctic environments, characterized by their ability to survive in cold temperatures (psychrophilic) or tolerate such conditions (psychrotolerant) and their need for sodium ions for growth and development [ 30 - 33 ]. Flavobacterium sp.…”

Flavobacterium pygoscelis sp. nov., isolated from a chinstrap penguin chick (Pygoscelis antarcticus)

“…Sequence similarities to all other Flavobacterium species were ≤98.30 %. The sequence showed 100 % similarity to that of ‘ Flavobacterium flabelliforme ’ P4023, which was isolated previously from material at an abandoned bird nest on Lachman Cape of James Ross Island in Antarctica [35]. This species name has not yet been validated and therefore was not considered for further analysis in this study.…”

Effect of soil depth on the structure of bacterial composition in the active layer at five geologically distinct sites on James Ross and Vega Islands in Antarctica

“…The extensive deglaciated areas of the Ulu Peninsula, James Ross Island and nearby Vega Island offer the suitable conditions for active layer research. In this unique locality, microbiological research has focused mainly on the description of many novel species comprising phyla Pseudomonadota and Bacteroidota from abiotic sources in last years (Kosina et al 2016;Sedláček et al 2017Sedláček et al , 2019aSedláček et al , b, 2020Sedláček et al , 2021Švec et al 2017, 2022Pantůček et al 2018;Králová et al 2019Králová et al , 2021Holochová et al 2020). Only one bacterial composition study was performed between two different soil profiles (60 cm soil profile from Brandy Bay location and 90 cm from Santa Martha Cove) (Meier et al 2019).…”