Ornithogenic Ecosystems in the High Arctic as a Source of Virulent Bacteriophages

Background. Studying the diversity of bacteriophages in pristine Arctic ecosystems is of significant interest for determining strategies for finding viruses that can be used as antibacterial agents against multidrug-resistant bacteria. The aim of the study was to describe the structure and characteristics of viromes associated with seabird colonies on the Barents Sea islands as a potential source for virulent bacteriophages that can be used for phage therapy of infectious diseases in humans and animals. Material and methods. The study included metagenomic analysis of soil samples collected in the seabird colonies on Severny Island (Novaya Zemlya archipelago) and Western Northbrook Island (Franz-Josef Land archipelago), as well as isolation and sequencing of Escherichia coli bacteriophage genomes from these samples. Metagenomic sequencing was performed on a DNBSEQ-G400 sequencing platform with a paired-end read length of 150 base pairs. Further analysis included assembling raw reads into contigs using MEGAHIT version 1.2.9, followed by classification using Kraken2 and the RefSeq database of viral sequences. Bacteriophage isolation was achieved through the accumulation method using Escherichia coli flora2c and OO17 cultures. The genomes of the two isolated bacteriophages were sequenced, and their phylogenetic relationships were analyzed using the Parsnp program. Results. The structure of metaviromes is dominated by sequences of Caudoviricetes-class tailed phages, accounting for up to 78.45% of the total number of classified viral sequences. The analysis of metavirome data revealed a significant diversity of Caudoviricetes bacteriophages, including Straboviridae and Shitoviridae families and genera such as Baikalvirus and Phitrevirus . Representatives of these genera can be used in phage therapy. Two virulent Escherichia coli bacteriophages were isolated from ornithogenic soil samples. Based on phylogenomic analysis, one of them represents a known species of the genus Justusliebigvirus , while the second can be classified as a novel species of the genus Kagunavirus . Conclusion. The current study reveals a considerable diversity of virulent bacteriophage species in the microbiomes associated with Arctic seabird colonies, suggesting that there is potential for finding new bacteriophages applicable for phage therapy.