Biological and Genetic Characteristics of a New Bacteriophage Isolated from Cholera Vibrios from a Patient (Moscow, 2023)

Currently, cholera remains a relevant infectious disease that requires new alternative antimicrobial agents for treatment and prevention, which can be bacteriophages. The aim of the study was to obtain a new bacteriophage from a culture of cholera vibrios isolated from a patient in Moscow in 2023, and characterize its biological and genetic properties. Materials and methods . The toxigenic strain Vibrio cholerae O1 Ogawa 21197 was used in the work. A two-layer agar Grazia method was applied to study biological properties of the bacteriophage (morphology of negative colonies, sensitivity to high and low temperatures and chloroform, lytic activity and specificity). The morphology of phage particles was studied under an electron microscope. The genetic characterization was carried out on the basis of genomewide sequencing using the programs “SeqAnalyzer”, “PhageAnalyzer 2.0”, as well as the algorithms BLASTN 2.2.29 and BLASTX 2.12.0+. Results and discussion . Isolated bacteriophage forms transparent negative colonies with an uneven edge without secondary growth and halo on nutrient media. Electron microscopy revealed that the isolated bacteriophage has a multifaceted head and a short tail. The phage is specific and has high lytic activity against cholera vibrios isolated from humans, is sensitive to heat and resistant to chloroform and freezing. Analysis of the sequencing results has shown that the phage belongs to the Caudoviricetes class of the Zobellviridae family, the genome size is 48,074 bp with a G+C content=42.7 %. The resulting genome was checked for nucleotide sequence homology with DNA sequences of other bacteriophages. 9 Vibrio phage genomes of the Zobellviridae family of the Caudoviricetes class were found, having a high percentage of overlap, isolated out of the water in India.