Genomic and Physiological Growth Kinetics Analysis of a Novel Lytic Aeromonas Phage AhP_Mru1 Against Aeromonas hydrophila

Bacteriophages serve as natural biocontrol agents and are viable alternatives to antibiotics for the management of bacterial infections in aquaculture. Aeromonas hydrophila , a significant fish pathogen, has developed multidrug resistance. This study aimed to isolate and characterize a lytic bacteriophage targeting A. hydrophila . AhP_Mru1 , a novel lytic bacteriophage against A. hydrophila , was isolated from the Pawana River in Pune, Maharashtra, India. Using conventional enrichment and plaque purification procedures, spot tests, and transmission electron microscopy, we revealed its tailed morphology with an icosahedral capsid. Whole-genome sequencing revealed that AhP_Mru1 has a 117-kb double-stranded DNA genome with a high GC content and encodes genes for DNA replication, metabolism, and host lysis but lacks integrase or toxin genes. Comparative genomic analysis showed <95% similarity to closely related Aeromonas phages, and phylogenetic analyses placed it in the genus Shenzhenvirus of the family Demerecviridae . AhP_Mru1 genomic features and taxonomic position distinguish it as a novel phage species.