Bacteriophages are increasingly being used as biological control agents against pathogenic bacteria. In the present study, we isolate and characterize bacteriophage Akh-2 from Geoje Island, South Korea, to evaluate its utility in controlling motile Aeromonas septicemia. Akh-2 lysed four of the seven Aeromonas hydrophila strains tested. Transmission electron microscopy analysis showed that Akh-2 belongs to the Siphoviridae family, with head and tail sizes of 50 ± 5 and 170 ± 5 nm, respectively. One-step growth curve analysis revealed that the phage has a latent period of 50 ± 5 min and a burst size of 139 ± 5 plaque-forming units per infected cell. The phage appeared stable in a pH range of 6–8 and a temperature range of −80 to 46 °C. Based on next-generation sequencing analysis, its genome is 114,901 bp in size, with a 44.22% G + C content and 254 open reading frames. During an artificial induction of the disease, loach (Misgurnus anguillicaudatus) treated with Akh-2 showed an increased survival rate and time compared with the non-treated control. Our results suggest that Akh-2 is a potential biological agent for the treatment of Aeromonas infections in fish.

The fourth complete genome sequence of the white spot syndrome virus (WSSV) from Pacific white shrimp (Litopenaeus vannamei) isolated from Korea (WSSV-KR) was determined. The genome is composed of 295,884 bp encompassing 515 open reading frames (ORFs) among which 90 showed no sequence homology with any known protein in BLAST searches. The remaining 425 ORFs encode functional proteins including enzymes for nucleic acid metabolism, DNA replication and transcription, and several major structural proteins. Dot plot and linear comparisons of WSSV Korean strain with other WSSV isolates showed overall similarity but with some areas of sequence difference and one large deletion area.