Characterization and genomic analyses of Aeromonas hydrophila phages AhSzq-1 and AhSzw-1, isolates representing new species within the T5virus genus.

In this study, two bacteriophage isolates, AhSzq-1 and AhSzw-1 that specifically infect Aeromonas hydrophila strain KT998822, were isolated from seawater and characterized. One-step growth curves showed that the latent period of AhSzq-1 and AhSzw-1 are 50 min and 60 min, respectively. The sequence similarities between AhSzq-1 and AhSzw-1 were 88% at the DNA and 83% at the protein level, suggesting that these two phages are representatives of two different species. The virion morphology, DNA genome size and terminal repeats of these two phages are similar to those of viruses classified as T5virus phages. Both phylogenetic analyses and proteomic comparison show that AhSzq-1 and AhSzw-1 group with members of the T5virus genus. We thus propose these two phages as representative isolates of two new species within the T5virus genus.