Genomic analysis of a novel active prophage of Hafnia paralvei.

Little is known about the prophages in Hafniaceae bacteria. A novel Hafnia phage, yong2, was induced from Hafnia paralvei by treatment with mitomycin C. The phage has an elliptical head with dimensions of approximately 45 × 38 nm and a long noncontractile tail of approximately 157 × 4 nm. The complete genome of Hafnia phage yong2 is a 39,546-bp double-stranded DNA with a G+C content of 49.9%, containing 59 open reading frames (ORFs) and having at least one fixed terminus (GGGGCAGCGACA). In phylogenetic analysis, Hafnia phage yong2 clustered with four predicted Hafnia prophages and one predicted Enterobacteriaceae prophage. These prophages and members of the family Drexlerviridae together formed two distinct subclades nested within a clade, suggesting the existence of a novel class of prophages with conserved sequences and a unique evolutionary status not yet studied before in Hafniaceae and Enterobacteriaceae bacteria.