A Rare, Virulent Bacteriophage Susfortuna Is the First Isolated Bacteriophage in a New Viral Genus.

is a well known swine pathogen. type A is considered the causative agent of enteric diseases in neonatal and weaned piglets. Phage therapy using phages has previously proved effective. Pig fecal samples were used to isolate phages, with type A as host. Complete genome sequencing, comparative genomics, a proteome analysis and electron microscopy were used to characterize the phage. Clostridium phage Susfortuna has a double-stranded DNA genome of 19,046 bp with a G+C% content of 29.2, inverted terminal repeats and 28 predicted coding sequences (CDSs). Putative functions could not be assigned to most of the CDSs (64.3%). Transmission electron microscopy of phage Susfortuna revealed an isometric head and a short protruding tail stub resembling the structure of the family. A proteome analysis of phage Susfortuna identified seven structural proteins, but only one could be assigned with a putative function. Based on the morphology, the inverted terminal repeats and the small genome size, phage Susfortuna belongs to subfamily within the family in the order . Together with bacteriophage CPD7, phage Susfortuna represent a new genus of bacteriophages with very limited DNA sequence similarity to other known phages. Despite the limited DNA sequence similarity, the gene synteny among putative structural genes of phage Susfortuna is conserved among several bacteriophages belonging to the family indicating a common ancestor.