Family: Inoviridae
Genus: Saetivirus
Distinguishing features
Phages in the genus Saetivirus possess genomes of about 8.5 kb (44% G+C) and virions are 7 nm in width and 1,200 nm (Vibrio phage fs2) to 1,400 nm (Vibrio phage VFJ) in length. Vibrio phage fs2 was isolated from Vibrio cholerae O139 and is able to integrate into host genome using host integration enzymes; infected strains show reduced pili expression on the cell surface. Virions are resistant to treatment at 70oC for 10 minutes, but sensitive to treatment at 80oC for 10 minutes or to chloroform (Ikema and Honma 1998, Nguyen et al., 2008). The classical biotype of V. cholerae O1 serogroup shows a high level of resistance to infection. The integration of Vibrio phage VFJ into the bacterial chromosome has not been confirmed, but after infection bacteria decrease growth rate and flagella production, acquire a low level of resistance to ampicillin and high resistance to kanamycin (Wang et al., 2013).
Virion
See discussion under family description.
Genome organisation and replication
See discussion under family description.
Biology
Members of the genus infect bacteria from the genus Vibrio.
Species demarcation criteria
Members of different species are >5% different in the DNA sequence of their genomes as assessed using the BLASTn algorithm.