Family: Herelleviridae

Subfamily: Twortvirinae

Distinguishing features

Members of this subfamily generally infect Staphylococcus strains, have low GC content (about 30%), and have genomes of 127–153 kbp (Kvachadze et al., 2011, Łobocka et al., 2012, Barylski et al., 2020).

Genus demarcation criteria

Members of different Twortvirinae genera belong to different well-supported monophyletic clades in genome-based phylogenies and in (concatenated) marker gene phylogenies. Members of the same genus share at least 60% nucleotide identity across the genome length. The genome organisation is conserved. Members of the same genus generally infect members of the same bacterial genus. Note that the genus Harbinvirus had been misplaced in the subfamily Twortvirinae; the Taxonomic Proposal 2020.072B.R.Herelleviridae (https://ictv.global/taxonomy/taxondetails?taxnode_id=202107399 ) changed its status to an orphan genus in the Herelleviridae family.