A Taxonomic Review of Clostridium difficile Phages and Proposal of a Novel Genus, Phimmp04likevirus

Currently, only three phages that infect the medically important bacterium Clostridium difficile have been discussed by the International Committee of Viral Taxonomy (ICTV). They are all myoviruses, and have been assigned to the genus phicd119likevirus. An additional nine phages have since been described in the literature with their genome data available. The Phicd119likevirus is named after the type species: the myovirus phi CD119 which was the first C. difficile phage to be sequenced. The two additional myoviruses, phi CD27 and phi C2, also fall into this genus based on the similarity of their genome and morphological characteristics. The other nine phages have not been assigned to this genus, and four of them do not fit the criteria for the current taxonomic grouping. We have applied protein clustering analysis to determine their phylogenetic relationships. From these results we propose an additional myoviridae genus, that we term phiMMP04likevirus.