Family: Inoviridae

Genus: Affertcholeramvirus

Distinguishing features

The genome of the exemplar isolate Vibrio phage CTXphi of the species Vibrio virus CTXphi is about 7 kb with G+C = 45%. The genome contains two regions: the RS2 region (rstR, rstA and rstB - replication, regulation, and integration) and the core region [psh, cep, orfU (gIII), ace, zot and ctxAB] (Waldor et al., 1997). Vibrio phage CTXphi integrates into the chromosome of V. cholerae at the attB (dif) integration site and in some strains appears as a tandem repeat. Vibrio phage CTXphi carries three genes for toxin production: ace (accessory cholera enterotoxin) which is a minor coat protein, zot (zonula occludens toxin) responsible for maturation and ctxAB without a known function in the phage replication cycle, but whose product is the cholera A-B enterotoxin (CT). These genes are part of a virulence cassette of V. cholera O1 and O139 serogroups (Faruque and Mekalanos 2012). 

Virion

See discussion under family description. 

Genome organisation and replication

See discussion under family description. 

Biology

Members of this genus infect Vibrio cholerae.  

Species demarcation criteria

There is only one species in the genus. Members of additional species will be >5% different in the DNA sequence of their genomes as assessed using the BLASTn algorithm.