Three phages are involved in cholera disease caused by Vibrio cholerae

Vibrio cholerae is a gram negative, facultative aerobic and comma shaped bacterium causing cholera. It causes deadly, infectious diarrhoeal disease occur. Patient who suffers from this kind of disease may loss up to 20 liters of electrolyte per day. Pathogenicity Island has an important role in bacterial pathogenicity.

Three Phages that are involved in the cause of cholera disease by Vibrio cholera are given here:

CTXφ contains the genes for the two subunits of cholera toxin. It is known to be basically bacteriophage genome integrated into the bacterial chromosome. CTXφ is a filamentous phage that infects Vibrio cholerae. It requires the TcpA pilus as receptor and is usually integrated as a prophage into the bacterial chromosome.

VPI expresses TcpA, the capsid protein of the virus and the subunit of the Toxin coregulated pilus (TCP) that is required for colonization of the epithelium (direct binding of epithelial cells). VPIφ seems to be a filamentous phage by itself. It is presented as a prophage in the cell (integrated into the genome)

RS1 is a satellite phage that promotes transmission of CTXφ by expression of the anti- repressor RstC. RS1 can only infect cells already infected with CTXφ, since it lacks important replication as well as the capsid protein. It will use the CTXφ capsid protein to pack its own genome.