The Evolution of the Vibrio cholerae Genome during the Modern Period

A review of the modern data concerning the phenotypical and genetic peculiarities of the recently emerged highly virulent variants of V. cholerae El-Tor biovar (the etiological agent of the current cholera pandemic) is presented. The molecular-genetic mechanisms that are considered to be a basis for V. cholerae genome evolution during the modern period are discussed. The transposon role in the increased expression of cholera toxin genes, which are constituents of the CTX phi prophage genome, is addressed. The need to work out new gene-diagnostic test-systems for the identification of natural altered variants of the cholera etiological agent is shown.