@article {12896,
	title = {Genome assortment, not serogroup, defines Vibrio cholerae pandemic strains},
	journal = {Nature},
	year = {2009},
	month = {2009///},
	abstract = {Vibrio cholerae, the causative agent of cholera, is a bacterium autochthonous to the aquatic environment, and a serious public health threat. V. cholerae serogroup O1 is responsible for the previous two cholera pandemics, in which classical and El Tor biotypes were dominant in the 6th and the current 7th pandemics, respectively. Cholera researchers continually face newly emerging and re-emerging pathogenic clones carrying combinations of new serogroups as well as of phenotypic and genotypic properties. These genotype and phenotype changes have hampered control of the disease. Here we compare the complete genome sequences of 23 strains of V. cholerae isolated from a variety of sources and geographical locations over the past 98 years in an effort to elucidate the evolutionary mechanisms governing genetic diversity and genesis of new pathogenic clones. The genome-based phylogeny revealed 12 distinct V. cholerae phyletic lineages, of which one, designated the V. cholerae core genome (CG), comprises both O1 classical and EI Tor biotypes. All 7th pandemic clones share nearly identical gene content, i.e., the same genome backbone. The transition from 6th to 7th pandemic strains is defined here as a {\textquoteright}shift{\textquoteright} between pathogenic clones belonging to the same O1 serogroup, but from significantly different phyletic lineages within the CG clade. In contrast, transition among clones during the present 7th pandemic period can be characterized as a {\textquoteright}drift{\textquoteright} between clones, differentiated mainly by varying composition of laterally transferred genomic islands, resulting in emergence of variants, exemplified by V.cholerae serogroup O139 and V.cholerae O1 El Tor hybrid clones that produce cholera toxin of classical biotype. Based on the comprehensive comparative genomics presented in this study it is concluded that V. cholerae undergoes extensive genetic recombination via lateral gene transfer, and, therefore, genome assortment, not serogroup, should be used to define pathogenic V. cholerae clones.},
	keywords = {59; CHOLERA; GENES; GENETICS; GENOTYPE; ISLANDS; ORIGIN; PHENOTYPE; PUBLIC HEALTH; RECOMBINATION; STRAINS; TOXINS},
	url = {http://www.osti.gov/energycitations/servlets/purl/962365-icnke9/},
	author = {Brettin,Thomas S[Los Alamos National Laboratory and Bruce,David C[Los Alamos National Laboratory and Challacombe,Jean F[Los Alamos National Laboratory and Detter,John C[Los Alamos National Laboratory and Han,Cliff S[Los Alamos National Laboratory and Munik,A. C[Los Alamos National Laboratory and Chertkov,Olga[Los Alamos National Laboratory and Meincke,Linda[Los Alamos National Laboratory and Saunders,Elizabeth[Los Alamos National Laboratory and Choi,Seon Y[SEOUL NATL UNIV and Haley,Bradd J[U MARYLAND and Taviani,Elisa[U MARYLAND and Jeon,Yoon-Seong[INTL VACCINE INST SEOUL and Kim,Dong Wook[INTL VACCINE INST SEOUL and Lee,Jae-Hak[SEOUL NATL UNIV and Walters,Ronald A[PNNL and Hug,Anwar[NATL INST CHOLERIC ENTERIC DIS and Rita R Colwell}
}
