title: High prevalence and diversity of pre-CTXΦ alleles in the environmental Vibrio cholerae O1 and O139 strains in the Zhujiang River estuary.
abstract: Toxigenic conversion of environmental Vibrio cholerae strains through lysogenic infection by the phage CTXΦ is an important step in the emergence of new pathogenic clones. The precursor form of the CTXΦ phage, pre-CTXΦ, does not carry the cholera toxin gene. During our investigation, we frequently found pre-CTXΦ prophages in non-toxigenic isolates in the serogroups of O1 and O139 strains in the Zhujiang estuary. We observed high amounts of sequence variation of rstR and gIII(CTX) in the pre-CTXΦ alleles as well as in the tcpA sequences within the strains. In addition, a new pre-CTXΦ allele, with a novel rstR sequence type and hybrid RS2, was identified. Our findings show that active, complicated gene recombination and horizontal transfer of pre-CTXΦs occurs within V. cholerae environmental strains, which creates a complex intermediate pool for the generation of toxigenic clones in the estuarine environment.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Guangzhou, China.
authors.forename: Duochun
authors.initials: D
authors.lastname: Wang
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
authors.forename: Baisheng
authors.initials: B
authors.lastname: Li
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Deng
authors.forename: Hailing
authors.initials: H
authors.lastname: Tan
authors.forename: Baowei
authors.initials: B
authors.lastname: Diao
authors.forename: Jingdiao
authors.initials: J
authors.lastname: Chen
authors.forename: Bixia
authors.initials: B
authors.lastname: Ke
authors.forename: Haojie
authors.initials: H
authors.lastname: Zhong
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhou
authors.forename: Changwen
authors.initials: C
authors.lastname: Ke
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
mesh_terms: D000483:Alleles; D001483:Base Sequence; D004783:Environmental Microbiology; D019143:Evolution, Molecular; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics; D023061:Gene Order; D005814:Genes, Viral; D014644:Genetic Variation; D016679:Genome, Viral; D008969:Molecular Sequence Data; D010802:Phylogeny; D039002:Prophages / Q000235:genetics*; D041241:Vibrio cholerae O1 / Q000145:classification / Q000235:genetics* / Q000821:virology*; D041242:Vibrio cholerae O139 / Q000145:classification / Q000235:genetics* / Q000821:virology*
chemical_list: C085807:TcpA protein, Vibrio cholerae; D036781:Fimbriae Proteins