title: Origin of Vibrio parahaemolyticus O3:K6 pandemic clone.
abstract: O3:K6 pandemic clone of Vibrio parahaemolyticus has caused outbreaks in coastal countries since 1996. Mutilocus sequence typing (MLST) is an important tool to trace the source and analysis the evolution of bacteria. Based on MLST, the first pandemic clonal complex (CC) of V. parahaemolyticus has been confirmed. In this study, 57 pandemic strains, 27 pathogenic strains (tdh or trh positive) and 36 nonpathogenic strains isolated from China were analyzed with MLST. Forty-seven unique sequence types, one clonal complex (CC) and one doublet (D) were identified by eBURST and Mega4 analyses. CC corresponded to not only the known O3:K6 pandemic clone (including ST-3, ST-192, ST-227) but nonpathogenic clone (including ST-3, S-T2, ST-196, ST-220, ST-226). ST-3 was the founder of the complex. STs of the isolates were not inevitably associated with the presence or number of the accessory genes or the serotypes of the isolates. The ancestor strain of O3:K6 pandemic clone was originated from an environmental nonpathogenic O3:K6, ST-3 strain. The pandemic O3:K6 clone was developed from this strain in approximately 1996 by laterally transferring large fragments of genes including systematic functional genes and genomic islands.
authors.affiliation: Yangzhou University, Yangzhou 225009, China.
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Chao
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhou
authors.forename: Xinan
authors.initials: X
authors.lastname: Jiao
authors.forename: Jinlin
authors.initials: J
authors.lastname: Huang
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Pan
authors.forename: Liping
authors.initials: L
authors.lastname: Zhou
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Qian
mesh_terms: D015373:Bacterial Typing Techniques; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D044404:Genomic Islands; D058885:Multilocus Sequence Typing; D058873:Pandemics; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014735:Vibrio Infections / Q000453:epidemiology / Q000382:microbiology; D014736:Vibrio parahaemolyticus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial