Abstract:

Objective: To understand the group structure and clonal complex of worldwide environmental Vibrio
parahaemolyticus strains. Methods: Worldwide environmental V. parahaemolyticus strains with complete sequence types (ST)
and peptide sequence types (pST) were screened from the PubMLST public database, the subgroup analysis and complex
analysis was conducted, and the minimum spanning tree was established based on ST and pST types. Results: From the
database, 886 items were screened for analyzing the ST and pST types of worldwide environmental V. parahaemolyticus
strains, which belonged to 663 ST types with ST3 type being the most dominant, but only containing information on
27 strains. Out of these, 436 items came from China (including mainland, Hong Kong and Taiwan), including 410 ST types,
each of which contained information on 1– 4 strains and these 436 strains could be divided into 128 pST types, with pST1
type being the most dominant type, containing information on 116 strains. The eBURST software was used to analyze the
data and 73 groups and 483 singletons were observed. Analysis with the software STRUCTURE showed that appropriate
subset number of global V. parahaemolyticus strains was 4, and the average distance between samples in each subgroup was
0.981 7. Conclusion: Worldwide environmental V. parahaemolyticus strains in Asia are characterized by high polymorphism
and can be subdivided into 4 subgroups. ST3 type is the most dominant strain when MLST typing is used while pST1 type is
the most dominant strain by AA-MLST typing.

Key words: Vibrio parahaemolyticus, multilocus sequence typing, peptide based multilocus sequence typing, clonal complex