Prevalence and genetic diversity of clinical Vibrio parahaemolyticus isolates from China, revealed by multilocus sequence typing scheme

Abstract

The population structure of clinical Vibrio parahaemolyticus isolates spreading in China remains undefined. We brought 218 clinical isolates from the pubMLST database originating from different regions of China collected since the year of 1990, analyzed by multilocus sequence typing (MLST), to elucidate the prevalence and genetic diversity of V. parahaemolyticus circulating in Chinese population. The MLST scheme produced 137 sequence types (STs). These STs were clustered into six clonal complexes (CCs), six doublets, and 91 singletons, exhibiting a high level of genetic diversity. However, less diversity was displayed on the peptide level: only 46 different peptide sequence type (pST) were generated, with pST2 (44.0%, 96/218) and pST1 (15.1%, 33/218) the predominant. Further analysis confirmed all the pSTs belong to a single complex founded by pST1, pST2, pST3, and pST4. recA presented the highest degree of nucleotide diversity (0.026) and the largest number of variable sites (176) on the nucleotide level. pyrC was the most diverse locus on the peptide level, possessing the highest percentage of variable sites (9.2%, 15/163). Significant linkage disequilibrium with the alleles was detected when the Standardized Index of Association (ISA) was calculated both for the entire isolates collection (0.7169, P < 0.01) and for the 137 STs (ISA = 0.2648, P < 0.01). In conclusion, we provide an overview of prevalence and genetic diversity of clinical V. parahaemolyticus spreading in Chinese population using MLST analysis. The results would offer genetic evidences for uncovering the microevolution relationship of V. parahaemolyticus populations.

Sero-Prevalence and Genetic Diversity of Pandemic V. parahaemolyticus Strains Occurring at a Global Scale

“…In the present study, we showed that the population structure of V. parahaemolyticus was extremely genetically diverse based on the successful identification of 19 CCs and a large number of singletons, in agreement with previous findings (Han et al, 2015 ). Over half of the pandemic STs belonged to CC3 according to goeBURST analysis.…”

“…In previous studies, we successfully made extensive descriptions of strains from a global clinical collection and from Chinese patients, respectively, exhibiting a highly degree of genetic diversity and a complicated population structure of V. parahaemolyticus in general (Han et al, 2014 , 2015 ). In this study, we elucidated the sero-prevalence and genetic differentiation of the pandemic clone, which has becoming an emerging public health concern (Martinez-Urtaza et al, 2010 ; Velazquez-Roman et al, 2012 , 2014 ; Powell et al, 2013 ; Li et al, 2014 ; Pazhani et al, 2014 ).…”

“…The establishment of a multilocus sequence typing (MLST) scheme for V. parahaemolyticus has enhanced our knowledge of the population structure and genetic diversity of V. parahaemolyticus (Gonzalez-Escalona et al, 2008 ). Previous studies based on MLST assay have shown that the increasing prevalence of clonal complex 3 (CC3) has become an ongoing public health concern (Gonzalez-Escalona et al, 2008 ; Haendiges et al, 2014 ; Han et al, 2015 ), and most pandemic strains have been identified as belonging to CC3 (Chen et al, 2016 ). Thus, clarifying the genetic diversity among the pandemic strains will aid in the selection of preventative strategies targeting pandemic strain infections.…”

Genetic and Population Analyses of Vibrio Parahaemolyticus Isolates from Three Major Coastal Regions in China

“…The gyrB locus was the most diverse, with 87 alleles, while possessing only 63 (10.6%) variable sites. This is consistent with the findings of previous studies [ 18 , 19 ]. The dN/dS values of each locus were all lower than 1.0, revealing that these loci had been subjected to purifying selection [ 24 ].…”

“…Previous studies already used MLST analysis to characterize V. parahaemolyticus strains, and some researchers also evaluated the epidemiology of this pathogen in China [ 18 ]. The strains used in some studies had a global distribution [ 19 , 20 ], with a focus being placed on both clinical and environmental isolates [ 21 ].…”