Dataset Information

The mechanisms that regulate Vibrio parahaemolyticus virulence gene expression differ between pathotypes.

ABSTRACT: Most Vibrio parahaemolyticus isolates found in marine environments are non-pathogenic; however, certain lineages have acquired genomic pathogenicity islands (PAIs) that enable these isolates to cause human illness. The V. parahaemolyticus PAI contains one or both of two toxins: thermostable direct haemolysin (TDH) or TDH-related haemolysin (TRH) and type III secretion system 2 (T3SS2). Recently, a few V. parahaemolyticus isolates that do not have this PAI were obtained from clinical samples, and there has been interest in determining whether these isolates possess novel virulence factors. In this investigation, we have selected four V. parahaemolyticus isolates: a canonical pathogenic strain containing TDH, TRH and T3SS2; two strains from clinical cases which do not contain a PAI; and an environmental isolate which also does not contain a PAI. For each isolate, we analyzed differential gene expression after crude bile exposure. Several enteric bacterial pathogens are known to use bile as a signal to enhance virulence gene expression. We have shown that in the tdh-positive trh-positive pathotype gene virulence gene expression was not up-regulated in response to crude bile, strongly indicating that the current dogma of virulence gene regulation in V. parahaemolyticus needs to be revisited and separately investigated for each pathotype. In addition, we have created a list of genes of interest that were up-regulated in the non-canonical pathotypes which may contribute to virulence in these isolates.

SUBMITTER: Petronella N

PROVIDER: S-EPMC6096935 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The mechanisms that regulate Vibrio parahaemolyticus virulence gene expression differ between pathotypes.

Petronella Nicholas N Ronholm Jennifer J

Microbial genomics 20180529 6

Most Vibrio parahaemolyticus isolates found in marine environments are non-pathogenic; however, certain lineages have acquired genomic pathogenicity islands (PAIs) that enable these isolates to cause human illness. The V. parahaemolyticus PAI contains one or both of two toxins: thermostable direct haemolysin (TDH) or TDH-related haemolysin (TRH) and type III secretion system 2 (T3SS2). Recently, a few V. parahaemolyticus isolates that do not have this PAI were obtained from clinical samples, and ...[more]

PMID: 29813014

Similar Datasets

Project description:BackgroundVibrio parahaemolyticus is a common cause of foodborne disease. Beginning in 1996, a more virulent strain having serotype O3:K6 caused major outbreaks in India and other parts of the world, resulting in the emergence of a pandemic. Other serovariants of this strain emerged during its dissemination and together with the original O3:K6 were termed strains of the pandemic clone. Two genomes, one of this virulent strain and one pre-pandemic strain have been sequenced. We sequenced four additional genomes of V. parahaemolyticus in this study that were isolated from different geographical regions and time points. Comparative genomic analyses of six strains of V. parahaemolyticus isolated from Asia and Peru were performed in order to advance knowledge concerning the evolution of V. parahaemolyticus; specifically, the genetic changes contributing to serotype conversion and virulence. Two pre-pandemic strains and three pandemic strains, isolated from different geographical regions, were serotype O3:K6 and either toxin profiles (tdh+, trh-) or (tdh-, trh+). The sixth pandemic strain sequenced in this study was serotype O4:K68.ResultsGenomic analyses revealed that the trh+ and tdh+ strains had different types of pathogenicity islands and mobile elements as well as major structural differences between the tdh pathogenicity islands of the pre-pandemic and pandemic strains. In addition, the results of single nucleotide polymorphism (SNP) analysis showed that 94% of the SNPs between O3:K6 and O4:K68 pandemic isolates were within a 141 kb region surrounding the O- and K-antigen-encoding gene clusters. The "core" genes of V. parahaemolyticus were also compared to those of V. cholerae and V. vulnificus, in order to delineate differences between these three pathogenic species. Approximately one-half (49-59%) of each species' core genes were conserved in all three species, and 14-24% of the core genes were species-specific and in different functional categories.ConclusionsOur data support the idea that the pandemic strains are closely related and that recent South American outbreaks of foodborne disease caused by V. parahaemolyticus are closely linked to outbreaks in India. Serotype conversion from O3:K6 to O4:K68 was likely due to a recombination event involving a region much larger than the O-antigen- and K-antigen-encoding gene clusters. Major differences between pathogenicity islands and mobile elements are also likely driving the evolution of V. parahaemolyticus. In addition, our analyses categorized genes that may be useful in differentiating pathogenic Vibrios at the species level.

Dataset Information

The mechanisms that regulate Vibrio parahaemolyticus virulence gene expression differ between pathotypes.

Publications

The mechanisms that regulate Vibrio parahaemolyticus virulence gene expression differ between pathotypes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets