Presence of typical and atypical virulence genes in vibrio isolates belonging to the Harveyi clade

Ruwandeepika, H. A. D.; Defoirdt, Tom; Bhowmick, Patit Paban; Shekar, Malathi; Bossier, Peter; Karunasagar, Iddya

doi:10.1111/j.1365-2672.2010.04715.x

Cited by 64 publications

(58 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was proposed that such pathogeninduced blooms drive conjugative horizontal gene transfer between different Enterobacteriaceae and are responsible for the evolution of both pathogens and commensals. Thus, the human intestinal tract may represent an ecological niche that stimulates the occurrence of horizontal gene transfer both among different strains of V. parahaemolyticus and between V. parahaemolyticus and other commensal species (65)(66)(67)(68). What remains unknown is the frequency of such evolutionary events, although it is likely to be relatively low.…”

Section: Discussionmentioning

confidence: 99%

Genetic Relationships of Vibrio parahaemolyticus Isolates from Clinical, Human Carrier, and Environmental Sources in Thailand, Determined by Multilocus Sequence Analysis

Theethakaew

Feil

Castillo-Ramírez

et al. 2013

Appl Environ Microbiol

View full text Add to dashboard Cite

e Vibrio parahaemolyticus is a seafood-borne pathogenic bacterium that is a major cause of gastroenteritis worldwide. We investigated the genetic and evolutionary relationships of 101 V. parahaemolyticus isolates originating from clinical, human carrier, and various environmental and seafood production sources in Thailand using multilocus sequence analysis. The isolates were recovered from clinical samples (n ‫؍‬ 15), healthy human carriers (n ‫؍‬ 18), various types of fresh seafood (n ‫؍‬ 18), frozen shrimp (n ‫؍‬ 16), fresh-farmed shrimp tissue (n ‫؍‬ 18), and shrimp farm water (n ‫؍‬ 16). Phylogenetic analysis revealed a high degree of genetic diversity within the V. parahaemolyticus population, although isolates recovered from clinical samples and from farmed shrimp and water samples represented distinct clusters. The tight clustering of the clinical isolates suggests that disease-causing isolates are not a random sample of the environmental reservoir, although the source of infection remains unclear. Extensive serotypic diversity occurred among isolates representing the same sequence types and recovered from the same source at the same time. These findings suggest that the O-and K-antigen-encoding loci are subject to exceptionally high rates of recombination. There was also strong evidence of interspecies horizontal gene transfer and intragenic recombination involving the recA locus in a large proportion of isolates. As the majority of the intragenic recombinational exchanges involving recA occurred among clinical and carrier isolates, it is possible that the human intestinal tract serves as a potential reservoir of donor and recipient strains that is promoting horizontal DNA transfer, driving evolutionary change, and leading to the emergence of new, potentially pathogenic strains. Vibrio parahaemolyticus is a seafood-borne pathogenic bacterium and is the leading cause of traveler's diarrhea and gastroenteritis worldwide due to the consumption of undercooked contaminated seafood, particularly shellfish. The organism possesses a number of virulence factors, including a thermostable direct hemolysin (TDH) (1), a thermostable direct hemolysinrelated hemolysin (TRH) (2), and type 3 secretion system 1 (TTSS1) and TTSS2 (3). Strains that possess tdh, trh, and TTSS2-encoding genes are generally pathogenic and responsible for the vast majority of clinical cases. While such strains account for only 1 to 2% of isolates sampled from water and different marine species (4-6), they are known to have a widespread global distribution, having been reported from cases of infection in Japan, India, Thailand, Malaysia, China, Indonesia, the United Kingdom, Italy, and the East and Gulf Coasts of the United States (7-19).The public health and commercial burdens associated with V. parahaemolyticus contamination are very high in Thailand due to the wide consumption of seafood. Although undercooked seafood has been identified as a source of V. parahaemolyticus infection (20, 21), the relative likelihood of contamination from differ...

show abstract

Section: Discussionmentioning

confidence: 99%

Genetic Relationships of Vibrio parahaemolyticus Isolates from Clinical, Human Carrier, and Environmental Sources in Thailand, Determined by Multilocus Sequence Analysis

Theethakaew

Feil

Castillo-Ramírez

et al. 2013

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…We found that the genomes of several species of Vibrio whose genomes have been completely sequenced encode homologues of HlyA in chromosome II, with identity values at the amino acid level ranging from 47% to 50%. These Vibrio species include V. cholerae (23), V. anguillarum (24), V. fluvialis (25), V. furnissii (26), and V. harveyi (27), among others.…”

Section: Resultsmentioning

confidence: 99%

Synergistic and Additive Effects of Chromosomal and Plasmid-Encoded Hemolysins Contribute to Hemolysis and Virulence in Photobacterium damselae subsp. damselae

et al. 2013

View full text Add to dashboard Cite

Photobacterium damselae subsp. damselae causes infections and fatal disease in marine animals and in humans. Highly hemolytic strains produce damselysin (Dly) and plasmid-encoded HlyA (HlyA pl ). These hemolysins are encoded by plasmid pPHDD1 and contribute to hemolysis and virulence for fish and mice. In this study, we report that all the hemolytic strains produce a hitherto uncharacterized chromosome-encoded HlyA (HlyA ch ). Hemolysis was completely abolished in a single hlyA ch mutant of a plasmidless strain and in a dly hlyA pl hlyA ch triple mutant. We found that Dly, HlyA pl , and HlyA ch are needed for full hemolytic values in strains harboring pPHDD1, and these values are the result of the additive effects between HlyA pl and HlyA ch , on the one hand, and of the synergistic effect of Dly with HlyA pl and HlyA ch , on the other hand. Interestingly, Dly-producing strains produced synergistic effects with strains lacking Dly production but secreting HlyA, constituting a case of the CAMP (Christie, Atkins, and Munch-Petersen) reaction. Environmental factors such as iron starvation and salt concentration were found to regulate the expression of the three hemolysins. We found that the contributions, in terms of the individual and combined effects, of the three hemolysins to hemolysis and virulence varied depending on the animal species tested. While Dly and HlyA pl were found to be main contributors in the virulence for mice, we observed that the contribution of hemolysins to virulence for fish was mainly based on the synergistic effects between Dly and either of the two HlyA hemolysins rather than on their individual effects.

show abstract

“…1990). Importantly, pathogenicity appears not to be species dependent, but rather a strain characteristic as some strains belonging to one specific species can be highly pathogenic, whereas other strains are avirulent (Austin & Zhang 2006; Ruwandeepika et al. 2010).…”

Section: Impact Of Vibriosis Caused By Harveyi Clade Vibrios On the Amentioning

confidence: 99%

Pathogenesis, virulence factors and virulence regulation of vibrios belonging to the Harveyi clade

Ruwandeepika

Jayaweera

Bhowmick

et al. 2012

Reviews in Aquaculture

127

View full text Add to dashboard Cite

The Harveyi clade or core group of the Vibrio genus includes both pathogenic and non-pathogenic bacteria. Some of the species belonging to the clade, such as Vibrio harveyi, Vibrio alginolyticus, Vibrio campbellii and Vibrio parahaemolyticus, include serious pathogens of aquatic organisms. Importantly, within these species, some strains are pathogenic, whereas others are not. Other members of the clade, such as Vibrio natriegens and Vibrio mytili are reported to be non-pathogenic. As bacteria belonging to the Harveyi clade show a high diversity with respect to virulence and as the virulent members cause high mortalities in the aquaculture sector, it is important to understand which gene products are responsible for the pathogenicity of the bacteria and how expression of these virulence factors is regulated. This knowledge will ultimately allow for the development of biocontrol measures that aim to reduce the severe losses that are currently faced in the aquaculture sector as a result of vibriosis. In this review, we discuss the pathogenesis of bacteria belonging to the Harveyi clade, their impact on the aquaculture sector, the virulence factors that are involved in pathogenicity and their regulation

show abstract

Presence of typical and atypical virulence genes in vibrio isolates belonging to the Harveyi clade

Cited by 64 publications

References 64 publications

Genetic Relationships of Vibrio parahaemolyticus Isolates from Clinical, Human Carrier, and Environmental Sources in Thailand, Determined by Multilocus Sequence Analysis

Genetic Relationships of Vibrio parahaemolyticus Isolates from Clinical, Human Carrier, and Environmental Sources in Thailand, Determined by Multilocus Sequence Analysis

Synergistic and Additive Effects of Chromosomal and Plasmid-Encoded Hemolysins Contribute to Hemolysis and Virulence in Photobacterium damselae subsp. damselae

Pathogenesis, virulence factors and virulence regulation of vibrios belonging to the Harveyi clade

Contact Info

Product

Resources

About