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Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

Figueiredo R, Card R, Nunes C, AbuOun M, Bagnall MC, Nunez J, Mendonça N, Anjum MF, da Silva GJ - PLoS ONE (2015)

Bottom Line: Increased mortality of Galleria was detected on infection with Sal199 compared to LT2.This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans.Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy and Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Bacteriology, Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.

ABSTRACT
Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI) and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS) of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

No MeSH data available.


Related in: MedlinePlus

Adhesion and invasion of HT-29 cells by control strain S. Typhimurium LT2, S. Infantis Sal147, and S. Infantis Sal280.Data shown are means ± SEM from four independent experiments.
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pone.0135010.g003: Adhesion and invasion of HT-29 cells by control strain S. Typhimurium LT2, S. Infantis Sal147, and S. Infantis Sal280.Data shown are means ± SEM from four independent experiments.

Mentions: The arrays and WGS results predicted a difference in virulence between two S. Infantis strains tested, therefore we characterised these strains further by adhesion/invasion assays. From microarray and whole genome sequencing, one strain Sal147, has a large deletion in SPI-1 genes while Sal280 harboured all SPI-1 genes. The results of adhesion and invasion assays are shown in Fig 3. There was a statistically significant difference to the extent that S. Typhimurium LT2 control strain was able to adhere compared to both S. Infantis strains. In addition, S. Typhimurium LT2 was 2.6-fold more invasive in HT-29 cells than S. Infantis Sal280 (p < 0.001). When comparing the two S. Infantis strains no statistically significant difference in adhesion was observed, but S. Infantis Sal147, was unable to invade HT-29 cells, unlike Sal280 (p < 0.001; Fig 3).


Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

Figueiredo R, Card R, Nunes C, AbuOun M, Bagnall MC, Nunez J, Mendonça N, Anjum MF, da Silva GJ - PLoS ONE (2015)

Adhesion and invasion of HT-29 cells by control strain S. Typhimurium LT2, S. Infantis Sal147, and S. Infantis Sal280.Data shown are means ± SEM from four independent experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526557&req=5

pone.0135010.g003: Adhesion and invasion of HT-29 cells by control strain S. Typhimurium LT2, S. Infantis Sal147, and S. Infantis Sal280.Data shown are means ± SEM from four independent experiments.
Mentions: The arrays and WGS results predicted a difference in virulence between two S. Infantis strains tested, therefore we characterised these strains further by adhesion/invasion assays. From microarray and whole genome sequencing, one strain Sal147, has a large deletion in SPI-1 genes while Sal280 harboured all SPI-1 genes. The results of adhesion and invasion assays are shown in Fig 3. There was a statistically significant difference to the extent that S. Typhimurium LT2 control strain was able to adhere compared to both S. Infantis strains. In addition, S. Typhimurium LT2 was 2.6-fold more invasive in HT-29 cells than S. Infantis Sal280 (p < 0.001). When comparing the two S. Infantis strains no statistically significant difference in adhesion was observed, but S. Infantis Sal147, was unable to invade HT-29 cells, unlike Sal280 (p < 0.001; Fig 3).

Bottom Line: Increased mortality of Galleria was detected on infection with Sal199 compared to LT2.This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans.Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy and Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Bacteriology, Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.

ABSTRACT
Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI) and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS) of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

No MeSH data available.


Related in: MedlinePlus