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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

Virulence determinants microarrays data for 106 Salmonella strains analysed.At the top, the analysed genes are grouped according to their particular genomic location or function (fimbrial). The order of strains represents their relatedness according to the UPGMA dendrogram type performed in BioNumerics 5.1. The hybridization result of a distinct strain is shown by row. A white box indicates the absence and a black box indicates the presence of the target sequence in the strain.
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pone.0135010.g001: Virulence determinants microarrays data for 106 Salmonella strains analysed.At the top, the analysed genes are grouped according to their particular genomic location or function (fimbrial). The order of strains represents their relatedness according to the UPGMA dendrogram type performed in BioNumerics 5.1. The hybridization result of a distinct strain is shown by row. A white box indicates the absence and a black box indicates the presence of the target sequence in the strain.

Mentions: One hundred and eight probes and primers designed in this study for 105 genes were validated with control strains (S1 Table). Nine genes could not be validated as the probes were non-specific and have not been considered any further (data not shown). Microarray was performed on the aforementioned 106 Salmonella isolates. The microarray results were transformed to a binary form i.e. present or absent (S3 Table) and analysed in BioNumerics by an UPGMA cluster analysis (Fig 1). Cluster analysis showed four different clusters: one contained 20 isolates which were mainly from the non-common serotypes; one contained all S. Enteritidis isolates and there were two clusters of S. Typhimurium, one with 40 isolates without virulence plasmid and prophage associated genes and another comprising 20 isolates with these determinants (Fig 1).


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)

Virulence determinants microarrays data for 106 Salmonella strains analysed.At the top, the analysed genes are grouped according to their particular genomic location or function (fimbrial). The order of strains represents their relatedness according to the UPGMA dendrogram type performed in BioNumerics 5.1. The hybridization result of a distinct strain is shown by row. A white box indicates the absence and a black box indicates the presence of the target sequence in the strain.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0135010.g001: Virulence determinants microarrays data for 106 Salmonella strains analysed.At the top, the analysed genes are grouped according to their particular genomic location or function (fimbrial). The order of strains represents their relatedness according to the UPGMA dendrogram type performed in BioNumerics 5.1. The hybridization result of a distinct strain is shown by row. A white box indicates the absence and a black box indicates the presence of the target sequence in the strain.
Mentions: One hundred and eight probes and primers designed in this study for 105 genes were validated with control strains (S1 Table). Nine genes could not be validated as the probes were non-specific and have not been considered any further (data not shown). Microarray was performed on the aforementioned 106 Salmonella isolates. The microarray results were transformed to a binary form i.e. present or absent (S3 Table) and analysed in BioNumerics by an UPGMA cluster analysis (Fig 1). Cluster analysis showed four different clusters: one contained 20 isolates which were mainly from the non-common serotypes; one contained all S. Enteritidis isolates and there were two clusters of S. Typhimurium, one with 40 isolates without virulence plasmid and prophage associated genes and another comprising 20 isolates with these determinants (Fig 1).

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