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A multiplex real-time PCR assay targeting virulence and resistance genes in Salmonella enterica serotype Typhimurium.

ABSTRACT: BACKGROUND: Typhimurium is the main serotype of Salmonella enterica subsp. enterica implicated in food-borne diseases worldwide. This study aimed to detect the prevalence of ten markers combined in a macro-array based on multiplex real-time PCR. We targeted characteristic determinants located on pathogenicity islands (SPI-2 to -5, virulence plasmid pSLT and Salmonella genomic island 1 (SGI1)) as well as a specific 16S-23S rRNA intergenic spacer sequence of definitive type 104 (DT104). To investigate antimicrobial resistance, the study also targeted the presence of genes involved in sulfonamide (sul1) and beta-lactam (blaTEM) resistance. Finally, the intI1 determinant encoding integrase from class 1 integron was also investigated. RESULTS: A total of 538 unrelated S. Typhimurium strains isolated between 1999 and 2009 from various sources, including food animals, food products, human and environmental samples were studied. Based on the combined presence or absence of these markers, we distinguished 34 different genotypes, including three major genotypes encountered in 75% of the studied strains, Although SPI determinants were almost always detected, SGI1, intI1, sul1 and blaTEM determinants were found 47%, 52%, 54% and 12% of the time respectively, varying according to isolation source. Low-marker patterns were most often detected in poultry sources whereas full-marker patterns were observed in pig, cattle and human sources. CONCLUSION: The GeneDisc® assay developed in this study madeit easier to explore variability within serotype Typhimurium by analyzing ten relevant gene determinants in a large collection of strains. This real-time multiplex method constitutes a valuable tool for strains characterization on epidemiological purposes.

SUBMITTER: Bugarel M

PROVIDER: S-EPMC3150258 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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A multiplex real-time PCR assay targeting virulence and resistance genes in Salmonella enterica serotype Typhimurium.

Bugarel Marie M Granier Sophie A SA Weill François-Xavier FX Fach Patrick P Brisabois Anne A

BMC microbiology 20110627

<h4>Background</h4>Typhimurium is the main serotype of Salmonella enterica subsp. enterica implicated in food-borne diseases worldwide. This study aimed to detect the prevalence of ten markers combined in a macro-array based on multiplex real-time PCR. We targeted characteristic determinants located on pathogenicity islands (SPI-2 to -5, virulence plasmid pSLT and Salmonella genomic island 1 (SGI1)) as well as a specific 16S-23S rRNA intergenic spacer sequence of definitive type 104 (DT104). To ...[more]

PMID: 21707966

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Project description:Regulation of flagellum biosynthesis is a hierarchical process that is tightly controlled to allow for efficient tuning of flagellar expression. Flagellum-mediated motility directs Salmonella enterica serovar Typhimurium toward the epithelial surface to enhance gut colonization, but flagella are potent activators of innate immune signaling, so fine-tuning flagellar expression is necessary for immune avoidance. In this work, we evaluate the role of the LysR transcriptional regulator YeiE in regulating flagellum-mediated motility. We show that yeiE is necessary and sufficient for swimming motility. A ΔyeiE mutant is defective for gut colonization in both the calf ligated ileal loop model and the murine colitis model due to its lack of motility. Expression of flagellar class 2 and 3 but not class 1 genes is reduced in the ΔyeiE mutant. We linked the motility dysregulation of the ΔyeiE mutant to repression of the anti-FlhD4C2 factor STM1697. Together, our results indicate that YeiE promotes virulence by enhancing cell motility, thereby providing a new regulatory control point for flagellar expression in Salmonella Typhimurium. IMPORTANCE The ability to finely tune virulence factor gene expression is required for bacterial pathogens to successfully colonize a host. Flagellum-mediated motility is critical for many gut pathogens to establish productive infections. However, flagella activate the immune system, leading to bacterial clearance; therefore, tight control of flagellar gene expression enhances bacterial fitness in the host. Here, we demonstrate that the transcriptional regulator YeiE acts as a control point for flagellar gene expression and is required for Salmonella Typhimurium to establish a productive infection in mammals. The expression of an inhibitor of flagellar biogenesis is repressed in the absence of yeiE. Our work adds a new layer to the tightly controlled cascade regulating control of flagellar gene expression to facilitate the fitness of an enteric pathogen.

Dataset Information

A multiplex real-time PCR assay targeting virulence and resistance genes in Salmonella enterica serotype Typhimurium.

Publications

A multiplex real-time PCR assay targeting virulence and resistance genes in Salmonella enterica serotype Typhimurium.

Similar Datasets

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