Genetic Determinants and Polymorphisms Specific for Human-Adapted Serovars of
            <i>Salmonella enterica</i>
            That Cause Enteric Fever

Tracz, Dobryan M.; Tabor, Helen; Jerome, Morganne; Ng, Lai-King; Gilmour, Matthew W.

doi:10.1128/jcm.02630-05

Cited by 21 publications

(21 citation statements)

References 48 publications

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“…In contrast, other Salmonella serovars are host restricted and highly adapted in their pathogenesis. Salmonella enterica serovar Typhi, Salmonella enterica serovar Paratyphi A, and Salmonella enterica serovar Sendai are humanrestricted serovars and the causative agents of enteric fever (1,2). This is an invasive, life-threatening systemic disease with a global annual estimation of over 25 million cases, resulting in more than 200,000 deaths (3).…”

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confidence: 99%

Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

et al. 2015

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Salmonella enterica serovar Paratyphi A is a human-specific serovar that, together with Salmonella enterica serovar Typhi and Salmonella enterica serovar Sendai, causes enteric fever. Unlike the nontyphoidal Salmonella enterica serovar Typhimurium, the genomes of S. Typhi and S. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype of S. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidal S. Typhi, S. Paratyphi A, and S. Sendai are all noticeably less motile than S. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that in S. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than in S. Typhimurium. Nevertheless, S. Paratyphi A, like S. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that in S. Paratyphi A, but not in S. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and the Salmonella pathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 in S. Paratyphi A that does not occur in S. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellumchemotaxis regulon between these clinically relevant pathogens. Salmonella enterica is one of the most prevalent human and animal pathogens, consisting of more than 2,500 serovars. Some Salmonella serovars, such as Salmonella enterica serovar Typhimurium, are ubiquitous pathogens that can infect a broad range of animal and human hosts. In contrast, other Salmonella serovars are host restricted and highly adapted in their pathogenesis. Salmonella enterica serovar Typhi, Salmonella enterica serovar Paratyphi A, and Salmonella enterica serovar Sendai are humanrestricted serovars and the causative agents of enteric fever (1, 2). This is an invasive, life-threatening systemic disease with a global annual estimation of over 25 million cases, resulting in more than 200,000 deaths (3). In recent years, the occurrence of infection with S. Paratyphi A has been rising, and in some regions of the world (particularly in eastern and southern Asia), it is accountable for up to 50% of all enteric fever cases (4, 5). Increasing rates of infection, the lack of a commercially available vaccine, and steadily increasing resistance of S. Paratyphi A isolates to antimicrobial agents make S. Paratyphi A infections a significant public health concern.Bacterial invasion of nonphagocytic cells is one of the hallmarks of S. enterica and is pivotal for its pathogenicity. Active invasion by Salmonella of eukaryotic ...

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Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

et al. 2015

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“…Here we have concentrated on one of the alternatives, PCR. Similar DNA-based strategies to detect and identify Salmonella isolates have been explored in the past (5,7,9,10,12,13,19,38). These protocols usually rely on exact matches of oligonucleotide sequences.…”

Section: Discussionmentioning

confidence: 99%

“…L, DNA size standard. (8,38) have been explored for typing purposes. This technology may in the future replace serology when targeted at the O-and H-antigen gene clusters.…”

Section: Discussionmentioning

confidence: 99%

“…These include pulsed-field gel electrophoresis (14,33,35), multilocus enzyme electrophoresis (34), variable-number-of-tandem-repeat analysis (2,37), and multilocus sequence typing (6,36). In addition, several PCR-based methods were investigated, targeting genes specific to some or all salmonellae (7,9,10,17,19,38). Recent approaches using multiplex PCR are based on variable numbers of probes, ranging from 7 to 12 (13,17).…”

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Salmonella Serovar Identification Using PCR-Based Detection of Gene Presence and Absence

et al. 2008

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There are more than 2,500 known Salmonella serovars, and some of these can be further subclassified into groups of strains that differ profoundly in their gene content. We refer to these groups of strains as "genovars." A compilation of comparative genomic hybridization data on 291 Salmonella isolates, including 250 S. enterica subspecies I strains from 32 serovars (52 genovars), was used to select a panel of 384 genes whose presence and absence among serovars and genovars was of potential taxonomic value. A subset of 146 genes was used for real-time PCR to successfully identify 12 serovars (16 genovars) in 24 S. enterica strains. A further subset of 64 genes was used to identify 8 serovars (9 genovars) in 12 multiplex PCR mixes on 11 S. enterica strains. These gene panels distinguish all tested S. enterica subspecies I serovars and their known genovars, almost all by two or more informative markers. Thus, a typing methodology based on these predictive genes would generally alert users if there is an error, an unexpected polymorphism, or a potential new genovar.

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“…1,2 These symptoms are actually closely related to the flagellum. The flagellum extends from the cell membrane to form a helical propeller that enables the thallus to migrate to more favorable environments.…”

Section: Introductionmentioning

confidence: 99%

High Specific DNAzyme-Aptamer Sensor for Salmonella paratyphi A Using Single-Walled Nanotubes–Based Dual Fluorescence-Spectrophotometric Methods

Ning

Duan

et al. 2014

SLAS Discovery

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In this work, single-stranded DNA aptamers that are highly specific to enterotoxigenic Salmonella paratyphi A were obtained from an enriched oligonucleotide pool using Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to target the flagellin protein. The selected aptamers were confirmed to have high sensitivity and specificity to the flagellin. In addition, a probe (P0) containing the DNAzyme and fluorescein isothiocyanate-labeled aptamer3 sequences was employed as a dual probe for observing fluorescence and absorbance changes. The flagellin demonstrated low detection limits of 5 ng/mL by fluorescence and 20 ng/mL by spectrophotometry. Moreover, milk samples spiked with Salmonella paratyphi A were also detected, with the low detection limits increasing to 10 5 CFU/mL by fluorescence and 10 6 CFU/mL by spectrophotometry. The combination of fluorescence and spectrophotometry offers a specific, rapid, and sensitive way for detecting Salmonella paratyphi A and has potential for detecting other pathogens in food.

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Genetic Determinants and Polymorphisms Specific for Human-Adapted Serovars of Salmonella enterica That Cause Enteric Fever

Cited by 21 publications

References 48 publications

Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

Salmonella Serovar Identification Using PCR-Based Detection of Gene Presence and Absence

High Specific DNAzyme-Aptamer Sensor for Salmonella paratyphi A Using Single-Walled Nanotubes–Based Dual Fluorescence-Spectrophotometric Methods

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