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Sample records for enterica serovar typhimurium

  1. Draft Genome Sequences of Salmonella enterica subsp. enterica Serovars Typhimurium and Nottingham Isolated from Food Products

    PubMed Central

    Zheng, Jie; Ayers, Sherry; Melka, David C.; Curry, Phillip E.; Payne, Justin S.; Laasri, Anna; Wang, Charles; Hammack, Thomas S.; Brown, Eric W.

    2016-01-01

    A quantitative real-time PCR (qPCR) designed to detect Salmonella enterica subsp. enterica serovar Enteritidis, targeting the sdf gene, generated positive results for S. enterica subsp. enterica serovar Typhimurium (CFSAN033950) and S. enterica subsp. enterica serovar Nottingham (CFSAN006803) isolated from food samples. Both strains show pulsed-field gel electrophoresis (PFGE) patterns distinct from those of S. Enteritidis. Here, we report the genome sequences of these two strains. PMID:27445384

  2. Intestinal Cytokine Responses to Salmonella enterica Serovar Typhimurium Infection in Young Chicks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar typhimurium is one of the most frequently isolated strains in human salmonellosis worldwide, and is commonly found in broilers. Successful prevention and control of Salmonella colonization in poultry require better understanding of intestinal mucosal immune response to ...

  3. Gene Transfer between Salmonella enterica Serovar Typhimurium inside Epithelial Cells

    PubMed Central

    Ferguson, Gayle C.; Heinemann, Jack A.; Kennedy, Martin A.

    2002-01-01

    Virulence and antibiotic resistance genes transfer between bacteria by bacterial conjugation. Conjugation also mediates gene transfer from bacteria to eukaryotic organisms, including yeast and human cells. Predicting when and where genes transfer by conjugation could enhance our understanding of the risks involved in the release of genetically modified organisms, including those being developed for use as vaccines. We report here that Salmonella enterica serovar Typhimurium conjugated inside cultured human cells. The DNA transfer from donor to recipient bacteria was proportional to the probability that the two types of bacteria occupied the same cell, which was dependent on viable and invasive bacteria and on plasmid tra genes. Based on the high frequencies of gene transfer between bacteria inside human cells, we suggest that such gene transfers occur in situ. The implications of gene transfer between bacteria inside human cells, particularly in the context of antibiotic resistance, are discussed. PMID:11914355

  4. Clustered Intracellular Salmonella enterica Serovar Typhimurium Blocks Host Cell Cytokinesis

    PubMed Central

    Durkin, Charlotte H.; Helaine, Sophie; Boucrot, Emmanuel

    2016-01-01

    Several bacterial pathogens and viruses interfere with the cell cycle of their host cells to enhance virulence. This is especially apparent in bacteria that colonize the gut epithelium, where inhibition of the cell cycle of infected cells enhances the intestinal colonization. We found that intracellular Salmonella enterica serovar Typhimurium induced the binucleation of a large proportion of epithelial cells by 14 h postinvasion and that the effect was dependent on an intact Salmonella pathogenicity island 2 (SPI-2) type 3 secretion system. The SPI-2 effectors SseF and SseG were required to induce binucleation. SseF and SseG are known to maintain microcolonies of Salmonella-containing vacuoles close to the microtubule organizing center of infected epithelial cells. During host cell division, these clustered microcolonies prevented the correct localization of members of the chromosomal passenger complex and mitotic kinesin-like protein 1 and consequently prevented cytokinesis. Tetraploidy, arising from a cytokinesis defect, is known to have a deleterious effect on subsequent cell divisions, resulting in either chromosomal instabilities or cell cycle arrest. In infected mice, proliferation of small intestinal epithelial cells was compromised in an SseF/SseG-dependent manner, suggesting that cytokinesis failure caused by S. Typhimurium delays epithelial cell turnover in the intestine. PMID:27185791

  5. Epidemiology of a Salmonella enterica subsp. enterica serovar Typhimurium strain associated with a songbird outbreak.

    PubMed

    Hernandez, Sonia M; Keel, Kevin; Sanchez, Susan; Trees, Eija; Gerner-Smidt, Peter; Adams, Jennifer K; Cheng, Ying; Ray, Al; Martin, Gordon; Presotto, Andrea; Ruder, Mark G; Brown, Justin; Blehert, David S; Cottrell, Walter; Maurer, John J

    2012-10-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast. PMID:22885752

  6. Epidemiology of a Salmonella enterica subsp. Enterica serovar Typhimurium strain associated with a songbird outbreak.

    USGS Publications Warehouse

    Blehert, David S.; Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; Peter Gerner-Smidt

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  7. THE POXR GENE OF SALMONELLA ENTERICA SEROVAR TYPHIMURIUM IS INVOLVED IN STRESS SURVIVAL AND SWINE COLONIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mutations in the poxR gene (STM4344; yjeA; poxA) of Salmonella enterica serovar Typhimurium (S. Typhimurium) have previously been shown to cause several phenotypic alterations including reduced pyruvate oxidase activity, virulence attenuation in the mouse model, and enhanced sensitivity to various ...

  8. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the present study were to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three mutants on the smoo...

  9. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium

    PubMed Central

    Park, Sun-Yang; Pontes, Mauricio H.; Groisman, Eduardo A.

    2015-01-01

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg2+. This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg2+ transporter, an inhibitor of Salmonella’s own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg2+ media but not in low Mg2+ liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg2+ semisolid environments. PMID:25624475

  10. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium.

    PubMed

    Park, Sun-Yang; Pontes, Mauricio H; Groisman, Eduardo A

    2015-02-10

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg(2+). This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg(2+) transporter, an inhibitor of Salmonella's own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg(2+) media but not in low Mg(2+) liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg(2+) semisolid environments. PMID:25624475

  11. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    DOE PAGESBeta

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Ussery, David W.; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; et al

    2016-03-04

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. In this paper, we used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ~1948 (95% credible interval [CI], 1934more » to 1962) and later became MDR DT104 in ~1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ~1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. Finally, the results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.« less

  12. Stress Response of Salmonella enterica Serovar Typhimurium to Acidified Nitrite

    PubMed Central

    Mühlig, Anna; Behr, Jürgen; Scherer, Siegfried

    2014-01-01

    The antimicrobial action of the curing agent sodium nitrite (NaNO2), which is added as a preservative to raw meat products, depends on its conversion to nitric oxide and other reactive nitrogen species under acidic conditions. In this study, we used RNA sequencing to analyze the acidified-NaNO2 shock and adaptive responses of Salmonella enterica serovar Typhimurium, a frequent contaminant in raw meat, considering parameters relevant for the production of raw-cured sausages. Upon a 10-min exposure to 150 mg/liter NaNO2 in LB (pH 5.5) acidified with lactic acid, genes involved in nitrosative-stress protection, together with several other stress-related genes, were induced. In contrast, genes involved in translation, transcription, replication, and motility were downregulated. The induction of stress tolerance and the reduction of cell proliferation obviously promote survival under harsh acidified-NaNO2 stress. The subsequent adaptive response was characterized by upregulation of NsrR-regulated genes and iron uptake systems and by downregulation of genes involved in anaerobic respiratory pathways. Strikingly, amino acid decarboxylase systems, which contribute to acid tolerance, displayed increased transcript levels in response to acidified NaNO2. The induction of systems known to be involved in acid resistance indicates a nitrite-mediated increase in the level of acid stress. Deletion of cadA, which encodes lysine decarboxylase, resulted in increased sensitivity to acidified NaNO2. Intracellular pH measurements using a pH-sensitive green fluorescent protein (GFP) variant showed that the cytoplasmic pH of S. Typhimurium in LB medium (pH 5.5) is decreased upon the addition of NaNO2. This study provides the first evidence that intracellular acidification is an additional antibacterial mode of action of acidified NaNO2. PMID:25107963

  13. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    PubMed Central

    Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; Aarestrup, Frank M.

    2016-01-01

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections. PMID:26944846

  14. Complete genome sequence of Salmonella enterica serovar typhimurium bacteriophage SPN1S.

    PubMed

    Shin, Hakdong; Lee, Ju-Hoon; Lim, Jeong-A; Kim, Hyeryen; Ryu, Sangryeol

    2012-01-01

    To understand the interaction between the host of pathogenic Salmonella enterica serovar Typhimurium and its bacteriophage, we isolated the bacteriophage SPN1S. It is a lysogenic phage in the Podoviridae family and uses the O-antigen of lipopolysaccharides (LPS) as a host receptor. Comparative genomic analysis of phage SPN1S and the S. enterica serovar Anatum-specific phage ε15 revealed different host specificities, probably due to the low homology of host specificity-related genes. Here we report the complete circular genome sequence of S. Typhimurium-specific bacteriophage SPN1S and show the results of our analysis. PMID:22205721

  15. Internal Colonization of Salmonella enterica Serovar Typhimurium in Tomato Plants

    PubMed Central

    Gu, Ganyu; Hu, Jiahuai; Cevallos-Cevallos, Juan M.; Richardson, Susanna M.; Bartz, Jerry A.; van Bruggen, Ariena H. C.

    2011-01-01

    Several Salmonella enterica outbreaks have been traced back to contaminated tomatoes. In this study, the internalization of S. enterica Typhimurium via tomato leaves was investigated as affected by surfactants and bacterial rdar morphotype, which was reported to be important for the environmental persistence and attachment of Salmonella to plants. Surfactants, especially Silwet L-77, promoted ingress and survival of S. enterica Typhimurium in tomato leaves. In each of two experiments, 84 tomato plants were inoculated two to four times before fruiting with GFP-labeled S. enterica Typhimurium strain MAE110 (with rdar morphotype) or MAE119 (without rdar). For each inoculation, single leaflets were dipped in 109 CFU/ml Salmonella suspension with Silwet L-77. Inoculated and adjacent leaflets were tested for Salmonella survival for 3 weeks after each inoculation. The surface and pulp of ripe fruits produced on these plants were also examined for Salmonella. Populations of both Salmonella strains in inoculated leaflets decreased during 2 weeks after inoculation but remained unchanged (at about 104 CFU/g) in week 3. Populations of MAE110 were significantly higher (P<0.05) than those of MAE119 from day 3 after inoculation. In the first year, nine fruits collected from one of the 42 MAE119 inoculated plants were positive for S. enterica Typhimurium. In the second year, Salmonella was detected in adjacent non-inoculated leaves of eight tomato plants (five inoculated with strain MAE110). The pulp of 12 fruits from two plants inoculated with MAE110 was Salmonella positive (about 106 CFU/g). Internalization was confirmed by fluorescence and confocal laser microscopy. For the first time, convincing evidence is presented that S. enterica can move inside tomato plants grown in natural field soil and colonize fruits at high levels without inducing any symptoms, except for a slight reduction in plant growth. PMID:22096553

  16. Tetracycline promotes the expression of ten fimbrial operons in specific Salmonella enterica serovar Typhimurium isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans and presents an important food safety concern. Antibiotic resistance among isolates of Salmonella enterica serovar Typhimurium has become especially prevalent as over 27 per cent of isolates from humans in the Unit...

  17. Polynucleotide phosphorlyase (PNPase) is required for Salmonella enterica serovar Typhimurium colonization in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for survival in...

  18. PORCINE DIFFERENTIAL GENE EXPRESSION IN RESPONSE TO SALMONELLA ENTERICA SEROVARS CHOLERAESUIS AND TYPHIMURIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using suppression subtractive hybridization (SSH) and real-time PCR, an investigation of the porcine response to infection with Salmonella enterica serovars Choleraesuis (narrow host range) and Typhimurium (broad host range) revealed different transcriptional profiles. Ten genes identified by SSH a...

  19. GLOBAL TRANSCRIPTIONAL RESPONSE OF PORCINE MESENTERIC LYMPH NODES TO SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonellosis is prevalent worldwide and is both a food safety and animal production problem. To understand the host transcriptional response to Salmonella enterica serovar Typhimurium, the Affymetrix GeneChip® porcine genome array was used to identify differentially expressed (DE) genes in mesente...

  20. Hydrogen-Stimulated carbon acquisition and conservation in salmonella enterica serovar typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium can utilize molecular hydrogen for growth and amino acid transport during anaerobic growth. Via microarray we identified H2 gas-affected gene expression changes in Salmonella. Addition of H2 caused altered expression of 965 genes; 176 genes were H2-up-regulate...

  1. Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100% glucose with 2-linked glucose as the most abundant residue with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structu...

  2. Antibiotics induce the expression of attachment genes in specific isolates of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 27 percent of Salmonella enterica serovar Typhimurium isolates from humans in the United States are resistant to three or more antibiotics. This presents an important food safety concern as multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans. It has been...

  3. Early immune response following Salmonella enterica subspecies enterica serovar Typhimurium infection in porcine jejunal gut loops.

    PubMed

    Meurens, François; Berri, Mustapha; Auray, Gael; Melo, Sandrine; Levast, Benoît; Virlogeux-Payant, Isabelle; Chevaleyre, Claire; Gerdts, Volker; Salmon, Henri

    2009-01-01

    Salmonella enterica subspecies enterica serovar Typhimurium, commonly called S. Typhimurium, can cause intestinal infections in humans and various animal species such as swine. To analyze the host response to Salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. Four jejunal gut-loops were each inoculated with 3 x 10(8) cfu of S. Typhimurium in 3 one-month-old piglets and mRNA expressions of various cytokines, chemokines, transcription factors, antimicrobial peptides, toll like and chemokine receptors were assessed by quantitative real-time PCR in the Peyer's patch and the gut wall after 24 h. Several genes such as the newly cloned CCRL1/CCX-CKR were assessed for the first time in the pig at the mRNA level. Pro-inflammatory and T-helper type-1 (Th1) cytokine mRNA were expressed at higher levels in infected compared to non-infected control loops. Similarly, some B cell activation genes, NOD2 and toll like receptor 2 and 4 transcripts were more expressed in both tissues while TLR5 mRNA was down-regulated. Interestingly, CCL25 mRNA expression as well as the mRNA expressions of its receptors CCR9 and CCRL1 were decreased both in the Peyer's patch and gut wall suggesting a potential Salmonella strategy to reduce lymphocyte homing to the intestine. In conclusion, these results provide insight into the porcine innate mucosal immune response to infection with entero-invasive microorganisms such as S. Typhimurium. In the future, this knowledge should help in the development of improved prophylactic and therapeutic approaches against porcine intestinal S. Typhimurium infections. PMID:18922229

  4. Analysis of antimicrobial resistance genes detected in multidrug-resistant salmonella enterica serovar typhimurium isolated from food animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of multi drug resistance (MDR) in foodborne pathogens such as Salmonella enterica is a concern for both animal and human health. MDR Salmonella enterica serovar Typhimurium is the most prevalent penta-resistant serovar isolated from animals as part of the National Antimicrobial Resis...

  5. Host Transmission of Salmonella enterica Serovar Typhimurium Is Controlled by Virulence Factors and Indigenous Intestinal Microbiota▿

    PubMed Central

    Lawley, Trevor D.; Bouley, Donna M.; Hoy, Yana E.; Gerke, Christine; Relman, David A.; Monack, Denise M.

    2008-01-01

    Transmission is an essential stage of a pathogen's life cycle and remains poorly understood. We describe here a model in which persistently infected 129X1/SvJ mice provide a natural model of Salmonella enterica serovar Typhimurium transmission. In this model only a subset of the infected mice, termed supershedders, shed high levels (>108 CFU/g) of Salmonella serovar Typhimurium in their feces and, as a result, rapidly transmit infection. While most Salmonella serovar Typhimurium-infected mice show signs of intestinal inflammation, only supershedder mice develop colitis. Development of the supershedder phenotype depends on the virulence determinants Salmonella pathogenicity islands 1 and 2, and it is characterized by mucosal invasion and, importantly, high luminal abundance of Salmonella serovar Typhimurium within the colon. Immunosuppression of infected mice does not induce the supershedder phenotype, demonstrating that the immune response is not the main determinant of Salmonella serovar Typhimurium levels within the colon. In contrast, treatment of mice with antibiotics that alter the health-associated indigenous intestinal microbiota rapidly induces the supershedder phenotype in infected mice and predisposes uninfected mice to the supershedder phenotype for several days. These results demonstrate that the intestinal microbiota plays a critical role in controlling Salmonella serovar Typhimurium infection, disease, and transmissibility. This novel model should facilitate the study of host, pathogen, and intestinal microbiota factors that contribute to infectious disease transmission. PMID:17967858

  6. Refined Live Attenuated Salmonella enterica Serovar Typhimurium and Enteritidis Vaccines Mediate Homologous and Heterologous Serogroup Protection in Mice

    PubMed Central

    Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F.; Galen, James E.; Levine, Myron M.

    2015-01-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  7. Refined live attenuated Salmonella enterica serovar Typhimurium and Enteritidis vaccines mediate homologous and heterologous serogroup protection in mice.

    PubMed

    Tennant, Sharon M; Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F; Galen, James E; Levine, Myron M

    2015-12-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  8. Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Associates with CRISPR Sequence Type

    PubMed Central

    DiMarzio, Michael; Shariat, Nikki; Kariyawasam, Subhashinie; Barrangou, Rodolphe

    2013-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is a leading cause of food-borne salmonellosis in the United States. The number of antibiotic-resistant isolates identified in humans is steadily increasing, suggesting that the spread of antibiotic-resistant strains is a major threat to public health. S. Typhimurium is commonly identified in a wide range of animal hosts, food sources, and environments, but little is known about the factors mediating the spread of antibiotic resistance in this ecologically complex serovar. Previously, we developed a subtyping method, CRISPR–multi-virulence-locus sequence typing (MVLST), which discriminates among strains of several common S. enterica serovars. Here, CRISPR-MVLST identified 22 sequence types within a collection of 76 S. Typhimurium isolates from a variety of animal sources throughout central Pennsylvania. Six of the sequence types were identified in more than one isolate, and we observed statistically significant differences in resistance among these sequence types to 7 antibiotics commonly used in veterinary and human medicine, such as ceftiofur and ampicillin (P < 0.05). Importantly, five of these sequence types were subsequently identified in human clinical isolates, and a subset of these isolates had identical antibiotic resistance patterns, suggesting that these subpopulations are being transmitted through the food system. Therefore, CRISPR-MVLST is a promising subtyping method for monitoring the farm-to-fork spread of antibiotic resistance in S. Typhimurium. PMID:23796925

  9. Salmonella enterica Serovar Typhimurium and Escherichia coli Contamination of Root and Leaf Vegetables Grown in Soils with Incorporated Bovine Manure

    PubMed Central

    Natvig, Erin E.; Ingham, Steven C.; Ingham, Barbara H.; Cooperband, Leslie R.; Roper, Teryl R.

    2002-01-01

    Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P ≥ 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10°C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum

  10. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature

    PubMed Central

    Singh, Atul K.; Drolia, Rishi; Bai, Xingjian; Bhunia, Arun K.

    2015-01-01

    We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125–250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25–5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25–50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods. PMID:26252374

  11. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature.

    PubMed

    Singh, Atul K; Drolia, Rishi; Bai, Xingjian; Bhunia, Arun K

    2015-01-01

    We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125-250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25-5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25-50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods. PMID:26252374

  12. Differences in the motility phenotype of multidrug-resistant Salmonella enterica serovar Typhimurium exposed to various antibiotics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most prevalent foodborne-associated bacteria in humans and livestock, and over 35 per cent of these isolates are resistant to three or more antibiotics. This is a concern as multidrug-resistant (MDR) Salmonella has been associat...

  13. Assessment of antibiotic resistance phenotype and integrons in Salmonella enterica serovar Typhimurium isolated from swine.

    PubMed

    Rayamajhi, Nabin; Kang, Sang Gyun; Kang, Mi Lan; Lee, Hee Soo; Park, Kyung Yoon; Yoo, Han Sang

    2008-10-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) isolated and identified from swine were subjected for the analysis of antibiotic resistance pattern and clinically important class 1 and 2 integrons. In addition, S. Typhimurium isolates exhibiting ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline and florfenicol (ACSSuTF) resistance pattern as described in most Salmonella enterica serotype Typhimurium definitive type 104 (DT104) were characterized by polymerase chain reaction. All the isolates were resistant to more than four antibiotics and showed the highest resistance to streptomycin (94.1%), followed by tetracycline (90.1%), ampicillin (64.7%), chloramphenicol (56.8%) and gentamicin (54.9%). MIC value for the ten isolates ranged between 0.125-2 mug/ml for ciprofloxacin. Among the beta-lactams used, only one of the isolate exhibited resistance to ceftiofur (MIC 8 microg/ml). Sixty eight percent of these multi drug resistance (MDR) S. Typhimurium isolates carried clinically important class 1 integron with 1kb (aadA) and/or 2kb (dhfrXII-orfF-aadA2) resistance gene cassettes. This study reports the increasing trend of multi drug resistance (MDR) S. Typhimurium with clinically important class 1 integron in pigs. In addition, emergence of the ACSSuTF-type resistance in S. Typhimurium PT other than DT104 may limit the use of resistance gene markers in its detection methods by PCR. PMID:18981675

  14. Neutrophils Are a Source of Gamma Interferon during Acute Salmonella enterica Serovar Typhimurium Colitis

    PubMed Central

    Spees, Alanna M.; Kingsbury, Dawn D.; Wangdi, Tamding; Xavier, Mariana N.; Tsolis, Renée M.

    2014-01-01

    Gamma interferon (IFN-γ) is an important driver of intestinal inflammation during colitis caused by Salmonella enterica serovar Typhimurium. Here we used the mouse colitis model to investigate the cellular sources of IFN-γ in the cecal mucosa during the acute phase of an S. Typhimurium infection. While IFN-γ staining was detected in T cells, NK cells, and inflammatory monocytes at 2 days after infection, the majority of IFN-γ-positive cells in the cecal mucosa were neutrophils. Furthermore, neutrophil depletion blunted mucosal Ifng expression and reduced the severity of intestinal lesions during S. Typhimurium infection. We conclude that neutrophils are a prominent cellular source of IFN-γ during the innate phase of S. Typhimurium-induced colitis. PMID:24421037

  15. Regulation of fucose and 1,2-propanediol utilization by Salmonella enterica serovar Typhimurium

    PubMed Central

    Staib, Lena; Fuchs, Thilo M.

    2015-01-01

    After ingestion, Salmonella enterica serovar Typhimurium (S. Typhimurium) encounters a densely populated, competitive environment in the gastrointestinal tract. To escape nutrient limitation caused by the intestinal microbiota, this pathogen has acquired specific metabolic traits to use compounds that are not metabolized by the commensal bacteria. For example, the utilization of 1,2-propanediol (1,2-PD), a product of the fermentation of L-fucose, which is present in foods of herbal origin and is also a terminal sugar of gut mucins. Under anaerobic conditions and in the presence of tetrathionate, 1,2-PD can serve as an energy source for S. Typhimurium. Comprehensive database analysis revealed that the 1,2-PD and fucose utilization operons are present in all S. enterica serovars sequenced thus far. The operon, consisting of 21 genes, is expressed as a single polycistronic mRNA. As demonstrated here, 1,2-PD was formed and further used when S. Typhimurium strain 14028 was grown with L-fucose, and the gene fucA encoding L-fuculose-1-phosphate aldolase was required for this growth. Using promoter fusions, we monitored the expression of the propanediol utilization operon that was induced at very low concentrations of 1,2-PD and was inhibited by the presence of D-glucose. PMID:26528264

  16. Global Transcriptome and Mutagenic Analyses of the Acid Tolerance Response of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Ryan, Daniel; Pati, Niladri Bhusan; Ojha, Urmesh K.; Padhi, Chandrashekhar; Ray, Shilpa; Jaiswal, Sangeeta; Singh, Gajinder P.; Mannala, Gopala K.; Schultze, Tilman; Chakraborty, Trinad

    2015-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than −1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K+ binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject. PMID:26386064

  17. An infection-relevant transcriptomic compendium for Salmonella enterica Serovar Typhimurium.

    PubMed

    Kröger, Carsten; Colgan, Aoife; Srikumar, Shabarinath; Händler, Kristian; Sivasankaran, Sathesh K; Hammarlöf, Disa L; Canals, Rocío; Grissom, Joe E; Conway, Tyrrell; Hokamp, Karsten; Hinton, Jay C D

    2013-12-11

    Bacterial transcriptional networks consist of hundreds of transcription factors and thousands of promoters. However, the true complexity of transcription in a bacterial pathogen and the effect of the environments encountered during infection remain to be established. We present a simplified approach for global promoter identification in bacteria using RNA-seq-based transcriptomic analyses of 22 distinct infection-relevant environmental conditions. Individual RNA samples were combined to identify most of the 3,838 Salmonella enterica serovar Typhimurium promoters in just two RNA-seq runs. Individual in vitro conditions stimulated characteristic transcriptional signatures, and the suite of 22 conditions induced transcription of 86% of all S. Typhimurium genes. We highlight the environmental conditions that induce the Salmonella pathogenicity islands and present a small RNA expression landscape of 280 sRNAs. This publicly available compendium of environmentally controlled expression of every transcriptional feature of S. Typhimurium constitutes a useful resource for the bacterial research community. PMID:24331466

  18. Characterization of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from pigs presenting with diarrhea in Korea

    PubMed Central

    LEE, Ki-Eun; LEE, Deog-Yong; CHOI, Hwan-Won; CHAE, Su-Jin; YUN, Young-Sun; LEE, Ki-Chan; CHO, Yun-Sang; YANG, Dong-Kun

    2015-01-01

    Between 2011 and 2012, a total of 896 pig fecal samples were collected from nine provinces in Korea, and 50 salmonella enterica susp. enterica serovar Typhimurium (S. Typhimurium) was isolated. The characteristics of the 50 strains were analyzed, and 4 strains were identified as Salmonella enterica subsp. enterica serovar 4,[5],12:i:-. Salmonella 4,[5],12:i:- could not be distinguished from S. Typhimurium through phage typing, antimicrobial resistance testing or multiple-locus variable-number tandem repeat analysis (MLVA). However, among the four Salmonella 4,[5],12:i:- strains, one (KVCC-BA1400078) was identified as a Salmonella 4,[5],12:i:- clone isolated from humans in the United States, and another (KVCC-BA1400080) was identified as DT193, which has been primarily isolated from humans and animals in European countries. The presence of Salmonella 4,[5],12:i:- in Korea poses a significant threat of horizontal transfer between pigs and humans. PMID:26074410

  19. Antibody Is Required for Protection against Virulent but Not Attenuated Salmonella enterica Serovar Typhimurium

    PubMed Central

    McSorley, Stephen J.; Jenkins, Marc K.

    2000-01-01

    Resolution of infection with attenuated Salmonella is an active process that requires CD4+ T cells. Here, we demonstrate that costimulation via the surface molecule CD28, but not antibody production by B cells, is required for clearance of attenuated aroA Salmonella enterica serovar typhimurium. In contrast, specific antibody is critical for vaccine-induced protection against virulent bacteria. Therefore, CD28+ CD4+ T cells are sufficient for clearance of avirulent Salmonella in naive hosts, whereas CD4+ T cells and specific antibodies are required for protection from virulent Salmonella in immune hosts. PMID:10816483

  20. H2-M3 Major Histocompatibility Complex Class Ib-Restricted CD8 T Cells Induced by Salmonella enterica Serovar Typhimurium Infection Recognize Proteins Released by Salmonella Serovar Typhimurium

    PubMed Central

    Ugrinovic, S.; Brooks, C. G.; Robson, J.; Blacklaws, B. A.; Hormaeche, C. E.; Robinson, J. H.

    2005-01-01

    Salmonella enterica serovar Typhimurium causes a typhoid-like disease in mice which has been studied extensively as a model for typhoid fever in humans. CD8 T cells contribute to protection against S. enterica serovar Typhimurium in mice, but little is known about the specificity and major histocompatibility complex (MHC) restriction of the response. We report here that CD8 T-cell lines derived from S. enterica serovar Typhimurium-infected BALB/c mice lysed bone marrow macrophages infected with S. enterica serovar Typhimurium or pulsed with proteins from S. enterica serovar Typhimurium culture supernatants. Cytoxicity was beta-2-microglobulin dependent and largely TAP dependent, although not MHC class Ia restricted, as target cells of several different MHC haplotypes were lysed. The data suggested the participation of class Ib MHC molecules although no evidence for the presence of Qa1-restricted T cells could be found, unlike in previous reports. Instead, the T-cell lines lysed H2-M3-transfected fibroblasts infected with S. enterica serovar Typhimurium SL3261 or treated with Salmonella culture supernatants. Thus, this report increases the number of MHC class Ib antigen-presenting molecules known for Salmonella antigens to three: Qa-1, HLA-E, and now H2-M3. It also expands the range of pathogens that induce H2-M3-restricted CD8 T cells to include an example of gram-negative bacteria. PMID:16299293

  1. Genomic Variability of Serial Human Isolates of Salmonella enterica Serovar Typhimurium Associated with Prolonged Carriage

    PubMed Central

    Octavia, Sophie; Wang, Qinning; Tanaka, Mark M.

    2015-01-01

    Salmonella enterica serovar Typhimurium is an important foodborne human pathogen that often causes self-limiting but severe gastroenteritis. Prolonged excretion of S. Typhimurium after the infection can lead to secondary transmissions. However, little is known about within-host genomic variation in bacteria associated with asymptomatic shedding. Genomes of 35 longitudinal isolates of S. Typhimurium recovered from 11 patients (children and adults) with culture-confirmed gastroenteritis were sequenced. There were three or four isolates obtained from each patient. Single nucleotide polymorphisms (SNPs) were analyzed in these isolates, which were recovered between 1 and 279 days after the initial diagnosis. Limited genomic variation (5 SNPs or fewer) was associated with short- and long-term carriage of S. Typhimurium. None of the isolates was shown to be due to reinfection. SNPs occurred randomly, and the majority of the SNPs were nonsynonymous. Two nonsense mutations were observed. A nonsense mutation in flhC rendered the isolate nonmotile, whereas the significance of a nonsense mutation in yihV is unknown. The estimated mutation rate is 1.49 × 10−6 substitution per site per year. S. Typhimurium isolates excreted in stools following acute gastroenteritis in children and adults demonstrated limited genomic variability over time, regardless of the duration of carriage. These findings have important implications for the detection of possible transmission events suspected by public health genomic surveillance of S. Typhimurium infections. PMID:26311853

  2. Deletion of Invasion Protein B in Salmonella enterica Serovar Typhimurium Influences Bacterial Invasion and Virulence.

    PubMed

    Chen, Songbiao; Zhang, Chunjie; Liao, Chengshui; Li, Jing; Yu, Chuan; Cheng, Xiangchao; Yu, Zuhua; Zhang, Mingliang; Wang, Yang

    2015-12-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) has a wide host range and causes infections ranging from severe gastroenteritis to systemic infections in human, as well as causing typhoid-like disease in murine models of infection. S. Typhimurium translocates its effector proteins through the Salmonella pathogenicity island-I (SPI-I)-encoded T3SS-I needle complex. This study focuses on invasion protein B (SipB) of S. Typhimurium, which plays an active role in SPI-I invasion efficiency. To test our hypothesis, a sipB deletion mutant was constructed through double-crossover allelic using the suicide vector pRE112ΔsipB, and its biological characteristics were analyzed. The results showed that the SipB does not affect the growth of Salmonella, but the adherence, invasion, and virulence of the mutant were significantly decreased compared with wild-type S. Typhimurium (SL1344). This research indicates that SipB is an important virulence factor in the pathogenicity of S. Typhimurium. PMID:26341924

  3. Requirement for cobalamin by Salmonella enterica serovars Typhimurium, Pullorum, Gallinarum and Enteritidis during infection in chickens

    PubMed Central

    Vaz, Jacqueline Boldrin; Penha Filho, Rafael Antonio Casarin; Junior, Angelo Berchieri; Lemos, Manoel Victor Franco

    2011-01-01

    Salmonella enterica serovar Typhimurium synthesizes cobalamin (vitamin B12) only during anaerobiosis. Two percent of the S. Typhimurium genome is devoted to the synthesis and uptake of vitamin B12 and to B12-dependent reactions. To understand the requirement for cobalamin synthesis better, we constructed mutants of Salmonella serovars Enteritidis and Pullorum that are double-defective in cobalamin biosynthesis (ΔcobSΔcbiA). We compared the virulence of these mutants to that of their respective wild type strains and found no impairment in their ability to cause disease in chickens. We then assessed B12 production in these mutants and their respective wild type strains, as well as in S. Typhimurium ΔcobSΔcbiA, Salmonella Gallinarum ΔcobSΔcbiA, and their respective wild type strains. None of the mutants was able to produce detectable B12. B12 was detectable in S. Enteritidis, S. Pullorum and S. Typhimurium wild type strains but not in S. Gallinarum. In conclusion, the production of vitamin B12in vitro differed across the tested Salmonella serotypes and the deletion of the cbiA and cobS genes resulted in different levels of alteration in the host parasite interaction according to Salmonella serotype tested. PMID:24031771

  4. Characteristics of Salmonella enterica Serovar 4,[5],12:i:- as a Monophasic Variant of Serovar Typhimurium

    PubMed Central

    Ido, Noriko; Lee, Ken-ichi; Iwabuchi, Kaori; Izumiya, Hidemasa; Uchida, Ikuo; Kusumoto, Masahiro; Iwata, Taketoshi; Ohnishi, Makoto; Akiba, Masato

    2014-01-01

    Salmonella enterica subspecies enterica serovar 4,[5],12:i:- (S. 4,[5]12:i:-) is believed to be a monophasic variant of S. enterica serovar Typhimurium (S. Typhimurium). This study was conducted to corroborate this hypothesis and to identify the molecular and phenotypic characteristics of the S. 4,[5]12:i:- isolates in Japan. A total of 51 S. 4,[5]12:i:- isolates derived from humans, cattle, swine, chickens, birds, meat (pork), and river water in 15 prefectures in Japan between 2000 and 2010 were analyzed. All the S. 4,[5],12:i:- isolates were identified as S. Typhimurium by two different polymerase chain reactions (PCR) for identification of S. Typhimurium. Of the 51 S. 4,[5],12:i:- isolates, 39 (76.5%) harbored a 94-kb virulence plasmid, which is known to be specific for S. Typhimurium. These data suggest that the S. 4,[5],12:i:- isolates are monophasic variants of S. Typhimurium. The flagellar phase variation is induced by three adjacent genes (fljA, fljB, and hin) in the chromosome. The results of PCR mapping of this region and comparative genomic hybridization analysis suggested that the deletion of the fljAB operon and its flanking region was the major genetic basis of the monophasic phenotype of S. 4,[5],12:i:-. The fljAB operon and hin gene were detectable in eight of the S. 4,[5],12:i:- isolates with common amino acid substitutions of A46T in FljA and R140L in Hin. The introduction of these mutations into S. Typhimurium isolates led to the loss of selectability of isolates expressing the phase 2 H antigen. These data suggested that a point mutation was the genetic basis, at least in part, of the S. 4,[5],12:i:- isolates. The results of phenotypic analysis suggested that the S. 4,[5],12:i:- isolates in Japan consist of multiple distinct clones. This is the first detailed characterization of the S. 4,[5],12:i:- isolates derived from various sources across Japan. PMID:25093666

  5. Inactivation of Salmonella enterica serovar Typhimurium and quality maintenance of cherry tomatoes treated with gaseous essential oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antimicrobial activity of the essential oils (EOs) from cinnamon bark, oregano, mustard and of their major components cinnamaldehyde, carvacrol, and allyl isothiocyanate (AIT) were evaluated as a gaseous treatment to reduce Salmonella enterica serovar Typhimurium in vitro and on tomatoes. In dif...

  6. sciS, an icmF Homolog in Salmonella enterica Serovar Typhimurium, Limits Intracellular Replication and Decreases Virulence

    PubMed Central

    Parsons, Duncan A.; Heffron, Fred

    2005-01-01

    Salmonella enterica serovar Typhimurium utilizes macrophages to disseminate from the intestine to deeper tissues within the body. While S. enterica serovar Typhimurium has been shown to kill its host macrophage, it can persist intracellularly beyond 18 h postinfection. To identify factors involved in late stages of infection, we screened a transposon library made in S. enterica serovar Typhimurium for the ability to persist in J774 macrophages at 24 h postinfection. Through this screen, we identified a gene, sciS, found to be homologous to icmF in Legionella pneumophila. icmF, which is required for intracellular multiplication, is conserved in several gram-negative pathogens, and its homolog appears to have been acquired horizontally in S. enterica serovar Typhimurium. We found that an sciS mutant displayed increased intracellular numbers in J774 macrophages when compared to the wild-type strain at 24 h postinfection. sciS was maximally transcribed at 27 h postinfection and is repressed by SsrB, an activator of genes required for promoting intracellular survival. Finally, we demonstrate that an sciS mutant is hypervirulent in mice when administered intragastrically. Taken together, these data indicate a role for SciS in controlling intracellular bacterial levels at later stages of infection and attenuating virulence in a murine host PMID:15972528

  7. Molecular profiling: Catecholamine modulation of gene expression in Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Investigations of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various ...

  8. A mutation in the pnp gene encoding polynucleotide phosphorylase attenuates virulence of Salmonella enterica serovar typhimurium in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for ...

  9. The alternate sigma factor RpoS protects against silver ion toxicity in Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The alternative sigma factor, RpoS controls the expression of many stress response genes, including genes involved in acid and oxidative stresses. In this study, we demonstrated metal tolerance in S. enterica serovar Typhimurium, and silver ion showed the highest toxicity among the tested metal ions...

  10. Tetracycline accelerates the temporally-regulated invasion response in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Multidrug-resistant (MDR) Salmonella is associated with increased morbidity compared to antibiotic-sensitive strains and is an important health and safety concern in both humans and animals. Salmonella enterica serovar Typhimurium is a prevalent cause of foodborne disease, and a consider...

  11. Motility revertants of opgGH mutants of Salmonella enterica serovar Typhimurium remain defective in mice virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently demonstrated that osmoregulated periplasmic glucans (OPGs) of Salmonella enterica serovar Typhimurium are required for optimal mouse virulence (Bhagwat et al., 2009. Microbiology 155:229-237). However, lack of OPGs also generated pleiotropic phenotypes such as reduced motility and slower...

  12. Correlating Blood Immune Parameters and a CCT7 Genetic Variant with the Shedding of Salmonella enterica Serovar Typhimurium in Swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the current study, 40 crossbred pigs were intranasally inoculated with Salmonella enterica serovar Typhimurium and monitored for Salmonella fecal shedding and blood immune parameters at 2, 7, 14 and 20 days post-inoculation (dpi). Using a multivariate permutation test, a positive correlation was...

  13. Type I interferon induces necroptosis in macrophages during infection with Salmonella enterica serovar Typhimurium

    PubMed Central

    Robinson, Nirmal; McComb, Scott; Mulligan, Rebecca; Dudani, Renu; Krishnan, Lakshmi; Sad, Subash

    2014-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a virulent pathogen that induces rapid host death. Here we observed that host survival after infection with S. Typhimurium was enhanced in the absence of type I interferon signaling, with improved survival of mice deficient in the receptor for type I interferons (Ifnar1−/− mice) that was attributed to macrophages. Although there was no impairment in cytokine expression or inflammasome activation in Ifnar1−/− macrophages, they were highly resistant to S. Typhimurium–induced cell death. Specific inhibition of the kinase RIP1or knockdown of the gene encoding the kinase RIP3 prevented the death of wild-type macrophages, which indicated that necroptosis was a mechanism of cell death. Finally, RIP3-deficient macrophages, which cannot undergo necroptosis, had similarly less death and enhanced control of S. Typhimurium in vivo. Thus, we propose that S. Typhimurium induces the production of type I interferon, which drives necroptosis of macrophages and allows them to evade the immune response. PMID:22922364

  14. Interleukin-17A is required to suppress invasion of Salmonella enterica serovar Typhimurium to enteric mucosa

    PubMed Central

    Mayuzumi, Hirokazu; Inagaki-Ohara, Kyoko; Uyttenhove, Catherine; Okamoto, Yuko; Matsuzaki, Goro

    2010-01-01

    Salmonella enterica serovar Typhimurium (S. typhimurium) causes a localized enteric infection and its elimination is dependent on a T helper type 1 immune response. However, the mechanism of the protective immune response against the pathogen in gut-associated lymphoid tissue (GALT) at an early stage of the infection is not yet clarified. Here, we show that interleukin-17A (IL-17A) was constitutively expressed in GALT; it was also detected on crypt and epithelial cells of the small intestine. Neutralization of the IL-17A in the intestinal lumen exacerbated epithelial damage induced by intestinal S. typhimurium infection at an early stage of the infection. The result suggests that IL-17A has a pivotal role in the immediate early stage of protection against bacterial infection at the intestinal mucosa. As IL-17A neutralization also suppressed the constitutive localization of β-defensin 3 (BD3), an IL-17A-induced antimicrobial peptide, at the apical site of the intestinal mucosa, it is estimated that IL-17A constitutively induces the expression of the antimicrobial peptide to kill invading pathogens at the epithelial surface immediately after the infection. In contrast, interferon-γ is induced around 3 days after S. typhimurium infection, and its expression level increases thereafter. Taken together, the findings lead to the hypothesis that IL-17A participates in the immediate early stage of protection against S. typhimurium intestinal infection whereas interferon-γ is important at a later stage of the infection. PMID:20575990

  15. Multiple roles of putrescine and spermidine in stress resistance and virulence of Salmonella enterica serovar Typhimurium.

    PubMed

    Espinel, Irene Cartas; Guerra, Priscila Regina; Jelsbak, Lotte

    2016-06-01

    Polyamines (putrescine and spermidine) are small-cationic amines ubiquitous in nature and present in most living cells. In recent years they have been linked to virulence of several human pathogens including Shigella spp and Salmonella enterica serovar Typhimurium (S. Typhimurium). Central to S. Typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. In the present study, we have investigated the role of polyamines in intracellular survival and systemic infections of mice. Using a S. Typhimurium mutant defective for putrescine and spermidine biosynthesis, we show that polyamines are essential for coping with reactive nitrogen species, possibly linking polyamines to increased intracellular stress resistance. However, using a mouse model defective for nitric oxide production, we find that polyamines are required for systemic infections independently of host-produced reactive nitrogen species. To distinguish between the physiological roles of putrescine and spermidine, we constructed a strain deficient for spermidine biosynthesis and uptake, but with retained ability to produce and import putrescine. Interestingly, in this mutant we observe a strong attenuation of virulence during infection of mice proficient and deficient for nitric oxide production suggesting that spermidine, specifically, is essential for virulence of S. Typhimurium. PMID:27041598

  16. Salmonella enterica Serovar Typhimurium Exploits Inflammation to Modify Swine Intestinal Microbiota

    PubMed Central

    Drumo, Rosanna; Pesciaroli, Michele; Ruggeri, Jessica; Tarantino, Michela; Chirullo, Barbara; Pistoia, Claudia; Petrucci, Paola; Martinelli, Nicola; Moscati, Livia; Manuali, Elisabetta; Pavone, Silvia; Picciolini, Matteo; Ammendola, Serena; Gabai, Gianfranco; Battistoni, Andrea; Pezzotti, Giovanni; Alborali, Giovanni L.; Napolioni, Valerio; Pasquali, Paolo; Magistrali, Chiara F.

    2016-01-01

    Salmonella enterica serovar Typhimurium is an important zoonotic gastrointestinal pathogen responsible for foodborne disease worldwide. It is a successful enteric pathogen because it has developed virulence strategies allowing it to survive in a highly inflamed intestinal environment exploiting inflammation to overcome colonization resistance provided by intestinal microbiota. In this study, we used piglets featuring an intact microbiota, which naturally develop gastroenteritis, as model for salmonellosis. We compared the effects on the intestinal microbiota induced by a wild type and an attenuated S. Typhimurium in order to evaluate whether the modifications are correlated with the virulence of the strain. This study showed that Salmonella alters microbiota in a virulence-dependent manner. We found that the wild type S. Typhimurium induced inflammation and a reduction of specific protecting microbiota species (SCFA-producing bacteria) normally involved in providing a barrier against pathogens. Both these effects could contribute to impair colonization resistance, increasing the host susceptibility to wild type S. Typhimurium colonization. In contrast, the attenuated S. Typhimurium, which is characterized by a reduced ability to colonize the intestine, and by a very mild inflammatory response, was unable to successfully sustain competition with the microbiota. PMID:26835435

  17. Yersinia enterocolitica inhibits Salmonella enterica serovar Typhimurium and Listeria monocytogenes cellular uptake.

    PubMed

    Habyarimana, Fabien; Swearingen, Matthew C; Young, Glenn M; Seveau, Stephanie; Ahmer, Brian M M

    2014-01-01

    Yersinia enterocolitica biovar 1B employs two type three secretion systems (T3SS), Ysa and Ysc, which inject effector proteins into macrophages to prevent phagocytosis. Conversely, Salmonella enterica serovar Typhimurium uses a T3SS encoded by Salmonella pathogenicity island 1 (SPI1) to actively invade cells that are normally nonphagocytic and a second T3SS encoded by SPI2 to survive within macrophages. Given the distinctly different outcomes that occur with regard to host cell uptake of S. Typhimurium and Y. enterocolitica, we investigated how each pathogen influences the internalization outcome of the other. Y. enterocolitica reduces S. Typhimurium invasion of HeLa and Caco-2 cells to a level similar to that observed using an S. Typhimurium SPI1 mutant alone. However, Y. enterocolitica had no effect on S. Typhimurium uptake by J774.1 or RAW264.7 macrophage-like cells. Y. enterocolitica was also able to inhibit the invasion of epithelial and macrophage-like cells by Listeria monocytogenes. Y. enterocolitica mutants lacking either the Ysa or Ysc T3SS were partially defective, while double mutants were completely defective, in blocking S. Typhimurium uptake by epithelial cells. S. Typhimurium encodes a LuxR homolog, SdiA, which detects N-acylhomoserine lactones (AHLs) produced by Y. enterocolitica and upregulates the expression of an invasin (Rck) and a putative T3SS effector (SrgE). Two different methods of constitutively activating the S. Typhimurium SdiA regulon failed to reverse the uptake blockade imposed by Y. enterocolitica. PMID:24126528

  18. Yersinia enterocolitica Inhibits Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Cellular Uptake

    PubMed Central

    Habyarimana, Fabien; Swearingen, Matthew C.; Young, Glenn M.; Seveau, Stephanie

    2014-01-01

    Yersinia enterocolitica biovar 1B employs two type three secretion systems (T3SS), Ysa and Ysc, which inject effector proteins into macrophages to prevent phagocytosis. Conversely, Salmonella enterica serovar Typhimurium uses a T3SS encoded by Salmonella pathogenicity island 1 (SPI1) to actively invade cells that are normally nonphagocytic and a second T3SS encoded by SPI2 to survive within macrophages. Given the distinctly different outcomes that occur with regard to host cell uptake of S. Typhimurium and Y. enterocolitica, we investigated how each pathogen influences the internalization outcome of the other. Y. enterocolitica reduces S. Typhimurium invasion of HeLa and Caco-2 cells to a level similar to that observed using an S. Typhimurium SPI1 mutant alone. However, Y. enterocolitica had no effect on S. Typhimurium uptake by J774.1 or RAW264.7 macrophage-like cells. Y. enterocolitica was also able to inhibit the invasion of epithelial and macrophage-like cells by Listeria monocytogenes. Y. enterocolitica mutants lacking either the Ysa or Ysc T3SS were partially defective, while double mutants were completely defective, in blocking S. Typhimurium uptake by epithelial cells. S. Typhimurium encodes a LuxR homolog, SdiA, which detects N-acylhomoserine lactones (AHLs) produced by Y. enterocolitica and upregulates the expression of an invasin (Rck) and a putative T3SS effector (SrgE). Two different methods of constitutively activating the S. Typhimurium SdiA regulon failed to reverse the uptake blockade imposed by Y. enterocolitica. PMID:24126528

  19. Protein Acetylation Is Involved in Salmonella enterica Serovar Typhimurium Virulence.

    PubMed

    Sang, Yu; Ren, Jie; Ni, Jinjing; Tao, Jing; Lu, Jie; Yao, Yu-Feng

    2016-06-01

    Salmonella causes a range of diseases in different hosts, including enterocolitis and systemic infection. Lysine acetylation regulates many eukaryotic cellular processes, but its function in bacteria is largely unexplored. The acetyltransferase Pat and NAD(+)-dependent deacetylase CobB are involved in the reversible protein acetylation in Salmonella Typhimurium. Here, we used cell and animal models to evaluate the virulence of pat and cobB deletion mutants in S. Typhimurium and found that pat is critical for bacterial intestinal colonization and systemic infection. Next, to understand the underlying mechanism, genome-wide transcriptome was analyzed. RNA sequencing data showed that the expression of Salmonella pathogenicity island 1 (SPI-1) is partially dependent on pat In addition, we found that HilD, a key transcriptional regulator of SPI-1, is a substrate of Pat. The acetylation of HilD by Pat maintained HilD stability and was essential for the transcriptional activation of HilA. Taken together, these results suggest that a protein acetylation system regulates SPI-1 expression by controlling HilD in a posttranslational manner to mediate S. Typhimurium virulence. PMID:26810370

  20. Effect of Protein SV-IV on Experimental Salmonella enterica Serovar Typhimurium Infection in Mice

    PubMed Central

    Romano-Carratelli, Caterina; Bentivoglio, Concetta; Nuzzo, Immacolata; Benedetto, Nunzia; Buommino, Elisabetta; Cozzolino, Anna; Cartenì, Maria; Morelli, Francesco; Costanza, Maria Rosaria; Metafora, Biancamaria; Metafora, Vittoria; Metafora, Salvatore

    2002-01-01

    Seminal vesicle protein IV (SV-IV) is a secretory anti-inflammatory, procoagulant, and immunomodulatory protein produced in large amounts by the seminal vesicle epithelium of the rat under the strict transcriptional control of androgen. In particular, this protein was shown to possess the ability to markedly inhibit in vivo the humoral and cell-mediated immune responses of mice to nonbacterial cellular antigens (sheep erythrocytes and spermatozoa). We report data that demonstrate that in mice treated with SV-IV and infected with Salmonella enterica serovar Typhimurium, SV-IV is able to downregulate some important immunological and biochemical parameters that serovar Typhimurium normally upregulates in these animals. This event did not correlate with a lower bacterial burden but was associated with a markedly increased one (300%). Furthermore, the treatment of mice with SV-IV alone also produced a significant increase in the rate of mortality among serovar Typhimurium-infected animals. The mechanism underlying these phenomena was investigated, and the strong immunosuppression produced by SV-IV in serovar Typhimurium-infected mice was suggested to be the basis for the increased rate of mortality. The SV-IV-mediated immunosuppression was characterized by a decrease in the humoral and cell-mediated immune responses, altered lymphocyte-macrophage interaction, downregulation of cytokine and inducible nitric oxide synthase gene expression, inhibition of macrophage phagocytosis and intracellular killing activities, and absence of apoptosis in the splenocyte population of SV-IV- and serovar Typhimurium-treated mice. The immunosuppressive activity of SV-IV was specific and was not due to aspecific cytotoxic effects. SV-IV-specific receptors (Kd = 10−8 M) occurring on the macrophage and lymphocyte plasma membranes may be involved in the molecular mechanism underlying the SV-IV-mediated immunosuppression. Some results obtained by the 3-(4,5-dimethylthiazol-2-yl)-2

  1. Chloramphenicol and tetracycline decrease motility and increase invasion and attachment gene expression in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most common serovars isolated from humans and livestock, and over 35 percent of these isolates are resistant to three or more antibiotics. Multidrug-resistant (MDR) Salmonella is a public health concern as it is associated with i...

  2. Design of Glycoconjugate Vaccines against Invasive African Salmonella enterica Serovar Typhimurium

    PubMed Central

    Micoli, F.; Lanzilao, L.; Gavini, M.; Alfini, R.; Brandt, C.; Clare, S.; Mastroeni, P.; Saul, A.; MacLennan, C. A.

    2014-01-01

    Nontyphoidal salmonellae, particularly Salmonella enterica serovar Typhimurium, are a major cause of invasive disease in Africa, affecting mainly young children and HIV-infected individuals. Glycoconjugate vaccines provide a safe and reliable strategy against invasive polysaccharide-encapsulated pathogens, and lipopolysaccharide (LPS) is a target of protective immune responses. With the aim of designing an effective vaccine against S. Typhimurium, we have synthesized different glycoconjugates, by linking O-antigen and core sugars (OAg) of LPS to the nontoxic mutant of diphtheria toxin (CRM197). The OAg-CRM197 conjugates varied in (i) OAg source, with three S. Typhimurium strains used for OAg extraction, producing OAg with differences in structural specificities, (ii) OAg chain length, and (iii) OAg/CRM197 ratio. All glycoconjugates were compared for immunogenicity and ability to induce serum bactericidal activity in mice. In vivo enhancement of bacterial clearance was assessed for a selected S. Typhimurium glycoconjugate by challenge with live Salmonella. We found that the largest anti-OAg antibody responses were elicited by (i) vaccines synthesized from OAg with the highest glucosylation levels, (ii) OAg composed of mixed- or medium-molecular-weight populations, and (iii) a lower OAg/CRM197 ratio. In addition, we found that bactericidal activity can be influenced by S. Typhimurium OAg strain, most likely as a result of differences in OAg O-acetylation and glucosylation. Finally, we confirmed that mice immunized with the selected OAg-conjugate were protected against S. Typhimurium colonization of the spleen and liver. In conclusion, our findings indicate that differences in the design of OAg-based glycoconjugate vaccines against invasive African S. Typhimurium can have profound effects on immunogenicity and therefore optimal vaccine design requires careful consideration. PMID:25547792

  3. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104.

    PubMed

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Ussery, David W; Lund, Ole; Crook, Derrick W; Wilson, Daniel J; Aarestrup, Frank M

    2016-04-01

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella entericaserovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315S Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonellafrom pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections. PMID:26944846

  4. Direct ROS scavenging activity of CueP from Salmonella enterica serovar Typhimurium.

    PubMed

    Yoon, Bo-Young; Yeom, Ji-Hyun; Kim, Jin-Sik; Um, Si-Hyeon; Jo, Inseong; Lee, Kangseok; Kim, Yong-Hak; Ha, Nam-Chul

    2014-02-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu, Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages. PMID:24598994

  5. Salmonella enterica Serovar Typhimurium Invades Fibroblasts by Multiple Routes Differing from the Entry into Epithelial Cells▿

    PubMed Central

    Aiastui, Ana; Pucciarelli, M. Graciela; García-del Portillo, Francisco

    2010-01-01

    Fibroblasts are ubiquitous cells essential to tissue homeostasis. Despite their nonphagocytic nature, fibroblasts restrain replication of intracellular bacterial pathogens such as Salmonella enterica serovar Typhimurium. The extent to which the entry route of the pathogen determines this intracellular response is unknown. Here, we analyzed S. Typhimurium invasion in fibroblasts obtained from diverse origins, including primary cultures and stable nontransformed cell lines derived from normal tissues. Features distinct to the invasion of epithelial cells were found in all fibroblasts tested. In some fibroblasts, bacteria lacking the type III secretion system encoded in the Salmonella pathogenicity island 1 displayed significant invasion rates and induced the formation of lamellipodia and filopodia at the fibroblast-bacteria contact site. Other bacterial invasion traits observed in fibroblasts were the requirement of phosphatidylinositol 3-kinase, mitogen-activated protein kinase MEK1, and both actin filaments and microtubules. RNA interference studies showed that different Rho family GTPases are targeted by S. Typhimurium to enter into distinct fibroblasts. Rac1 and Cdc42 knockdown affected invasion of normal rat kidney fibroblasts, whereas none of the GTPases tested (Rac1, Cdc42, RhoA, or RhoG) was essential for invasion of immortalized human foreskin fibroblasts. Collectively, these data reveal a marked diversity in the modes used by S. Typhimurium to enter into fibroblasts. PMID:20368348

  6. Expression divergence between Escherichia coli and Salmonella enterica serovar Typhimurium reflects their lifestyles.

    PubMed

    Meysman, Pieter; Sánchez-Rodríguez, Aminael; Fu, Qiang; Marchal, Kathleen; Engelen, Kristof

    2013-06-01

    Escherichia coli K12 is a commensal bacteria and one of the best-studied model organisms. Salmonella enterica serovar Typhimurium, on the other hand, is a facultative intracellular pathogen. These two prokaryotic species can be considered related phylogenetically, and they share a large amount of their genetic material, which is commonly termed the "core genome." Despite their shared core genome, both species display very different lifestyles, and it is unclear to what extent the core genome, apart from the species-specific genes, plays a role in this lifestyle divergence. In this study, we focus on the differences in expression domains for the orthologous genes in E. coli and S. Typhimurium. The iterative comparison of coexpression methodology was used on large expression compendia of both species to uncover the conservation and divergence of gene expression. We found that gene expression conservation occurs mostly independently from amino acid similarity. According to our estimates, at least more than one quarter of the orthologous genes has a different expression domain in E. coli than in S. Typhimurium. Genes involved with key cellular processes are most likely to have conserved their expression domains, whereas genes showing diverged expression are associated with metabolic processes that, although present in both species, are regulated differently. The expression domains of the shared "core" genome of E. coli and S. Typhimurium, consisting of highly conserved orthologs, have been tuned to help accommodate the differences in lifestyle and the pathogenic potential of Salmonella. PMID:23427276

  7. Multilocus Sequence Typing Lacks the Discriminatory Ability of Pulsed-Field Gel Electrophoresis for Typing Salmonella enterica Serovar Typhimurium

    PubMed Central

    Fakhr, Mohamed K.; Nolan, Lisa K.; Logue, Catherine M.

    2005-01-01

    Nontyphoidal salmonellae are among the leading causes of food-borne disease in the United States. Because of the importance of Salmonella enterica in food-borne disease, numerous typing methodologies have been developed. Among the several molecular typing methods, pulsed-field gel electrophoresis (PFGE) is currently considered the “gold standard” technique in typing Salmonella. The aim of this study was to compare the discriminatory power of PFGE to multilocus sequence typing (MLST) in typing Salmonella enterica serovar Typhimurium clinical isolates. A total of 85 Salmonella Typhimurium clinical isolates from cattle were used in this study. PFGE using XbaI was performed on the 85 isolates by the Centers for Disease Control and Prevention method, and data were analyzed using the BioNumerics software package. Fifty PFGE profiles were observed among the isolates, and these grouped into three major clusters. For the MLST analysis, the manB, pduF, glnA, and spaM genes were amplified by PCR from the same 85 isolates. DNA sequencing of these four genes, manB, pduF, glnA, and spaM, showed no genetic diversity among the isolates tested, with a 100% identity in nucleotide sequence. Moreover, the DNA sequences of the aforementioned genes showed 100% identity to the sequence reported in GenBank for the S. enterica serovar Typhimurium LT2 strain. Therefore, MLST, using these genes, lacks the discriminatory power of PFGE for typing Salmonella enterica serovar Typhimurium. PMID:15872244

  8. Multilocus sequence typing lacks the discriminatory ability of pulsed-field gel electrophoresis for typing Salmonella enterica serovar Typhimurium.

    PubMed

    Fakhr, Mohamed K; Nolan, Lisa K; Logue, Catherine M

    2005-05-01

    Nontyphoidal salmonellae are among the leading causes of food-borne disease in the United States. Because of the importance of Salmonella enterica in food-borne disease, numerous typing methodologies have been developed. Among the several molecular typing methods, pulsed-field gel electrophoresis (PFGE) is currently considered the "gold standard" technique in typing Salmonella. The aim of this study was to compare the discriminatory power of PFGE to multilocus sequence typing (MLST) in typing Salmonella enterica serovar Typhimurium clinical isolates. A total of 85 Salmonella Typhimurium clinical isolates from cattle were used in this study. PFGE using XbaI was performed on the 85 isolates by the Centers for Disease Control and Prevention method, and data were analyzed using the BioNumerics software package. Fifty PFGE profiles were observed among the isolates, and these grouped into three major clusters. For the MLST analysis, the manB, pduF, glnA, and spaM genes were amplified by PCR from the same 85 isolates. DNA sequencing of these four genes, manB, pduF, glnA, and spaM, showed no genetic diversity among the isolates tested, with a 100% identity in nucleotide sequence. Moreover, the DNA sequences of the aforementioned genes showed 100% identity to the sequence reported in GenBank for the S. enterica serovar Typhimurium LT2 strain. Therefore, MLST, using these genes, lacks the discriminatory power of PFGE for typing Salmonella enterica serovar Typhimurium. PMID:15872244

  9. An rfaH mutant of Salmonella enterica serovar typhimurium is attenuated in swine and reduces intestinal colonization, fecal shedding, and disease severity due to virulent Salmonella Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine are often asymptomatic carriers of Salmonella spp., and interventions are needed to limit colonization of swine to enhance food safety and reduce environmental contamination. We evaluated the attenuation and potential vaccine use in pigs of a Salmonella enterica serovar Typhimurium mutant of r...

  10. Serological response of swine to an attenuated Salmonella enterica serovar Typhimurium strain that reduces gastrointestinal colonization, fecal shedding and disease due to virulent Salmonella Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine are often asymptomatic carriers of Salmonella spp. Interventions are needed to limit Salmonella colonization of swine to enhance food safety. An attenuated Salmonella enterica serovar Typhimurium mutant strain (BBS 202) was tested in swine to determine whether vaccination could provide protect...

  11. Characterization of Small ColE1-Like Plasmids Conferring Kanamycin Resistance in Salmonella enterica subsp. enterica serovars Typhimurium and Newport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multi-antibiotic resistant (MR) Salmonella enterica serovars Typhimurium and Newport are an increasing concern in human and animal health. Many strains are known to carry antibiotic resistance determinants on multiple plasmids, yet detailed information is scarce. Three plasmids conferring kanamycin...

  12. Genetics of Swarming Motility in Salmonella enterica Serovar Typhimurium: Critical Role for Lipopolysaccharide

    PubMed Central

    Toguchi, Adam; Siano, Michael; Burkart, Mark; Harshey, Rasika M.

    2000-01-01

    Salmonella enterica serovar Typhimurium can differentiate into hyperflagellated swarmer cells on agar of an appropriate consistency (0.5 to 0.8%), allowing efficient colonization of the growth surface. Flagella are essential for this form of motility. In order to identify genes involved in swarming, we carried out extensive transposon mutagenesis of serovar Typhimurium, screening for those that had functional flagella yet were unable to swarm. A majority of these mutants were defective in lipopolysaccharide (LPS) synthesis, a large number were defective in chemotaxis, and some had defects in putative two-component signaling components. While the latter two classes were defective in swarmer cell differentiation, representative LPS mutants were not and could be rescued for swarming by external addition of a biosurfactant. A mutation in waaG (LPS core modification) secreted copious amounts of slime and showed a precocious swarming phenotype. We suggest that the O antigen improves surface “wettability” required for swarm colony expansion, that the LPS core could play a role in slime generation, and that multiple two-component systems cooperate to promote swarmer cell differentiation. The failure to identify specific swarming signals such as amino acids, pH changes, oxygen, iron starvation, increased viscosity, flagellar rotation, or autoinducers leads us to consider a model in which the external slime is itself both the signal and the milieu for swarming motility. The model explains the cell density dependence of the swarming phenomenon. PMID:11053374

  13. Microgravity as a novel environmental signal affecting Salmonella enterica serovar Typhimurium virulence

    NASA Technical Reports Server (NTRS)

    Nickerson, C. A.; Ott, C. M.; Mister, S. J.; Morrow, B. J.; Burns-Keliher, L.; Pierson, D. L.

    2000-01-01

    The effects of spaceflight on the infectious disease process have only been studied at the level of the host immune response and indicate a blunting of the immune mechanism in humans and animals. Accordingly, it is necessary to assess potential changes in microbial virulence associated with spaceflight which may impact the probability of in-flight infectious disease. In this study, we investigated the effect of altered gravitational vectors on Salmonella virulence in mice. Salmonella enterica serovar Typhimurium grown under modeled microgravity (MMG) were more virulent and were recovered in higher numbers from the murine spleen and liver following oral infection compared to organisms grown under normal gravity. Furthermore, MMG-grown salmonellae were more resistant to acid stress and macrophage killing and exhibited significant differences in protein synthesis than did normal-gravity-grown cells. Our results indicate that the environment created by simulated microgravity represents a novel environmental regulatory factor of Salmonella virulence.

  14. Antagonistic activity of Lactobacillus acidophilus LB against intracellular Salmonella enterica serovar Typhimurium infecting human enterocyte-like Caco-2/TC-7 cells.

    PubMed

    Coconnier, M H; Liévin, V; Lorrot, M; Servin, A L

    2000-03-01

    To gain further insight into the mechanism by which lactobacilli develop antimicrobial activity, we have examined how Lactobacillus acidophilus LB inhibits the promoted cellular injuries and intracellular lifestyle of Salmonella enterica serovar Typhimurium SL1344 infecting the cultured, fully differentiated human intestinal cell line Caco-2/TC-7. We showed that the spent culture supernatant of strain LB (LB-SCS) decreases the number of apical serovar Typhimurium-induced F-actin rearrangements in infected cells. LB-SCS treatment efficiently decreased transcellular passage of S. enterica serovar Typhimurium. Moreover, LB-SCS treatment inhibited intracellular growth of serovar Typhimurium, since treated intracellular bacteria displayed a small, rounded morphology resembling that of resting bacteria. We also showed that LB-SCS treatment inhibits adhesion-dependent serovar Typhimurium-induced interleukin-8 production. PMID:10698785

  15. Novel Salmonella enterica serovar Typhimurium protein that is indispensable for virulence and intracellular replication.

    PubMed

    van der Straaten, T; van Diepen, A; Kwappenberg, K; van Voorden, S; Franken, K; Janssen, R; Kusters, J G; Granger, D L; van Dissel, J T

    2001-12-01

    Upon contact with host cells, the intracellular pathogen Salmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches. In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. This study reports the phenotypic and genotypic characterization of an S. enterica serovar Typhimurium mutant that is hypersusceptible to superoxide. The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribed Salmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonella chromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 10(4) to 10(7) bacteria in C3H/HeN and 10(1) to 10(4) bacteria in BALB/c mice, the mutant strain was less virulent than the wild type. Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms. Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so. This phenotype could be restored to that of the wild type by sspJ complementation. The SspJ protein is found in the cytoplasmic membrane and periplasmic space. Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function. We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity. PMID:11705915

  16. Cellular Requirements for Systemic Control of Salmonella enterica Serovar Typhimurium Infections in Mice

    PubMed Central

    Bedoui, Sammy

    2014-01-01

    The rational design of vaccines requires an understanding of the contributions of individual immune cell subsets to immunity. With this understanding, targeted vaccine delivery approaches and adjuvants can be developed to maximize vaccine efficiency and to minimize side effects (S. H. E. Kaufmann et al., Immunity 33:555–577, 2010; T. Ben-Yedidia and R. Arnon, Hum. Vaccines 1:95–101, 2005). We have addressed the contributions of different immune cell subsets and their ability to contribute to the control and clearance of the facultative intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) in a murine model. Using a systematic and reproducible model of experimental attenuated S. Typhimurium infection, we show that distinct lymphocyte deficiencies lead to one of four different infection outcomes: clearance, chronic infection, early death, or late death. Our study demonstrates a high level of functional redundancy in the ability of different lymphocyte subsets to provide interferon gamma (IFN-γ), a critical cytokine in Salmonella immunity. Whereas early control of the infection was entirely dependent on IFN-γ but not on any particular lymphocyte subset, clearance of the infection critically required CD4+ T cells but appeared to be independent of IFN-γ. These data reinforce the idea of a bimodal immune response against Salmonella: an early T cell-independent but IFN-γ-dependent phase and a late T cell-dependent phase that may be IFN-γ independent. PMID:25225248

  17. Biofilm formation ability of Salmonella enterica serovar Typhimurium acrAB mutants.

    PubMed

    Schlisselberg, Dov B; Kler, Edna; Kisluk, Guy; Shachar, Dina; Yaron, Sima

    2015-10-01

    Recent studies offer contradictory findings about the role of multidrug efflux pumps in bacterial biofilm development. Thus, the aim of this study was to investigate the involvement of the AcrAB efflux pump in biofilm formation by investigating the ability of AcrB and AcrAB null mutants of Salmonella enterica serovar Typhimurium to produce biofilms. Three models were used to compare the ability of S. Typhimurium wild-type and its mutants to form biofilms: formation of biofilm on polystyrene surfaces; production of biofilm (mat model) on the air/liquid interface; and expression of curli and cellulose on Congo red-supplemented agar plates. All three investigated genotypes formed biofilms with similar characteristics. However, upon exposure to chloramphenicol, formation of biofilms on solid surfaces as well as the production of curli were either reduced or were delayed more significantly in both mutants, whilst there was no visible effect on pellicle formation. It can be concluded that when no selective pressure is applied, S. Typhimurium is able to produce biofilms even when the AcrAB efflux pumps are inactivated, implying that the use of efflux pump inhibitors to prevent biofilm formation is not a general solution and that combined treatments might be more efficient. Other factors that affect the ability to produce biofilms depending on efflux pump activity are yet to be identified. PMID:26260191

  18. Spatial Segregation of Virulence Gene Expression during Acute Enteric Infection with Salmonella enterica serovar Typhimurium

    PubMed Central

    Laughlin, Richard C.; Knodler, Leigh A.; Barhoumi, Roula; Payne, H. Ross; Wu, Jing; Gomez, Gabriel; Pugh, Roberta; Lawhon, Sara D.; Bäumler, Andreas J.; Steele-Mortimer, Olivia; Adams, L. Garry

    2014-01-01

    ABSTRACT To establish a replicative niche during its infectious cycle between the intestinal lumen and tissue, the enteric pathogen Salmonella enterica serovar Typhimurium requires numerous virulence genes, including genes for two type III secretion systems (T3SS) and their cognate effectors. To better understand the host-pathogen relationship, including early infection dynamics and induction kinetics of the bacterial virulence program in the context of a natural host, we monitored the subcellular localization and temporal expression of T3SS-1 and T3SS-2 using fluorescent single-cell reporters in a bovine, ligated ileal loop model of infection. We observed that the majority of bacteria at 2 h postinfection are flagellated, express T3SS-1 but not T3SS-2, and are associated with the epithelium or with extruding enterocytes. In epithelial cells, S. Typhimurium cells were surrounded by intact vacuolar membranes or present within membrane-compromised vacuoles that typically contained numerous vesicular structures. By 8 h postinfection, T3SS-2-expressing bacteria were detected in the lamina propria and in the underlying mucosa, while T3SS-1-expressing bacteria were in the lumen. Our work identifies for the first time the temporal and spatial regulation of T3SS-1 and -2 expression during an enteric infection in a natural host and provides further support for the concept of cytosolic S. Typhimurium in extruding epithelium as a mechanism for reseeding the lumen. PMID:24496791

  19. Emergence of clinical Salmonella enterica serovar Typhimurium isolates with concurrent resistance to ciprofloxacin, ceftriaxone, and azithromycin.

    PubMed

    Wong, Marcus Ho Yin; Yan, Meiying; Chan, Edward Wai Chi; Biao, Kan; Chen, Sheng

    2014-07-01

    Salmonella infection is an important public health issue for which the needs of antimicrobial treatment are increasing. A total of 546 human clinical S. enterica serovar Typhimurium isolates were recovered from patients in hospitals in China during the period of 2005 to ∼ 2011. Twenty percent of the isolates exhibited resistance to ciprofloxacin, and 4% were resistant to ceftriaxone. Importantly, for the first time, 12 (2%) S. Typhimurium isolates resistant to both ciprofloxacin and ceftriaxone were recovered; among these 12 isolates, two were also resistant to azithromycin, and one was resistant to all other drugs tested. The combined effects of various transferrable extended-spectrum β-lactamase determinants and a novel efflux-based ciprofloxacin resistance mechanism encoded by the mobile efflux gene oqxAB were responsible for the emergence of these extremely (highly) drug-resistant (XDR) S. Typhimurium isolates. The dissemination of resistance genes, such as those encoding ESBLs and the OqxAB pump, among Salmonella organisms will speed up the selection of XDR Salmonella, posing a huge threat to public health and Salmonella infection control. PMID:24752251

  20. Cellular requirements for systemic control of Salmonella enterica serovar Typhimurium infections in mice.

    PubMed

    Kupz, Andreas; Bedoui, Sammy; Strugnell, Richard A

    2014-12-01

    The rational design of vaccines requires an understanding of the contributions of individual immune cell subsets to immunity. With this understanding, targeted vaccine delivery approaches and adjuvants can be developed to maximize vaccine efficiency and to minimize side effects (S. H. E. Kaufmann et al., Immunity 33:555-577, 2010; T. Ben-Yedidia and R. Arnon, Hum. Vaccines 1:95-101, 2005). We have addressed the contributions of different immune cell subsets and their ability to contribute to the control and clearance of the facultative intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) in a murine model. Using a systematic and reproducible model of experimental attenuated S. Typhimurium infection, we show that distinct lymphocyte deficiencies lead to one of four different infection outcomes: clearance, chronic infection, early death, or late death. Our study demonstrates a high level of functional redundancy in the ability of different lymphocyte subsets to provide interferon gamma (IFN-γ), a critical cytokine in Salmonella immunity. Whereas early control of the infection was entirely dependent on IFN-γ but not on any particular lymphocyte subset, clearance of the infection critically required CD4(+) T cells but appeared to be independent of IFN-γ. These data reinforce the idea of a bimodal immune response against Salmonella: an early T cell-independent but IFN-γ-dependent phase and a late T cell-dependent phase that may be IFN-γ independent. PMID:25225248

  1. Bistable Expression of CsgD in Salmonella enterica Serovar Typhimurium Connects Virulence to Persistence

    PubMed Central

    MacKenzie, Keith D.; Wang, Yejun; Shivak, Dylan J.; Wong, Cynthia S.; Hoffman, Leia J. L.; Lam, Shirley; Kröger, Carsten; Cameron, Andrew D. S.; Townsend, Hugh G. G.; Köster, Wolfgang

    2015-01-01

    Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogen Salmonella enterica serovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist when S. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allows S. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment. PMID:25824832

  2. Natural surface coating to inactivate Salmonella enterica serovar Typhimurium and maintain quality of cherry tomatoes.

    PubMed

    Yun, Juan; Fan, Xuetong; Li, Xihong; Jin, Tony Z; Jia, Xiaoyu; Mattheis, James P

    2015-01-16

    The objective of the present study was to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three attenuated strains on the smooth skin surface and stem scar area. The zein-based coatings with and without cinnamon (up to 20%) and mustard essential oil or a commercial wax formulation were applied onto tomatoes and the treated fruits were stored at 10 °C for up to 3 weeks. Populations of S. Typhimurium decreased with increased essential oil concentration and storage duration. S. Typhimurium populations on the smooth skin surface were reduced by 4.6 and 2.8 log colony forming units(CFU)/g by the zein coatings with 20% cinnamon and 20% mustard oil, respectively, 5h after coating. The same coating reduced populations of S. Typhimurium to levels below detection limit (1.0 log CFU/g) on the stem scar area of tomato during 7 days of storage at 10 °C. Salmonella populations were not reduced on fruit coated with the commercial wax. All of the coatings resulted in reduced weight loss compared with uncoated control. Compared with the control, loss of firmness and ascorbic acid during storage was prevented by all of the coatings except the zein coating with 20% mustard oil which enhanced softening. Color was not consistently affected by any of the coating treatments during 21 days of storage at 10°C. The results suggest that the zein-based coating containing cinnamon oil might be used to enhance microbial safety and quality of tomato. PMID:25462924

  3. Differential innate immune responses of bovine peripheral blood leukocytes to Salmonella enterica serovars Dublin, Typhimurium, and Enteritidis.

    PubMed

    Pan, Deng; Rostagno, Marcos H; Ebner, Paul D; Eicher, Susan D

    2015-05-15

    The majority of Salmonella serovars cause no clinical disease in cattle, while some are associated with severe disease. The objective of the current study was to determine the innate immune responses of bovine peripheral blood leukocytes exposed to Salmonella enterica serovar Dublin (bovine-specific), Salmonella typhimurium (murine adapted, but zoonotic), and Salmonella enteritidis (poultry host-adapted) in 3-week-old calves. All Salmonella exposures increased cell surface CD14 and CD18 regardless of serovar. The greatest CD14 marker mean fluorescence was in monocytes and the greatest mean fluorescent of the marker mean was in neutrophils. Phagocytosis increased with all serovars, but was not different among them. Neutrophils had the greatest marker mean fluorescence for phagocytosis, with all serovars being equal. Oxidative burst increased in all serovars compared to control cells, but were not different among the serovars. Neutrophils and monocytes were similar in the oxidative burst, with limited oxidative burst detected in the primarily lymphocyte population. mRNA expression of TNF-α, IL-8, and IL-12, increased above the control cells whereas none of these serovars affected mRNA expression of TLR4. TNF-α was greatest in S. enterica and S. typhimurium, compared to Salmonella dublin. In contrast, IL-8 was expressed more in S. dublin than S. typhiurium, with S. Enteriditus intermediary. These results show while cell surface markers, phagocytosis, and oxidative burst were largely unaffected by serovar, cytokine and chemokine expression differed among the Salmonella serovars. It appears that internal responses of the cells differ, rather than cell recognition, creating pathogenicity differences among of the serovars, even in the neonate with developing immunity. PMID:25847354

  4. Ethanolamine Utilization Contributes to Proliferation of Salmonella enterica Serovar Typhimurium in Food and in Nematodes▿

    PubMed Central

    Srikumar, Shabarinath; Fuchs, Thilo M.

    2011-01-01

    Only three pathogenic bacterial species, Salmonella enterica, Clostridium perfringens, and Listeria monocytogenes, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesized de novo only under anaerobic conditions. Although the eut, pdu, and cob-cbi gene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of the Salmonella enterica serovar Typhimurium promoters PeutS, PpocR, PpduF, and PpduA to a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for PeutS and PpduA, which drive the expression of most eut and pdu genes. To correlate these significant expression data with growth properties, nonpolar deletions of pocR, regulating the pdu and cob-cbi genes, and of eutR, involved in eut gene activation, were constructed in S. Typhimurium strain 14028. During exponential growth of the mutants 14028ΔpocR and 14028ΔeutR, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using the Caenorhabditis elegans infection model, we could also demonstrate that the proliferation of S. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression of eut and pdu genes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms. PMID:21037291

  5. Characterization of a Monoclonal Antibody Directed against Salmonella enterica Serovar Typhimurium and Serovar [4,5,12:i:−] ▿

    PubMed Central

    Rementeria, A.; Vivanco, A. B.; Ramirez, A.; Hernando, F. L.; Bikandi, J.; Herrera-León, S.; Echeita, A.; Garaizar, J.

    2009-01-01

    Flagellar extracts of Salmonella enterica serovars expressing phase 2 H1 antigenic complex (H:1,2, H:1,5, H:1,6, and H:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the fljB gene from serovar Typhimurium at codon 218, transforming threonine to alanine, expressed in Escherichia coli (fljB218A) were used to analyze the H1 antigenic complex. Cross-reactions were detected by Western blotting and dot blotting using commercial polyclonal antibodies against the different wild-type extracts and mutant FljB218A. Therefore, we produced a monoclonal antibody (MAb), 23D4, isotyped as immunoglobulin M, against H:1,2 S. enterica serovar Typhimurium flagellin. The mutant flagellin was not recognized by this MAb. When a large number of phase 1 and phase 2 flagellin antigens of different serovars were used to characterize the 23D4 MAb, only extracts of serovars Typhimurium and [4,5,12:i:−] reacted. The protein composition of phase 1 and phase 2 extracts and highly purified H:1,2 flagellin from serovar Typhimurium strain LT2 and extract of strain 286 (serovar [4,5,12:i:−]), which reacted with the MAb, was studied. Phase 2 flagellin (FljBH:1,2) was detected in phase 1 and phase 2 flagellar heat extracts of serovar Typhimurium and was the single protein identified in all spots of purified H:1,2 flagellin. FliC, FlgK, and other proteins were detected in some immunoreactive spots and in the flagellar extract of serovar [4,5,12:i:−]. Immunoelectron microscopy of complete bacteria with 23D4 showed MAb attachment at the base of flagella, although the MAb failed to recognize the filament of flagella. Nevertheless, the results obtained by the other immunological tests (enzyme-linked immunosorbent assay, Western blotting, and dot blotting) indicate a reaction against flagellins. The epitopes could also be shared by other proteins on spots where FljB is not present, such as aminopeptidase B, isocitrate lyase, InvE, EF-TuA, enolase, DnaK, and others. In conclusion

  6. Salmonella enterica Serovar Typhimurium ompS1 and ompS2 Mutants Are Attenuated for Virulence in Mice

    PubMed Central

    Rodríguez-Morales, Olivia; Fernández-Mora, Marcos; Hernández-Lucas, Ismael; Vázquez, Alejandra; Puente, José Luis; Calva, Edmundo

    2006-01-01

    Salmonella enterica serovar Typhimurium mutants with mutations in the ompS1 and ompS2 genes, which code for quiescent porins, were nevertheless highly attenuated for virulence in a mouse model, indicating a role in pathogenesis. Similarly, a strain with a mutation in the gene coding for LeuO, a positive regulator of ompS2, was also attenuated. PMID:16428792

  7. Salmonella Enterica Serovar Typhimurium BipA Exhibits Two Distinct Ribosome Binding Modes

    SciTech Connect

    deLivron, M.; Robinson, V

    2008-01-01

    BipA is a highly conserved prokaryotic GTPase that functions to influence numerous cellular processes in bacteria. In Escherichia coli and Salmonella enterica serovar Typhimurium, BipA has been implicated in controlling bacterial motility, modulating attachment and effacement processes, and upregulating the expression of virulence genes and is also responsible for avoidance of host defense mechanisms. In addition, BipA is thought to be involved in bacterial stress responses, such as those associated with virulence, temperature, and symbiosis. Thus, BipA is necessary for securing bacterial survival and successful invasion of the host. Steady-state kinetic analysis and pelleting assays were used to assess the GTPase and ribosome-binding properties of S. enterica BipA. Under normal bacterial growth, BipA associates with the ribosome in the GTP-bound state. However, using sucrose density gradients, we demonstrate that the association of BipA and the ribosome is altered under stress conditions in bacteria similar to those experienced during virulence. The data show that this differential binding is brought about by the presence of ppGpp, an alarmone that signals the onset of stress-related events in bacteria.

  8. Differential Responses of Macrophages to Salmonella enterica Serovars Enteritidis and Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophages are major effectors against Salmonella infection, and also transport bacteria between host tissues and provide a protected site for intracellular bacterial replication. We hypothesized that differences in chicken macrophage responses to Salmonella enterica serovar Enteritidis (SE) and s...

  9. Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy

    PubMed Central

    Frahm, Michael; Kocijancic, Dino; Rohde, Manfred; Hensel, Michael; Curtiss, Roy; Erhardt, Marc; Weiss, Siegfried

    2015-01-01

    ABSTRACT Increasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria like Salmonella enterica serovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenic S. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbB mutants) of Salmonella were investigated for efficiency in tumor therapy. Of such variants, the ΔrfaD and ΔrfaG deep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into the araBAD locus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium. PMID:25873375

  10. MdsABC-Mediated Pathway for Pathogenicity in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Song, Saemee; Lee, Boeun; Yeom, Ji-Hyun; Hwang, Soonhye; Kang, Ilnam; Cho, Jang-Cheon; Ha, Nam-Chul; Bae, Jeehyeon

    2015-01-01

    MdsABC is a Salmonella-specific tripartite efflux pump that has been implicated in the virulence of Salmonella enterica serovar Typhimurium; however, little is known about the virulence factors associated with this pump. We observed MdsABC expression-dependent alterations in the degree of resistance to extracellular oxidative stress and macrophage-mediated killing. Thin-layer chromatography and tandem mass spectrometry analyses revealed that overexpression of MdsABC led to increased secretion of 1-palmitoyl-2-stearoyl-phosphatidylserine (PSPS), affecting the ability of the bacteria to invade and survive in host cells. Overexpression of MdsABC and external addition of PSPS similarly rendered the mdsABC deletion strain resistant to diamide. Diagonal gel analysis showed that PSPS treatment reduced the diamide-mediated formation of disulfide bonds, particularly in the membrane fraction of the bacteria. Salmonella infection of macrophages induced the upregulation of MdsABC expression and led to an increase of intracellular bacterial number and host cell death, similar to the effects of MdsABC overexpression and PSPS pretreatment on the mdsABC deletion strain. Our study shows that MdsABC mediates a previously uncharacterized pathway that involves PSPS as a key factor for the survival and virulence of S. Typhimurium in phagocytic cells. PMID:26283336

  11. Rescuing chemotaxis of the anticancer agent Salmonella enterica serovar Typhimurium VNP20009.

    PubMed

    Broadway, Katherine M; Denson, Elizabeth A P; Jensen, Roderick V; Scharf, Birgit E

    2015-10-10

    The role of chemotaxis and motility in Salmonella enterica serovar Typhimurium tumor colonization remains unclear. We determined through swim plate assays that the well-established anticancer agent S. Typhimurium VNP20009 is deficient in chemotaxis, and that this phenotype is suppressible. Through genome sequencing, we revealed that VNP20009 and four selected suppressor mutants had a single nucleotide polymorphism (SNP) in cheY causing a mutation in the conserved proline residue at position 110. CheY is the response regulator that interacts with the flagellar motor-switch complex and modulates rotational bias. The four suppressor mutants additionally carried non-synonymous SNPs in fliM encoding a flagellar switch protein. The CheY-P110S mutation in VNP20009 likely rendered the protein unable to interact with FliM, a phenotype that could be suppressed by mutations in FliM. We replaced the mutated cheY in VNP20009 with the wild-type copy and chemotaxis was partially restored. The swim ring of the rescued strain, VNP20009 cheY(+), was 46% the size of the parental strain 14028 swim ring. When tested in capillary assays, VNP20009 cheY(+) was 69% efficient in chemotaxis towards the attractant aspartate as compared to 14028. Potential reasons for the lack of complete restoration and implications for bacterial tumor colonization will be discussed. PMID:26200833

  12. LeuO is a global regulator of gene expression in Salmonella enterica serovar Typhimurium.

    PubMed

    Dillon, Shane C; Espinosa, Elena; Hokamp, Karsten; Ussery, David W; Casadesús, Josep; Dorman, Charles J

    2012-09-01

    We report the first investigation of the binding of the Salmonella enterica LeuO LysR-type transcription regulator to its genomic targets in vivo. Chromatin-immunoprecipitation-on-chip identified 178 LeuO binding sites on the chromosome of S. enterica serovar Typhimurium strain SL1344. These sites were distributed across both the core and the horizontally acquired genome, and included housekeeping genes and genes known to contribute to virulence. Sixty-eight LeuO targets were co-bound by the global repressor protein, H-NS. Thus, while LeuO may function as an H-NS antagonist, these functions are unlikely to involve displacement of H-NS. RNA polymerase bound 173 of the 178 LeuO targets, consistent with LeuO being a transcription regulator. Thus, LeuO targets two classes of genes, those that are bound by H-NS and those that are not bound by H-NS. LeuO binding site analysis revealed a logo conforming to the TN(11) A motif common to LysR-type transcription factors. It differed in some details from a motif that we composed for Escherichia coli LeuO binding sites; 1263 and 1094 LeuO binding site locations were predicted in the S. Typhimurium SL1344 and E. coli MG1655 genomes respectively. Despite differences in motif composition, many LeuO target genes were common to both species. Thus, LeuO is likely to be a more important global regulator than previously suspected. PMID:22804842

  13. Increased efficacy of inactivated vaccine candidates prepared with Salmonella enterica serovar Typhimurium strains of predominant genotypes in ducks.

    PubMed

    Youn, S Y; Kwon, Y K; Song, C S; Lee, H J; Jeong, O M; Choi, B K; Jung, S C; Kang, M S

    2016-08-01

    Salmonella enterica serovar Typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. In particular, ducks serve as a reservoir of serovar Typhimurium, and are one of the common sources of human infection. To prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. Here, we analyzed the genetic diversity and virulence of serovar Typhimurium isolates from ducks in Korea to identify the predominant strains that might be used as efficient vaccine candidates for ducks. Among the isolates, 2 representative isolates (ST26 and ST76) of predominant genotypes were selected as vaccine strains on the basis of genotypic analysis by pulsed-field gel electrophoresis and DNA microarrays. Two-week-old ducks were then injected intramuscularly with inactivated vaccine candidates prepared using ST26 or ST76 (10(8) cfu/0.5 mL/duck or 10(9) cfu/0.5 mL/duck), and oral challenge with a highly virulent serovar Typhimurium strain (10(9) cfu/0.5 mL/duck) was carried out 2 wk later. Shedding of the challenge strain was significantly decreased in group 2 after vaccination. The antibody levels by enzyme-linked immunosorbent assay in all vaccinated groups were enhanced significantly (P < 0.05) compared to the unvaccinated control group. Overall, vaccination with ST26 or ST76 reduced bacterial shedding and colonization in internal organs, and induced elevated antibody response. In particular, serovar Typhimurium ST26 (10(8) cfu/0.5 mL/duck) was the most effective vaccine candidate, which can provide efficient protection against serovar Typhimurium in ducks with higher effectiveness compared to a commercial vaccine currently used worldwide. PMID:26994209

  14. A comparative study of thermal and acid inactivation kinetics in fruit juices of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Senftenberg grown at acidic conditions.

    PubMed

    Alvarez-Ordóñez, Avelino; Fernández, Ana; Bernardo, Ana; López, Mercedes

    2009-11-01

    Acid and heat inactivation in orange and apple juices of Salmonella enterica serovar Typhimurium Colección Española de Cultivos Tipo (i.e., Spanish Type Culture Collection) 443 (CECT 443) (Salmonella Typhimurium) and S. enterica serovar Senftenberg CECT 4384 (Salmonella Senftenberg) grown in buffered brain heart infusion (pH 7.0) and acidified brain heart infusion up to pH 4.5 with acetic, citric, lactic, and hydrochloric acids was evaluated. Acid adaptation induced an adaptive response that increased the subsequent resistance to extreme pH conditions (pH 2.5) and to heat, although the magnitude of these responses differed between the two isolates and fruit juices. The acid resistance in orange juice for acid-adapted cells (D-values of 28.3-34.5 min for Salmonella Senftenberg and 30.0-39.2 min for Salmonella Typhimurium) resulted to be about two to three times higher than that corresponding to non-acid-adapted cells. In apple juice, acid-adapted Salmonella Senftenberg cells survived better than those of Salmonella Typhimurium, obtaining mean D-values of 114.8 +/- 12.3 and 41.9 +/- 2.5 min, respectively. The thermotolerance of non-acid-adapted Salmonella Typhimurium in orange (D(58)-value: 0.028 min) and apple juices (D(58)-value: 0.10 min) was approximately double for acid-adapted cells. This cross-protection to heat was more strongly expressed in Salmonella Senftenberg. D(58)-values obtained for non-acid-adapted cells in orange (0.11 min) and apple juices (0.19 min) increased approximately 10 and 5 times, respectively, after their growth in acidified media. The conditions prevailing during bacterial growth and heat treatment did not significantly influence the z-values observed (6.0 +/- 0.3 degrees C for Salmonella Typhimurium and 7.0 +/- 0.3 degrees C for Salmonella Senftenberg). The enhanced acid resistance found for both isolates could enable them to survive for prolonged time periods in the gastrointestinal tract, increasing the risk of illness. Further, it

  15. Complete genome sequencing of a multidrug-resistant and human-invasive Salmonella enterica serovar Typhimurium strain of the emerging sequence type 213 genotype

    DOE PAGESBeta

    Calva, Edmundo; Silva, Claudia; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.; et al

    2015-06-18

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids.

  16. Complete Genome Sequencing of a Multidrug-Resistant and Human-Invasive Salmonella enterica Serovar Typhimurium Strain of the Emerging Sequence Type 213 Genotype

    PubMed Central

    Calva, Edmundo; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids. PMID:26089426

  17. Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain YU15 (Sequence Type 19) Harboring the Salmonella Genomic Island 1 and Virulence Plasmid pSTV

    PubMed Central

    Calva, Edmundo; Puente, José L.; Zaidi, Mussaret B.

    2016-01-01

    The complete genome of Salmonella enterica subsp. enterica serovar Typhimurium sequence type 19 (ST19) strain YU15, isolated in Yucatán, Mexico, from a human baby stool culture, was determined using PacBio technology. The chromosome contains five intact prophages and the Salmonella genomic island 1 (SGI1). This strain carries the Salmonella virulence plasmid pSTV. PMID:27081132

  18. The complete plasmid sequences of Salmonella enterica serovar Typhimurium U288.

    PubMed

    Hooton, Steven P T; Timms, Andrew R; Cummings, Nicola J; Moreton, Joanna; Wilson, Ray; Connerton, Ian F

    2014-08-28

    Salmonella enterica Serovar Typhimurium U288 is an emerging pathogen of pigs. The strain contains three plasmids of diverse origin that encode traits that are of concern for food security and safety, these include antibiotic resistant determinants, an array of functions that can modify cell physiology and permit genetic mobility. At 148,711 bp, pSTU288-1 appears to be a hybrid plasmid containing a conglomerate of genes found in pSLT of S. Typhimurium LT2, coupled with a mosaic of horizontally-acquired elements. Class I integron containing gene cassettes conferring resistance against clinically important antibiotics and compounds are present in pSTU288-1. A curious feature of the plasmid involves the deletion of two genes encoded in the Salmonella plasmid virulence operon (spvR and spvA) following the insertion of a tnpA IS26-like element coupled to a blaTEM gene. The spv operon is considered to be a major plasmid-encoded Salmonella virulence factor that is essential for the intracellular lifecycle. The loss of the positive regulator SpvR may impact on the pathogenesis of S. Typhimurium U288. A second 11,067 bp plasmid designated pSTU288-2 contains further antibiotic resistance determinants, as well as replication and mobilization genes. Finally, a small 4675 bp plasmid pSTU288-3 was identified containing mobilization genes and a pleD-like G-G-D/E-E-F conserved domain protein that modulate intracellular levels of cyclic di-GMP, and are associated with motile to sessile transitions in growth. PMID:25175817

  19. The QseB Response Regulator is Required for Decreased Bacterial Motility and Swine Colonization in a QseC Mutant of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inactivation of the QseC (PreB) sensor kinase decreases the motility of a qseC mutant compared to wild-type Salmonella enterica serovar Typhimurium (S. Typhimurium). In addition, the competitive fitness of the qseC mutant for colonization of the swine gastrointestinal tract is decreased compared to...

  20. Upregulation of STM3175 Decreases Bacterial Motility and Swine Colonization in a qseC (preB) Mutant of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inactivation of the QseC (PreB) sensor kinase decreases bacterial motility and pathogen colonization of the swine gastrointestinal tract for Salmonella enterica serovar Typhimurium (S. Typhimurium). In contrast, both the qseB [encoding the QseB (PreA) response regulator] and qseBC mutants had motil...

  1. A Mutation in the PoxA Gene of Salmonella enterica Serovar Typhimurium Results in Altered Protein Production, Elevated Susceptibility to Environmental Challenges, and Decreased Swine Colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using signature-tagged mutagenesis of Salmonella enterica serovar Typhimurium (S. Typhimurium), a mutation in the poxA gene (STM4344; yjeA; poxR), encoding a putative lysyl-tRNA synthetase, was previously identified by our research group which caused decreased survival in an ex vivo swine stomach co...

  2. Iron regulated genes of Salmonella enterica serovar Typhimurium in response to norepinephrine and the requirement of fepCDG for norepinephrine-enhanced growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of catecholamines in vivo may stimulate enteric bacteria including the foodborne pathogen Salmonella enterica serovar Typhimurium by two mechanisms, acting as a quorum sensing signal and providing iron in the presence of serum. To identify genes of Salmonella Typhimurium that participa...

  3. The Salmonella enterica serovar Typhimurium QseB Response Regulator Negatively Regulates Bacterial Motility and Swine Colonization in the Absence of the QseC Sensor Kinase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (S. Typhimurium) responds to the catecholamine, norepinephrine by increasing bacterial growth and enhancing motility. In this study, iron with or without the siderophore, ferrioxamine E also enhanced bacterial motility. Iron-enhanced motility was growth-rate ...

  4. Characterization of the Genomes of a Diverse Collection of Salmonella enterica Serovar Typhimurium Definitive Phage Type 104▿

    PubMed Central

    Cooke, Fiona J.; Brown, Derek J.; Fookes, Maria; Pickard, Derek; Ivens, Alasdair; Wain, John; Roberts, Mark; Kingsley, Robert A.; Thomson, Nicholas R.; Dougan, Gordon

    2008-01-01

    Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We completed the full DNA sequence of one DT104 strain, NCTC13348, and showed that significant differences between the genome of this isolate and the genome of the previously sequenced strain Salmonella serovar Typhimurium LT2 are due to integrated prophage elements and Salmonella genomic island 1 encoding antibiotic resistance genes. Thirteen isolates of Salmonella serovar Typhimurium DT104 with different pulsed-field gel electrophoresis (PFGE) profiles were analyzed by using multilocus sequence typing (MLST), plasmid profiling, hybridization to a pan-Salmonella DNA microarray, and prophage-based multiplex PCR. All the isolates belonged to a single MLST type, sequence type ST19. Microarray data demonstrated that the gene contents of the 13 DT104 isolates were remarkably conserved. The PFGE DNA fragment size differences in these isolates could be explained to a great extent by differences in the prophage and plasmid contents. Thus, here the nature of variation in different Salmonella serovar Typhimurium DT104 isolates is further defined at the gene and whole-genome levels, illustrating how this phage type evolves over time. PMID:18849424

  5. Multiple antibiotic resistance (mar) locus in Salmonella enterica serovar typhimurium DT104.

    PubMed

    Randall, L P; Woodward, M J

    2001-03-01

    In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicylate induced marA, whereas a number of antibiotics, disinfectants, and various growth conditions did not. Increased antibiotic resistance was observed upon salicylate induction, although this was shown to be by both mar-dependent and mar-independent pathways. Cyclohexane resistance, however, was induced by salicylate by a mar-dependent pathway. Complementation studies with a plasmid that constitutively expressed marA confirmed the involvement of mar in Salmonella with low-level antibiotic resistance and cyclohexane resistance, although the involvement of mar in down regulation of OmpF was unclear. However, marA overexpression did increase the expression of a ca. 50-kDa protein, but its identity remains to be elucidated. Passage of the marA::gfp reporter mutant with increasing levels of tetracycline, a method reported to select for mar mutants in Escherichia coli, led to both multiple-antibiotic and cyclohexane resistance. Collectively, these data indicate that low-level antibiotic resistance, cyclohexane resistance, and modulation of OMPs in Salmonella, as in E. coli, can occur in both a mar-dependent and mar-independent manner. PMID:11229910

  6. Temperate phages promote colicin-dependent fitness of Salmonella enterica serovar Typhimurium.

    PubMed

    Nedialkova, Lubov P; Sidstedt, Maja; Koeppel, Martin B; Spriewald, Stefanie; Ring, Diana; Gerlach, Roman G; Bossi, Lionello; Stecher, Bärbel

    2016-05-01

    Bacteria employ bacteriocins for interference competition in microbial ecosystems. Colicin Ib (ColIb), a pore-forming bacteriocin, confers a significant fitness benefit to Salmonella enterica serovar Typhimurium (S. Tm) in competition against commensal Escherichia coli in the gut. ColIb is released from S. Tm into the environment, where it kills susceptible competitors. However, colicin-specific release proteins, as they are known for other colicins, have not been identified in case of ColIb. Thus, its release mechanism has remained unclear. In the current study, we have established a new link between ColIb release and lysis activity of temperate, lambdoid phages. By the use of phage-cured S. Tm mutant strains, we show that the presence of temperate phages and their lysis genes is necessary and sufficient for release of active ColIb into the culture supernatant. Furthermore, phage-mediated lysis significantly enhanced S. Tm fitness in competition against a ColIb-susceptible competitor. Finally, transduction with the lambdoid phage 933W rescued the defect of E. coli strain MG1655 with respect to ColIb release. In conclusion, ColIb is released from bacteria in the course of phage lysis. Our data reveal a new mechanism for colicin release and point out a novel function of temperate phages in enhancing colicin-dependent bacterial fitness. PMID:26439675

  7. Salmonella enterica Serovar Typhimurium Skills To Succeed in the Host: Virulence and Regulation

    PubMed Central

    Fàbrega, Anna

    2013-01-01

    SUMMARY Salmonella enterica serovar Typhimurium is a primary enteric pathogen infecting both humans and animals. Infection begins with the ingestion of contaminated food or water so that salmonellae reach the intestinal epithelium and trigger gastrointestinal disease. In some patients the infection spreads upon invasion of the intestinal epithelium, internalization within phagocytes, and subsequent dissemination. In that case, antimicrobial therapy, based on fluoroquinolones and expanded-spectrum cephalosporins as the current drugs of choice, is indicated. To accomplish the pathogenic process, the Salmonella chromosome comprises several virulence mechanisms. The most important virulence genes are those located within the so-called Salmonella pathogenicity islands (SPIs). Thus far, five SPIs have been reported to have a major contribution to pathogenesis. Nonetheless, further virulence traits, such as the pSLT virulence plasmid, adhesins, flagella, and biofilm-related proteins, also contribute to success within the host. Several regulatory mechanisms which synchronize all these elements in order to guarantee bacterial survival have been described. These mechanisms govern the transitions from the different pathogenic stages and drive the pathogen to achieve maximal efficiency inside the host. This review focuses primarily on the virulence armamentarium of this pathogen and the extremely complicated regulatory network controlling its success. PMID:23554419

  8. Selection of Orphan Rhs Toxin Expression in Evolved Salmonella enterica Serovar Typhimurium

    PubMed Central

    Koskiniemi, Sanna; Garza-Sánchez, Fernando; Sandegren, Linus; Webb, Julia S.; Braaten, Bruce A.; Poole, Stephen J.; Andersson, Dan I.; Hayes, Christopher S.; Low, David A.

    2014-01-01

    Clonally derived bacterial populations exhibit significant genotypic and phenotypic diversity that contribute to fitness in rapidly changing environments. Here, we show that serial passage of Salmonella enterica serovar Typhimurium LT2 (StLT2) in broth, or within a mouse host, results in selection of an evolved population that inhibits the growth of ancestral cells by direct contact. Cells within each evolved population gain the ability to express and deploy a cryptic “orphan” toxin encoded within the rearrangement hotspot (rhs) locus. The Rhs orphan toxin is encoded by a gene fragment located downstream of the “main” rhs gene in the ancestral strain StLT2. The Rhs orphan coding sequence is linked to an immunity gene, which encodes an immunity protein that specifically blocks Rhs orphan toxin activity. Expression of the Rhs orphan immunity protein protects ancestral cells from the evolved lineages, indicating that orphan toxin activity is responsible for the observed growth inhibition. Because the Rhs orphan toxin is encoded by a fragmented reading frame, it lacks translation initiation and protein export signals. We provide evidence that evolved cells undergo recombination between the main rhs gene and the rhs orphan toxin gene fragment, yielding a fusion that enables expression and delivery of the orphan toxin. In this manner, rhs locus rearrangement provides a selective advantage to a subpopulation of cells. These observations suggest that rhs genes play important roles in intra-species competition and bacterial evolution. PMID:24675981

  9. Evidence for an Efflux Pump Mediating Multiple Antibiotic Resistance in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Piddock, Laura J. V.; White, David G.; Gensberg, Karl; Pumbwe, Lilian; Griggs, Deborah J.

    2000-01-01

    The mechanism of multiple antibiotic resistance in six isolates of Salmonella enterica serovar Typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of efflux in the resistance phenotype. Compared to the patient's pretherapy isolate (L3), five of six isolates accumulated less ciprofloxacin, three of six isolates accumulated less chloramphenicol, and all six accumulated less tetracycline. The accumulation of one or more antibiotics was increased by carbonyl cyanide m-chlorophenylhydrazone to concentrations similar to those accumulated by L3 for all isolates except one, in which accumulation of all three agents remained approximately half that of L3. All isolates had the published wild-type sequences of marO and marR. No increased expression of marA, tolC, or soxS was observed by Northern blotting; however, three isolates showed increased expression of acrB, which was confirmed by quantitative competitive reverse transcription-PCR. However, there were no mutations within acrR or the promoter region of acrAB in any of the isolates. PMID:11036033

  10. Licoflavonol is an inhibitor of the type three secretion system of Salmonella enterica serovar Typhimurium.

    PubMed

    Guo, Zhixing; Li, Xiaoli; Li, Jianfang; Yang, Xuefei; Zhou, Yuan; Lu, Chunhua; Shen, Yuemao

    2016-09-01

    As an important food-borne human pathogen, Salmonella enterica serovar Typhimurium depends on its type III secretion system (T3SS) as a major virulence factor to cause disease all over the world. The T3SS secretes effector proteins to facilitate invasion into host cells. In this study, twenty prenylated flavonoids (1-20) were screened for their anti-T3SS activity, revealing that several analogs exhibited strong inhibitory effects on the secretion of Salmonella pathogenicity island 1 (SPI-1)-associated effector proteins without affecting the growth of bacteria and the secretion of the flagellar protein FliC. Among the flavonoids 1-20, licoflavonol (20) exhibited a strong inhibitory effect on the secretion of the SPI-1 effector proteins via regulating the transcription of the SicA/InvF genes, and the transportation of the effector protein SipC. In summary, licoflavonol, a novel natural inhibitor of Salmonella T3SS, could be a promising candidate for novel type of anti-virulence drugs. PMID:27387231

  11. Cost-Effective Application of Pulsed-Field Gel Electrophoresis to Typing of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Doran, Geraldine; Morris, Dearbhaile; O'Hare, Colette; DeLappe, Niall; Bradshaw, Bernard; Corbett-Feeney, Geraldine; Cormican, Martin

    2005-01-01

    Salmonella enterica serovar Typhimurium is frequently isolated from humans and animals. Phage typing is historically the first-line reference typing technique in Europe. It is rapid and convenient for laboratories with appropriate training and experience, and costs of consumables are low. Phage typing and pulsed-field gel electrophoresis (PFGE) were performed on 503 isolates of serovar Typhimurium. Twenty-nine phage types and 53 PFGE patterns were observed. Most isolates of phage types DT104, DT104b, and U310 are not distinguishable from other members of their phage type by PFGE. By contrast, PFGE of isolates of phage types DT193 and U302 shows great heterogeneity. Analysis of experience with PFGE and phage typing can facilitate the selective application of PFGE to maximize the yield of epidemiologically relevant additional information while controlling costs. PMID:16332808

  12. Salmonella enterica serovar Typhimurium lacking hfq gene confers protective immunity against murine typhoid.

    PubMed

    Allam, Uday Shankar; Krishna, M Gopala; Lahiri, Amit; Joy, Omana; Chakravortty, Dipshikha

    2011-01-01

    Salmonella enterica is an important enteric pathogen and its various serovars are involved in causing both systemic and intestinal diseases in humans and domestic animals. The emergence of multidrug-resistant strains of Salmonella leading to increased morbidity and mortality has further complicated its management. Live attenuated vaccines have been proven superior over killed or subunit vaccines due to their ability to induce protective immunity. Of the various strategies used for the generation of live attenuated vaccine strains, focus has gradually shifted towards manipulation of virulence regulator genes. Hfq is a RNA chaperon which mediates the binding of small RNAs to the mRNA and assists in post-transcriptional gene regulation in bacteria. In this study, we evaluated the efficacy of the Salmonella Typhimurium Δhfq strain as a candidate for live oral vaccine in murine model of typhoid fever. Salmonella hfq deletion mutant is highly attenuated in cell culture and animal model implying a significant role of Hfq in bacterial virulence. Oral immunization with the Salmonella hfq deletion mutant efficiently protects mice against subsequent oral challenge with virulent strain of Salmonella Typhimurium. Moreover, protection was induced upon both multiple as well as single dose of immunizations. The vaccine strain appears to be safe for use in pregnant mice and the protection is mediated by the increase in the number of CD4(+) T lymphocytes upon vaccination. The levels of serum IgG and secretory-IgA in intestinal washes specific to lipopolysaccharide and outer membrane protein were significantly increased upon vaccination. Furthermore, hfq deletion mutant showed enhanced antigen presentation by dendritic cells compared to the wild type strain. Taken together, the studies in murine immunization model suggest that the Salmonella hfq deletion mutant can be a novel live oral vaccine candidate. PMID:21347426

  13. Replication of Salmonella enterica Serovar Typhimurium in Human Monocyte-Derived Macrophages.

    PubMed

    Lathrop, Stephanie K; Binder, Kelsey A; Starr, Tregei; Cooper, Kendal G; Chong, Audrey; Carmody, Aaron B; Steele-Mortimer, Olivia

    2015-07-01

    Salmonella enterica serovar Typhimurium is a common cause of food-borne gastrointestinal illness, but additionally it causes potentially fatal bacteremia in some immunocompromised patients. In mice, systemic spread and replication of the bacteria depend upon infection of and replication within macrophages, but replication in human macrophages is not widely reported or well studied. In order to assess the ability of Salmonella Typhimurium to replicate in human macrophages, we infected primary monocyte-derived macrophages (MDM) that had been differentiated under conditions known to generate different phenotypes. We found that replication in MDM depends greatly upon the phenotype of the cells, as M1-skewed macrophages did not allow replication, while M2a macrophages and macrophages differentiated with macrophage colony-stimulating factor (M-CSF) alone (termed M0) did. We describe how additional conditions that alter the macrophage phenotype or the gene expression of the bacteria affect the outcome of infection. In M0 MDM, the temporal expression of representative genes from Salmonella pathogenicity islands 1 and 2 (SPI1 and SPI2) and the importance of the PhoP/Q two-component regulatory system are similar to what has been shown in mouse macrophages. However, in contrast to mouse macrophages, where replication is SPI2 dependent, we observed early SPI2-independent replication in addition to later SPI2-dependent replication in M0 macrophages. Only SPI2-dependent replication was associated with death of the host cell at later time points. Altogether, our results reveal a very nuanced interaction between Salmonella and human macrophages. PMID:25895967

  14. Sub-Inhibitory Fosmidomycin Exposures Elicits Oxidative Stress in Salmonella enterica Serovar typhimurium LT2

    PubMed Central

    Fox, David T.; Schmidt, Emily N.; Tian, Hongzhao; Dhungana, Suraj; Valentine, Michael C.; Warrington, Nicole V.; Phillips, Paul D.; Finney, Kellan B.; Cope, Emily K.; Leid, Jeff G.; Testa, Charles A.; Koppisch, Andrew T.

    2014-01-01

    Fosmidomycin is a time-dependent nanomolar inhibitor of methylerythritol phosphate (MEP) synthase, which is the enzyme that catalyzes the first committed step in the MEP pathway to isoprenoids. Importantly, fosmidomycin is one of only a few MEP pathway-specific inhibitors that exhibits antimicrobial activity. Most inhibitors identified to date only exhibit activity against isolated pathway enzymes. The MEP pathway is the sole route to isoprenoids in many bacteria, yet has no human homologs. The development of inhibitors of this pathway holds promise as novel antimicrobial agents. Similarly, analyses of the bacterial response toward MEP pathway inhibitors provides valuable information toward the understanding of how emergent resistance may ultimately develop to this class of antibiotics. We have examined the transcriptional response of Salmonella enterica serovar typhimurium LT2 to sub-inhibitory concentrations of fosmidomycin via cDNA microarray and RT-PCR. Within the regulated genes identified by microarray were a number of genes encoding enzymes associated with the mediation of reactive oxygen species (ROS). Regulation of a panel of genes implicated in the response of cells to oxidative stress (including genes for catalases, superoxide dismutases, and alkylhydrogen peroxide reductases) was investigated and mild upregulation in some members was observed as a function of fosmidomycin exposure over time. The extent of regulation of these genes was similar to that observed for comparable exposures to kanamycin, but differed significantly from tetracycline. Furthermore, S. typhimurium exposed to sub-inhibitory concentrations of fosmidomycin displayed an increased sensitivity to exogenous H2O2 relative to either untreated controls or kanamycin-treated cells. Our results suggest that endogenous oxidative stress is one consequence of exposures to fosmidomycin, likely through the temporal depletion of intracellular isoprenoids themselves, rather than other mechanisms that

  15. Replication of Salmonella enterica Serovar Typhimurium in Human Monocyte-Derived Macrophages

    PubMed Central

    Lathrop, Stephanie K.; Binder, Kelsey A.; Starr, Tregei; Cooper, Kendal G.; Chong, Audrey; Carmody, Aaron B.

    2015-01-01

    Salmonella enterica serovar Typhimurium is a common cause of food-borne gastrointestinal illness, but additionally it causes potentially fatal bacteremia in some immunocompromised patients. In mice, systemic spread and replication of the bacteria depend upon infection of and replication within macrophages, but replication in human macrophages is not widely reported or well studied. In order to assess the ability of Salmonella Typhimurium to replicate in human macrophages, we infected primary monocyte-derived macrophages (MDM) that had been differentiated under conditions known to generate different phenotypes. We found that replication in MDM depends greatly upon the phenotype of the cells, as M1-skewed macrophages did not allow replication, while M2a macrophages and macrophages differentiated with macrophage colony-stimulating factor (M-CSF) alone (termed M0) did. We describe how additional conditions that alter the macrophage phenotype or the gene expression of the bacteria affect the outcome of infection. In M0 MDM, the temporal expression of representative genes from Salmonella pathogenicity islands 1 and 2 (SPI1 and SPI2) and the importance of the PhoP/Q two-component regulatory system are similar to what has been shown in mouse macrophages. However, in contrast to mouse macrophages, where replication is SPI2 dependent, we observed early SPI2-independent replication in addition to later SPI2-dependent replication in M0 macrophages. Only SPI2-dependent replication was associated with death of the host cell at later time points. Altogether, our results reveal a very nuanced interaction between Salmonella and human macrophages. PMID:25895967

  16. Contribution of Target Gene Mutations and Efflux to Decreased Susceptibility of Salmonella enterica Serovar Typhimurium to Fluoroquinolones and Other Antimicrobials▿

    PubMed Central

    Chen, Sheng; Cui, Shenghui; McDermott, Patrick F.; Zhao, Shaohua; White, David G.; Paulsen, Ian; Meng, Jianghong

    2007-01-01

    The mechanisms involved in fluoroquinolone resistance in Salmonella enterica include target alterations and overexpression of efflux pumps. The present study evaluated the role of known and putative multidrug resistance efflux pumps and mutations in topoisomerase genes among laboratory-selected and naturally occurring fluoroquinolone-resistant Salmonella enterica serovar Typhimurium strains. Strains with ciprofloxacin MICs of 0.25, 4, 32, and 256 μg/ml were derived in vitro using serovar Typhimurium S21. These mutants also showed decreased susceptibility or resistance to many nonfluoroquinolone antimicrobials, including tetracycline, chloramphenicol, and several β-lactams. The expression of efflux pump genes acrA, acrB, acrE, acrF, emrB, emrD, and mdlB were substantially increased (≥2-fold) among the fluoroquinolone-resistant mutants. Increased expression was also observed, but to a lesser extent, with three other putative efflux pumps: mdtB (yegN), mdtC (yegO), and emrA among mutants with ciprofloxacin MICs of ≥32 μg/ml. Deletion of acrAB or tolC in S21 and its fluoroquinolone-resistant mutants resulted in increased susceptibility to fluoroquinolones and other tested antimicrobials. In naturally occurring fluoroquinolone-resistant serovar Typhimurium strains, deletion of acrAB or tolC increased fluoroquinolone susceptibility 4-fold, whereas replacement of gyrA double mutations (S83F D87N) with wild-type gyrA increased susceptibility >500-fold. These results indicate that a combination of topoisomerase gene mutations, as well as enhanced antimicrobial efflux, plays a critical role in the development of fluoroquinolone resistance in both laboratory-derived and naturally occurring quinolone-resistant serovar Typhimurium strains. PMID:17043131

  17. Integrative Analysis of Salmonellosis in Israel Reveals Association of Salmonella enterica Serovar 9,12:l,v:− with Extraintestinal Infections, Dissemination of Endemic S. enterica Serovar Typhimurium DT104 Biotypes, and Severe Underreporting of Outbreaks

    PubMed Central

    Marzel, Alex; Desai, Prerak T.; Nissan, Israel; Schorr, Yosef Ilan; Suez, Jotham; Valinsky, Lea; Reisfeld, Abraham; Agmon, Vered; Guard, Jean; McClelland, Michael

    2014-01-01

    Salmonella enterica is the leading etiologic agent of bacterial food-borne outbreaks worldwide. This ubiquitous species contains more than 2,600 serovars that may differ in their host specificity, clinical manifestations, and epidemiology. To characterize salmonellosis epidemiology in Israel and to study the association of nontyphoidal Salmonella (NTS) serovars with invasive infections, 48,345 Salmonella cases reported and serotyped at the National Salmonella Reference Center between 1995 and 2012 were analyzed. A quasi-Poisson regression was used to identify irregular clusters of illness, and pulsed-field gel electrophoresis in conjunction with whole-genome sequencing was applied to molecularly characterize strains of interest. Three hundred twenty-nine human salmonellosis clusters were identified, representing an annual average of 23 (95% confidence interval [CI], 20 to 26) potential outbreaks. We show that the previously unsequenced S. enterica serovar 9,12:l,v:− belongs to the B clade of Salmonella enterica subspecies enterica, and we show its frequent association with extraintestinal infections, compared to other NTS serovars. Furthermore, we identified the dissemination of two prevalent Salmonella enterica serovar Typhimurium DT104 clones in Israel, which are genetically distinct from other global DT104 isolates. Accumulatively, these findings indicate a severe underreporting of Salmonella outbreaks in Israel and provide insights into the epidemiology and genomics of prevalent serovars, responsible for recurring illness. PMID:24719441

  18. Salmonella enterica serovar Typhimurium-induced placental inflammation and not bacterial burden correlates with pathology and fatal maternal disease.

    PubMed

    Chattopadhyay, Anindita; Robinson, Nirmal; Sandhu, Jagdeep K; Finlay, B Brett; Sad, Subash; Krishnan, Lakshmi

    2010-05-01

    Food-borne infections caused by Salmonella enterica species are increasing globally, and pregnancy poses a high risk. Pregnant mice rapidly succumb to S. enterica serovar Typhimurium infection. To determine the mechanisms involved, we addressed the role of inflammation and bacterial burden in causing placental and systemic disease. In vitro, choriocarcinoma cells were a highly conducive niche for intracellular S. Typhimurium proliferation. While infection of mice with S. Typhimurium wild-type (WT) and mutant (Delta aroA and Delta invA) strains led to profound pathogen proliferation and massive burden within placental cells, only the virulent WT S. Typhimurium infection evoked total fetal loss and adverse host outcome. This correlated with substantial placental expression of granulocyte colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) and increased serum inflammatory cytokines/chemokines, such as G-CSF, IL-6, CCL1, and KC, evoked by WT S. Typhimurium infection. In contrast, infection with high doses of S. Typhimurium Delta aroA, despite causing massive placental infection, resulted in reduced inflammatory cellular and cytokine response. While S. Typhimurium WT bacteria were dispersed in large numbers across all regions of the placenta, including the deeper labyrinth trophoblast, S. Typhimurium Delta aroA bacteria localized primarily to the decidua. This correlated with the widespread placental necrosis accompanied by neutrophil infiltration evoked by the S. Typhimurium WT bacteria. Thus, the ability of Salmonella to localize to deeper layers of the placenta and the nature of inflammation triggered by the pathogen, rather than bacterial burden, profoundly influenced placental integrity and host survival. PMID:20194592

  19. Effects of indole on drug resistance and virulence of Salmonella enterica serovar Typhimurium revealed by genome-wide analyses

    PubMed Central

    2012-01-01

    Background Many Gram-positive and Gram-negative bacteria produce large quantities of indole as an intercellular signal in microbial communities. Indole demonstrated to affect gene expression in Escherichia coli as an intra-species signaling molecule. In contrast to E. coli, Salmonella does not produce indole because it does not harbor tnaA, which encodes the enzyme responsible for tryptophan metabolism. Our previous study demonstrated that E. coli-conditioned medium and indole induce expression of the AcrAB multidrug efflux pump in Salmonella enterica serovar Typhimurium for inter-species communication; however, the global effect of indole on genes in Salmonella remains unknown. Results To understand the complete picture of genes regulated by indole, we performed DNA microarray analysis of genes in the S. enterica serovar Typhimurium strain ATCC 14028s affected by indole. Predicted Salmonella phenotypes affected by indole based on the microarray data were also examined in this study. Indole induced expression of genes related to efflux-mediated multidrug resistance, including ramA and acrAB, and repressed those related to host cell invasion encoded in the Salmonella pathogenicity island 1, and flagella production. Reduction of invasive activity and motility of Salmonella by indole was also observed phenotypically. Conclusion Our results suggest that indole is an important signaling molecule for inter-species communication to control drug resistance and virulence of S. enterica. PMID:22632036

  20. Epidemiology of plasmid-mediated quinolone resistance in salmonella enterica serovar typhimurium isolates from food-producing animals in Japan

    PubMed Central

    2010-01-01

    A total of 225 isolates of Salmonella enterica serovar Typhimurium from food-producing animals collected between 2003 and 2007 were examined for the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants, namely qnrA, qnrB, qnrC, qnrD, qnrS, qepA and aac(6')Ib-cr, in Japan. Two isolates (0.8%) of S. Typhimurium DT104 from different dairy cows on a single farm in 2006 and 2007 were found to have qnrS1 on a plasmid of approximately 9.6-kbp. None of the S. Typhimurium isolates had qnrA, qnrB, qnrC, qnrD, qepA and acc(6')-Ib-cr. Currently in Japan, the prevalence of the PMQR genes among S. Typhimurium isolates from food animals may remain low or restricted. The PFGE profile of two S. Typhimurium DT104 isolates without qnrS1 on the farm in 2005 had an identical PFGE profile to those of two S. Typhimurium DT104 isolates with qnrS1. The PFGE analysis suggested that the already existing S. Typhimurium DT104 on the farm fortuitously acquired the qnrS1 plasmid. PMID:21138594

  1. Genomic Comparison of Non-Typhoidal Salmonella enterica Serovars Typhimurium, Enteritidis, Heidelberg, Hadar and Kentucky Isolates from Broiler Chickens

    PubMed Central

    Dhanani, Akhilesh S.; Block, Glenn; Dewar, Ken; Forgetta, Vincenzo; Topp, Edward; Beiko, Robert G.; Diarra, Moussa S.

    2015-01-01

    Background Non-typhoidal Salmonella enterica serovars, associated with different foods including poultry products, are important causes of bacterial gastroenteritis worldwide. The colonization of the chicken gut by S. enterica could result in the contamination of the environment and food chain. The aim of this study was to compare the genomes of 25 S. enterica serovars isolated from broiler chicken farms to assess their intra- and inter-genetic variability, with a focus on virulence and antibiotic resistance characteristics. Methodology/Principal Finding The genomes of 25 S. enterica isolates covering five serovars (ten Typhimurium including three monophasic 4,[5],12:i:, four Enteritidis, three Hadar, four Heidelberg and four Kentucky) were sequenced. Most serovars were clustered in strongly supported phylogenetic clades, except for isolates of serovar Enteritidis that were scattered throughout the tree. Plasmids of varying sizes were detected in several isolates independently of serovars. Genes associated with the IncF plasmid and the IncI1 plasmid were identified in twelve and four isolates, respectively, while genes associated with the IncQ plasmid were found in one isolate. The presence of numerous genes associated with Salmonella pathogenicity islands (SPIs) was also confirmed. Components of the type III and IV secretion systems (T3SS and T4SS) varied in different isolates, which could explain in part, differences of their pathogenicity in humans and/or persistence in broilers. Conserved clusters of genes in the T3SS were detected that could be used in designing effective strategies (diagnostic, vaccination or treatments) to combat Salmonella. Antibiotic resistance genes (CMY, aadA, ampC, florR, sul1, sulI, tetAB, and srtA) and class I integrons were detected in resistant isolates while all isolates carried multidrug efflux pump systems regardless of their antibiotic susceptibility profile. Conclusions/Significance This study showed that the predominant

  2. Reporters for Single-Cell Analysis of Colicin Ib Expression in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Spriewald, Stefanie; Glaser, Jana; Beutler, Markus; Koeppel, Martin B.; Stecher, Bärbel

    2015-01-01

    Colicins are toxins that mediate interference competition in microbial ecosystems. They serve as a “common good” for the entire producer population but are synthesized by only few members which pay the costs of colicin production. We have previously shown that production of colicin Ib (cib), a group B colicin, confers a competitive advantage to Salmonella enterica serovar Typhimurium (S. Tm) over commensal E. coli strains. Here, we studied regulation of S. Tm cib expression at the single cell level. Comparative analysis of a single- and a multicopy gfp-reporter for the colicin Ib promoter (Pcib) revealed that the latter yielded optimal signal intensity for a diverse range of applications. We further validated this reporter and showed that gfp expression correlated well with colicin Ib (ColIb) protein levels in individual cells. Pcib is negatively controlled by two repressors, LexA and Fur. Only a small fraction of S. Tm expressed cib under non-inducing conditions. We studied Pcib activity in response to mitomycin C mediated DNA damage and iron limitation. Both conditions, if applied individually, lead to an increase in the fraction of GFP+ S. Tm, albeit an overall low fluorescence intensity. When both conditions were applied simultaneously, the majority of S. Tm turned GFP+ and displayed high fluorescence intensity. Thus, both repressors individually confine cib expression to a subset of the population. Taken together, we provide the first thorough characterization of a conventional gfp-reporter to study regulation of a group B colicin at the single cell level. This reporter will be useful to further investigate the costs and benefits of ColIb production in human pathogenic S. Tm and analyze cib expression under environmental conditions encountered in the mammalian gut. PMID:26659346

  3. Three-dimensional tissue assemblies: novel models for the study of Salmonella enterica serovar Typhimurium pathogenesis

    NASA Technical Reports Server (NTRS)

    Nickerson, C. A.; Goodwin, T. J.; Terlonge, J.; Ott, C. M.; Buchanan, K. L.; Uicker, W. C.; Emami, K.; LeBlanc, C. L.; Ramamurthy, R.; Clarke, M. S.; Vanderburg, C. R.; Hammond, T.; Pierson, D. L.

    2001-01-01

    The lack of readily available experimental systems has limited knowledge pertaining to the development of Salmonella-induced gastroenteritis and diarrheal disease in humans. We used a novel low-shear stress cell culture system developed at the National Aeronautics and Space Administration in conjunction with cultivation of three-dimensional (3-D) aggregates of human intestinal tissue to study the infectivity of Salmonella enterica serovar Typhimurium for human intestinal epithelium. Immunohistochemical characterization and microscopic analysis of 3-D aggregates of the human intestinal epithelial cell line Int-407 revealed that the 3-D cells more accurately modeled human in vivo differentiated tissues than did conventional monolayer cultures of the same cells. Results from infectivity studies showed that Salmonella established infection of the 3-D cells in a much different manner than that observed for monolayers. Following the same time course of infection with Salmonella, 3-D Int-407 cells displayed minimal loss of structural integrity compared to that of Int-407 monolayers. Furthermore, Salmonella exhibited significantly lower abilities to adhere to, invade, and induce apoptosis of 3-D Int-407 cells than it did for infected Int-407 monolayers. Analysis of cytokine expression profiles of 3-D Int-407 cells and monolayers following infection with Salmonella revealed significant differences in expression of interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-1Ra, and tumor necrosis factor alpha mRNAs between the two cultures. In addition, uninfected 3-D Int-407 cells constitutively expressed higher levels of transforming growth factor beta1 mRNA and prostaglandin E2 than did uninfected Int-407 monolayers. By more accurately modeling many aspects of human in vivo tissues, the 3-D intestinal cell model generated in this study offers a novel approach for studying microbial infectivity from the perspective of the host-pathogen interaction.

  4. Identification of Salmonella enterica Serovar Typhimurium Genes Regulated during Biofilm Formation on Cholesterol Gallstone Surfaces

    PubMed Central

    Gonzalez-Escobedo, Geoffrey

    2013-01-01

    Salmonella spp. are able to form biofilms on abiotic and biotic surfaces. In vivo studies in our laboratory have shown that Salmonella can form biofilms on the surfaces of cholesterol gallstones in the gallbladders of mice and human carriers. Biofilm formation on gallstones has been demonstrated to be a mechanism of persistence. The purpose of this work was to identify and evaluate Salmonella sp. cholesterol-dependent biofilm factors. Differential gene expression analysis between biofilms on glass or cholesterol-coated surfaces and subsequent quantitative real-time PCR (qRT-PCR) revealed that type 1 fimbria structural genes and a gene encoding a putative outer membrane protein (ycfR) were specifically upregulated in Salmonella enterica serovar Typhimurium biofilms grown on cholesterol-coated surfaces. Spatiotemporal expression of ycfR and FimA verified their regulation during biofilm development on cholesterol-coated surfaces. Surprisingly, confocal and scanning electron microscopy demonstrated that a mutant of type 1 fimbria structural genes (ΔfimAICDHF) and a ycfR mutant showed increased biofilm formation on cholesterol-coated surfaces. In vivo experiments using Nramp1+/+ mice harboring gallstones showed that only the ΔycfR mutant formed extensive biofilms on mouse gallstones at 7 and 21 days postinfection; ΔfimAICDHF was not observed on gallstone surfaces after the 7-day-postinfection time point. These data suggest that in Salmonella spp., wild-type type 1 fimbriae are important for attachment to and/or persistence on gallstones at later points of chronic infection, whereas YcfR may represent a specific potential natural inhibitor of initial biofilm formation on gallstones. PMID:23897604

  5. A regional Salmonella enterica serovar Typhimurium outbreak associated with raw beef products, The Netherlands, 2010.

    PubMed

    Friesema, Ingrid H M; Schimmer, Barbara; Ros, Jeanette A; Ober, Henk Jan; Heck, Max E O C; Swaan, Corien M; de Jager, Carolien M; Peran i Sala, Rosa M; van Pelt, Wilfrid

    2012-02-01

    Between April and May 2010, several medical microbiological laboratories in the Netherlands notified a total of 90 cases of Salmonella enterica serovar Typhimurium with the same antibiogram type (resistant for ampicillin, tetracycline, and co-trimoxazol) and the same multiple locus variable number tandem repeats analysis pattern (03-16-09-NA-311) or single locus variants. Date of illness onset ranged from end of March to mid-May with a peak in the second week of April. Almost half of the cases were hospitalized. Cases completed a questionnaire about food items and other risk factors in the 7 days before illness onset. A matched case-control study was performed. Consumption of "ossenworst" (matched odds ratio 48.2 [95% confidence interval (CI): 3.9-595.9]) and filet américain (8.5 [95% CI: 1.0-73.6]) were found to be significant risk factors for illness. Eighty percent of the cases had eaten at least one or both raw meat products. The producer of the ground beef that was used to produce the "ossenworst" was identified, but no microbiological evidence was found. Consumers should be made more aware of the presence of raw meat in ready-to-eat products and of the potential risk in eating these products. Vulnerable persons such as young children, elderly, and persons with poor health should be discouraged from eating these products. Detection of this outbreak was mainly based on the antibiogram pattern that had identified possible cases 10 days before detailed typing results from the reference laboratory became available, thus facilitating early case findings. PMID:22047057

  6. A Murine Model to Study the Antibacterial Effect of Copper on Infectivity of Salmonella Enterica Serovar Typhimurium

    PubMed Central

    Sharan, Riti; Chhibber, Sanjay; Reed, Robert H.

    2011-01-01

    This study investigated the effect of copper as an antibacterial agent on the infectivity of Salmonella enterica serovar Typhimurium. Mice were infected orally with a standardized dose of unstressed Salmonella Typhimurium and copper-stressed cells of Salmonella Typhimurium. Bacterial counts in ileum, blood, liver and spleen were observed up to 168 h under normal aerobic conditions. Serum sensitivity, phagocytosis, malondialdehyde levels and histopathology were studied for both set of animals. A decreased bacterial count in the organs with mild symptoms of infection and a complete recovery by 48 h was observed in mice infected with copper-stressed bacteria. Histopathological examination of ileum tissue demonstrated regeneration of damaged tissue post-infection with copper-stressed bacteria and no malondialdehyde levels were detected after 24 h in ileum, spleen and liver. Exposure to copper sensitized Salmonella Typhimurium to the lytic action of serum and intracellular killing by peritoneal macrophages. It can be concluded that copper stress confers a decrease in the infectivity of healthy Salmonella Typhimurium in normal mice. This study highlights the significance of use of copper as an antibacterial agent against Salmonella Typhimurium in reducing the risk of incidence of Salmonella infections from contaminated water. PMID:21318012

  7. Characterization and differential gene expression between two phenotypic phase variants in Salmonella enterica serovar Typhimurium.

    PubMed

    Patterson, Sheila K; Borewicz, Klaudyna; Johnson, Timothy; Xu, Wayne; Isaacson, Richard E

    2012-01-01

    Salmonella enterica serovar Typhimurium strain 798 has previously been shown to undergo phenotypic phase variation. One of the phenotypes expresses virulence traits such as adhesion, while the other phenotype does not. Phenotypic phase variation appears to correlate with the ability of this strain to cause persistent, asymptomatic infections of swine. A new method to detect cells in either phenotypic phase was developed using Evans Blue-Uranine agar plates. Using this new assay, rates of phenotypic phase variation were obtained. The rate of phase variation from non-adhesive to adhesive phenotype was approximately 10(-4) per cell per generation while phase variation from the adhesive to the non-adhesive phenotype was approximately 10(-6) per cell per generation. Two highly virulent S. Typhimurium strains, SL1344 and ATCC 14028, were also shown to undergo phase variation. However, while the rate from adhesive to non-adhesive phenotype was approximately the same as for strain 798, the non-adhesive to adhesive phenotype shift was 37-fold higher. Differential gene expression was measured using RNA-Seq. Eighty-three genes were more highly expressed by 798 cells in the adhesive phenotype compared to the non-adhesive cells. Most of the up-regulated genes were in virulence genes and in particular all genes in the Salmonella pathogenicity island 1 were up-regulated. When compared to the virulent strain SL1344, expression of the virulence genes was approximately equal to those up-regulated in the adhesive phenotype of strain 798. A comparison of invasive ability demonstrated that strain SL1344 was the most invasive followed by the adhesive phenotype of strain 798, then the non-adhesive phenotype of strain 798. The least invasive strain was ATCC 14028. The genome of strain 798 was sequenced and compared to SL1344. Both strains had very similar genome sequences and gene deletions could not readily explain differences in the rates of phase variation from non-adhesive to the

  8. Genomic diversity and adaptation of Salmonella enterica serovar Typhimurium from analysis of six genomes of different phage types

    PubMed Central

    2013-01-01

    Background Salmonella enterica serovar Typhimurium (or simply Typhimurium) is the most common serovar in both human infections and farm animals in Australia and many other countries. Typhimurium is a broad host range serovar but has also evolved into host-adapted variants (i.e. isolated from a particular host such as pigeons). Six Typhimurium strains of different phage types (defined by patterns of susceptibility to lysis by a set of bacteriophages) were analysed using Illumina high-throughput genome sequencing. Results Variations between strains were mainly due to single nucleotide polymorphisms (SNPs) with an average of 611 SNPs per strain, ranging from 391 SNPs to 922 SNPs. There were seven insertions/deletions (indels) involving whole or partial gene deletions, four inactivation events due to IS200 insertion and 15 pseudogenes due to early termination. Four of these inactivated or deleted genes may be virulence related. Nine prophage or prophage remnants were identified in the six strains. Gifsy-1, Gifsy-2 and the sopE2 and sspH2 phage remnants were present in all six genomes while Fels-1, Fels-2, ST64B, ST104 and CP4-57 were variably present. Four strains carried the 90-kb plasmid pSLT which contains several known virulence genes. However, two strains were found to lack the plasmid. In addition, one strain had a novel plasmid similar to Typhi strain CT18 plasmid pHCM2. Conclusion The genome data suggest that variations between strains were mainly due to accumulation of SNPs, some of which resulted in gene inactivation. Unique genetic elements that were common between host-adapted phage types were not found. This study advanced our understanding on the evolution and adaptation of Typhimurium at genomic level. PMID:24138507

  9. A proteomic approach to study Salmonella enterica serovar Typhimurium putative transporter YjeH associated with ceftriaxone resistance

    SciTech Connect

    Hu, Wensi S. Lin, Y.-H.; Shih, C.-C.

    2007-09-28

    Mutant 6B7 of Salmonella enterica serovar Typhimurium has a transposon inserted in the putative transporter gene yjeH and shows a more-than-fourfold reduction in resistance to ceftriaxone. In this report we have used proteomic analysis to compare outer membrane protein profiles between this mutant and its parental strain R200. Five identified proteins were found to be altered. Of these proteins, the level of expression of the porin OmpD was increased and those of the putative outer membrane proteins STM1530 and STM3031, a subunit of the proton-pumping oxidoreductase NuoB and the heat shock protein MopA were decreased in 6B7 strain. Although the function of the yjeH gene remains unknown, a complementation assay suggested that the OmpD, STM1530, STM3031, NuoB, and MopA proteins are associated with ceftriaxone resistance and the expression of these proteins is influenced by the putative transporter gene yjeH in S. enterica serovar Typhimurium.

  10. Osmoregulated periplasmic glucans are needed for competitive growth and biofilm formation by Salmonella enterica serovar Typhimurium in leafy-green vegetable wash-waters and colonization in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osmoregulated periplasmic glucans (OPGs) are major periplasmic constituents of Gram negative bacteria. The role of OPGs has been postulated in symbiotic as well as pathogenic host-microbe interactions. Here we report the role of OPGs from Salmonella enterica serovar Typhimurium during growth and b...

  11. Evidence for Lack of Acquisition of Tolerance in Salmonella enterica Serovar Typhimurium ATCC 14028 after Exposure to Subinhibitory Amounts of Origanum vulgare L. Essential Oil and Carvacrol

    PubMed Central

    Luz, Isabelle da Silva; Gomes Neto, Nelson Justino; Tavares, Adassa Gama; Nunes, Pollyana Campos; Magnani, Marciane

    2012-01-01

    Overnight exposure of Salmonella enterica serovar Typhimurium to sublethal amounts of Origanum vulgare essential oil (OV) and carvacrol (CAR) did not result in direct and cross-bacterial protection. Cells subcultured with increasing amounts of OV or CAR survived up to the MIC of either compound, revealing few significant changes in bacterial susceptibility. PMID:22544235

  12. Mixed biofilm formation by Shiga toxin-producing Escherichia coli and Salmonella enterica serovar typhimurium enhanced bacterial resistance to sanitization due to extracellular polymeric substances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin–producing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium are important foodborne pathogens capable of forming single-species biofilms or coexisting in multispecies biofilm communities. Bacterial biofilm cells are usually more resistant to sanitization than their pla...

  13. Phenotype microarray analysis of a Salmonella enterica serovar Typhimurium qseC mutant compared to a qseBC mutant and the wild-type strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Salmonella enterica serovar Typhimurium QseBC two-component system has previously been shown to regulate bacterial motility and colonization potential in the porcine gastrointestinal tract. A qseC mutant has decreased bacterial motility and decreased colonization in swine. However, in the absenc...

  14. Differences in Pathogenesis for Salmonella enterica serovar Typhimurium in the Mouse Versus the Swine Model Identify Bacterial Gene Products Required for Systemic but not Gastrointestinal Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last several decades, the mouse model of Typhoid fever has been an extremely productive model to investigate Salmonella enterica serovar Typhimurium pathogenesis. The mouse is the paradigm for investigating systemic disease due to infection by Salmonella; however, the swine model of gastro...

  15. Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain SO3 (Sequence Type 302) Isolated from a Baby with Meningitis in Mexico

    PubMed Central

    Puente, José L.; Calva, Edmundo; Zaidi, Mussaret B.

    2016-01-01

    The complete genome of Salmonella enterica serovar Typhimurium strain SO3 (sequence type 302), isolated from a fatal meningitis infection in Mexico, was determined using PacBio technology. The chromosome hosts six complete prophages and is predicted to harbor 51 genomic islands, including 13 pathogenicity islands (SPIs). It carries the Salmonella virulence plasmid (pSTV). PMID:27103717

  16. Complete genome sequencing of a multidrug-resistant and human-invasive Salmonella enterica serovar Typhimurium strain of the emerging sequence type 213 genotype

    SciTech Connect

    Calva, Edmundo; Silva, Claudia; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.; Vinuesa, Pablo

    2015-06-18

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids.

  17. Genome and Transcriptome Adaptation Accompanying Emergence of the Definitive Type 2 Host-Restricted Salmonella enterica Serovar Typhimurium Pathovar

    PubMed Central

    Kingsley, Robert A.; Kay, Sally; Connor, Thomas; Barquist, Lars; Sait, Leanne; Holt, Kathryn E.; Sivaraman, Karthi; Wileman, Thomas; Goulding, David; Clare, Simon; Hale, Christine; Seshasayee, Aswin; Harris, Simon; Thomson, Nicholas R.; Gardner, Paul; Rabsch, Wolfgang; Wigley, Paul; Humphrey, Tom; Parkhill, Julian; Dougan, Gordon

    2013-01-01

    ABSTRACT Salmonella enterica serovar Typhimurium definitive type 2 (DT2) is host restricted to Columba livia (rock or feral pigeon) but is also closely related to S. Typhimurium isolates that circulate in livestock and cause a zoonosis characterized by gastroenteritis in humans. DT2 isolates formed a distinct phylogenetic cluster within S. Typhimurium based on whole-genome-sequence polymorphisms. Comparative genome analysis of DT2 94-213 and S. Typhimurium SL1344, DT104, and D23580 identified few differences in gene content with the exception of variations within prophages. However, DT2 94-213 harbored 22 pseudogenes that were intact in other closely related S. Typhimurium strains. We report a novel in silico approach to identify single amino acid substitutions in proteins that have a high probability of a functional impact. One polymorphism identified using this method, a single-residue deletion in the Tar protein, abrogated chemotaxis to aspartate in vitro. DT2 94-213 also exhibited an altered transcriptional profile in response to culture at 42°C compared to that of SL1344. Such differentially regulated genes included a number involved in flagellum biosynthesis and motility. PMID:23982073

  18. Gold nanoparticle-DNA aptamer conjugate-assisted delivery of antimicrobial peptide effectively eliminates intracellular Salmonella enterica serovar Typhimurium.

    PubMed

    Yeom, Ji-Hyun; Lee, Boeun; Kim, Daeyoung; Lee, Jong-Kook; Kim, Suk; Bae, Jeehyeon; Park, Yoonkyung; Lee, Kangseok

    2016-10-01

    Antimicrobial peptides (AMPs) are a promising new class of antibacterial compounds. However, their applications in the treatment of intracellular pathogenic bacteria have been limited by their in vivo instability and low penetrating ability into mammalian cells. Here, we report that gold nanoparticles conjugated with DNA aptamer (AuNP-Apt) efficiently delivered AMPs into mammalian living systems with enhanced stability of the AMPs. C-terminally hexahistidine-tagged A3-APO (A3-APO(His)) AMPs were loaded onto AuNPs conjugated with His-tag DNA aptamer (AuNP-Apt(His)) by simple mixing and were delivered into Salmonella enterica serovar Typhimurium (S. Typhimurium)-infected HeLa cells, resulting in the increased viability of host cells due to the elimination of intracellular S. Typhimurium cells. Furthermore, the intravenous injection of AuNP-Apt(His) loaded with A3-APO(His) into S. Typhimurium-infected mice resulted in a complete inhibition of S. Typhimurium colonization in the mice organs, leading to 100% survival of the mice. Therefore, AuNP-Apt(His) can serve as an innovative platform for AMP therapeutics to treat intracellular bacterial infections in mammals. PMID:27424215

  19. Higher Storage Temperature Causes Greater Salmonella enterica Serovar Typhimurium Internal Penetration of Artificially Contaminated, Commercially Available, Washed Free Range Eggs.

    PubMed

    Whiley, Alice; Fallowfield, Howard; Ross, Kirstin; McEvoy, Vanessa; Whiley, Harriet

    2016-07-01

    Foodborne salmonellosis is a major public health concern, with contaminated eggs identified as a significant source of infection. In Australia, the most prevalent cause of salmonellosis from eggs is Salmonella enterica subsp. enterica serovar Typhimurium. This study explored the effect of temperature after 1, 7, 14, 21, and 28 days of storage on commercially available washed free range eggs, artificially contaminated with Salmonella Typhimurium on the external surface. At each time point, the external surface of the egg, the crushed eggshell, and the internal egg yolk and albumen were analyzed for Salmonella. After 28 days of storage, 25% of eggs stored at 4°C, 50% of eggs stored at 14°C, and 100% of eggs stored at 23 and 35°C were internally contaminated with Salmonella. After 1 day of storage, more than 50% of all eggs had Salmonella present in the crushed shell after the external surface had been disinfected with ethanol. This is the first study to demonstrate that refrigeration reduced the potential for Salmonella Typhimurium to penetrate the eggshell membrane and internally contaminate table eggs commercially available in Australia. It also suggests that the processes of cracking eggs may be a source of cross-contamination within the kitchen. PMID:27357046

  20. Differences in Salmonella enterica serovar Typhimurium strain invasiveness are associated with heterogeneity in SPI-1 gene expression

    PubMed Central

    Clark, Leann; Perrett, Charlotte A.; Malt, Layla; Harward, Caryn; Humphrey, Suzanne; Jepson, Katy A.; Martinez-Argudo, Isabel; Carney, Laura J.; La Ragione, Roberto M.; Humphrey, Tom J.

    2011-01-01

    Most studies on Salmonella enterica serovar Typhimurium infection focus on strains ATCC SL1344 or NTCC 12023 (ATCC 14028). We have compared the abilities of these strains to induce membrane ruffles and invade epithelial cells. S. Typhimurium strain 12023 is less invasive and induces smaller membrane ruffles on MDCK cells compared with SL1344. Since the SPI-1 effector SopE is present in SL1344 and absent from 12023, and SL1344 sopE mutants have reduced invasiveness, we investigated whether 12023 is less invasive due to the absence of SopE. However, comparison of SopE+ and SopE− S. Typhimurium strains, sopE deletion mutants and 12023 expressing a sopE plasmid revealed no consistent relationship between SopE status and relative invasiveness. Nevertheless, absence of SopE was closely correlated with reduced size of membrane ruffles. A PprgH–gfp reporter revealed that relatively few of the 12023 population (and that of the equivalent strain ATCC 14028) express SPI-1 compared to other S. Typhimurium strains. Expression of a PhilA–gfp reporter mirrored that of PprgH–gfp in 12023 and SL1344, implicating reduced signalling via the transcription factor HilA in the heterogeneous SPI-1 expression of these strains. The previously unrecognized strain heterogeneity in SPI-1 expression and invasiveness has important implications for studies of Salmonella infection. PMID:21493681

  1. Induction of the carrier state in pigeons infected with Salmonella enterica subspecies enterica serovar typhimurium PT99 by treatment with florfenicol: a matter of pharmacokinetics.

    PubMed

    Pasmans, Frank; Baert, Kris; Martel, An; Bousquet-Melou, Alain; Lanckriet, Ruben; De Boever, Sandra; Van Immerseel, Filip; Eeckhaut, Venessa; de Backer, Patrick; Haesebrouck, Freddy

    2008-03-01

    Paratyphoid caused by Salmonella enterica subsp. enterica serovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonella serovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonella infection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonella strain used (4 microg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 microg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonella serovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonella shedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency. PMID:18180355

  2. Induction of the Carrier State in Pigeons Infected with Salmonella enterica Subspecies enterica Serovar Typhimurium PT99 by Treatment with Florfenicol: a Matter of Pharmacokinetics▿

    PubMed Central

    Pasmans, Frank; Baert, Kris; Martel, An; Bousquet-Melou, Alain; Lanckriet, Ruben; De Boever, Sandra; Van Immerseel, Filip; Eeckhaut, Venessa; de Backer, Patrick; Haesebrouck, Freddy

    2008-01-01

    Paratyphoid caused by Salmonella enterica subsp. enterica serovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonella serovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonella infection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonella strain used (4 μg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 μg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonella serovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonella shedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency. PMID:18180355

  3. The Periplasmic Nitrate Reductase NapABC Supports Luminal Growth of Salmonella enterica Serovar Typhimurium during Colitis

    PubMed Central

    Lopez, Christopher A.; Rivera-Chávez, Fabian; Byndloss, Mariana X.

    2015-01-01

    The food-borne pathogen Salmonella enterica serovar Typhimurium benefits from acute inflammation in part by using host-derived nitrate to respire anaerobically and compete successfully with the commensal microbes during growth in the intestinal lumen. The S. Typhimurium genome contains three nitrate reductases, encoded by the narGHI, narZYV, and napABC genes. Work on homologous genes present in Escherichia coli suggests that nitrate reductase A, encoded by the narGHI genes, is the main enzyme promoting growth on nitrate as an electron acceptor in anaerobic environments. Using a mouse colitis model, we found, surprisingly, that S. Typhimurium strains with defects in either nitrate reductase A (narG mutant) or the regulator inducing its transcription in the presence of high concentrations of nitrate (narL mutant) exhibited growth comparable to that of wild-type S. Typhimurium. In contrast, a strain lacking a functional periplasmic nitrate reductase (napA mutant) exhibited a marked growth defect in the lumen of the colon. In E. coli, the napABC genes are transcribed maximally under anaerobic growth conditions in the presence of low nitrate concentrations. Inactivation of narP, encoding a response regulator that activates napABC transcription in response to low nitrate concentrations, significantly reduced the growth of S. Typhimurium in the gut lumen. Cecal nitrate measurements suggested that the murine cecum is a nitrate-limited environment. Collectively, our results suggest that S. Typhimurium uses the periplasmic nitrate reductase to support its growth on the low nitrate concentrations encountered in the gut, a strategy that may be shared with other enteric pathogens. PMID:26099579

  4. Crl Activates Transcription Initiation of RpoS-Regulated Genes Involved in the Multicellular Behavior of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Robbe-Saule, Véronique; Jaumouillé, Valentin; Prévost, Marie-Christine; Guadagnini, Stéphanie; Talhouarne, Christelle; Mathout, Hayette; Kolb, Annie; Norel, Françoise

    2006-01-01

    In Salmonella enterica serovar Typhimurium, the stationary-phase sigma factor σS (RpoS) is required for virulence, stress resistance, biofilm formation, and development of the rdar morphotype. This morphotype is a multicellular behavior characterized by expression of the adhesive extracellular matrix components cellulose and curli fimbriae. The Crl protein of Escherichia coli interacts with σS and activates expression of σS-regulated genes, such as the csgBAC operon encoding the subunit of the curli proteins, by an unknown mechanism. Here, we showed using in vivo and in vitro experiments that the Crl protein of Salmonella serovar Typhimurium is required for development of a typical rdar morphotype and for maximal expression of the csgD, csgB, adrA, and bcsA genes, which are involved in curli and cellulose biosynthesis. In vitro transcription assays and potassium permanganate reactivity experiments with purified His6-Crl showed that Crl directly activated σS-dependent transcription initiation at the csgD and adrA promoters. We observed no effect of Crl on σ70-dependent transcription. Crl protein levels increased during the late exponential and stationary growth phases in Luria-Beratani medium without NaCl at 28°C. We obtained complementation of the crl mutation by increasing σS levels. This suggests that Crl has a major physiological impact at low concentrations of σS. PMID:16707690

  5. Coordinated Regulation of Two Independent Cell-Cell Signaling Systems and Swarmer Differentiation in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Kim, Wook; Surette, Michael G.

    2006-01-01

    Almost all members of the genus Salmonella differentiate and migrate on semisolid surfaces in a coordinated population behavior known as swarming. Important virulence determinants are coupled to swarmer differentiation in several other pathogenic organisms, collectively suggesting that conditions that trigger swarming in the laboratory may fortuitously promote the cells to enter a robust physiological state relevant to the host environment. Here, we present evidence that expression of two independent cell-cell signaling systems are also coupled to swarmer differentiation in S. enterica serovar Typhimurium. Expression of both pfs and sdiA genes was up-regulated in the actively migrating swarmers compared to their vegetative counterparts propagated in broth or spread plated on the surface of swim, swarm, and solid media. Accordingly, swarmers produced elevated levels of a universally recognized signaling molecule, autoinducer-2, and exhibited increased sensitivity to N-acyl homoserine lactones (AHLs), signaling molecules that Salmonella does not produce. Expression of the rck operon was concomitantly up-regulated in the swarmers in an SdiA-dependent manner only in the presence of exogenous AHLs. In addition to the previously reported adaptive antibiotic resistance phenotype and global shift in metabolism, this work presents another component of the physiological changes that are specifically associated with swarmer differentiation in serovar Typhimurium and not simply due to growth on a surface. PMID:16385032

  6. Complete Nucleotide Sequences of Virulence-Resistance Plasmids Carried by Emerging Multidrug-Resistant Salmonella enterica Serovar Typhimurium Isolated from Cattle in Hokkaido, Japan

    PubMed Central

    Tamamura, Yukino; Tanaka, Kiyoshi; Akiba, Masato; Kanno, Toru; Hatama, Shinichi; Ishihara, Ryoko; Uchida, Ikuo

    2013-01-01

    In the present study, we have shown that virulence-resistance plasmids from emerging multidrug-resistant isolates of Salmonella enterica serovar Typhimurium were derived from a virulence-associated plasmid, essential for systematic invasiveness of S. Typhimurium in mice (pSLT), through acquisition of a large insert containing a resistance island flanked by IS1294 elements. A blaCMY-2-carrying plasmid from a cefotaxime-resistant isolate comprised a segment of Escherichia coli plasmid pAR060302 and the replication region (IncFIB) of a virulence-resistance plasmid. These results provide insights into the evolution of drug resistance in emerging clones of S. Typhimurium. PMID:24155970

  7. No Beneficial Effects Evident for Enterococcus faecium NCIMB 10415 in Weaned Pigs Infected with Salmonella enterica Serovar Typhimurium DT104

    PubMed Central

    Kreuzer, Susanne; Aßmus, Jens; Schmidt, Michael F. G.; Brockmann, Gudrun A.; Nöckler, Karsten

    2012-01-01

    Salmonella enterica serovar Typhimurium DT 104 is the major pathogen for salmonellosis outbreaks in Europe. We tested if the probiotic bacterium Enterococcus faecium NCIMB 10415 can prevent or alleviate salmonellosis. Therefore, piglets of the German Landrace breed that were treated with E. faecium (n = 16) as a feed additive and untreated controls (n = 16) were challenged with S. Typhimurium 10 days after weaning. The presence of salmonellae in feces and selected organs, as well as the immune response, were investigated. Piglets treated with E. faecium gained less weight than control piglets (P = 0.05). The feeding of E. faecium had no effect on the fecal shedding of salmonellae and resulted in a higher abundance of the pathogen in tonsils of all challenged animals. The specific (anti-Salmonella IgG) and nonspecific (haptoglobin) humoral immune responses as well as the cellular immune response (T helper cells, cytotoxic T cells, regulatory T cells, γδ T cells, and B cells) in the lymph nodes, Peyer's patches of different segments of the intestine (jejunal and ileocecal), the ileal papilla, and in the blood were affected in the course of time after infection (P < 0.05) but not by the E. faecium treatment. These results led to the conclusion that E. faecium may not have beneficial effects on the performance of weaned piglets in the case of S. Typhimurium infection. Therefore, we suggest a critical discussion and reconsideration of E. faecium NCIMB 10415 administration as a probiotic for pigs. PMID:22544257

  8. Salmonella enterica serovar Typhimurium strain lacking pmrG-HM-D provides excellent protection against salmonellosis in murine typhoid model.

    PubMed

    Negi, Vidya Devi; Singhamahapatra, Santanu; Chakravortty, Dipshikha

    2007-07-20

    The superiority of live attenuated vaccines in systemic salmonellosis has been proven over killed and subunit vaccines, because of its ability to induce protective cell mediated immunity by CD8+ T cells. A live attenuated Salmonella enterica serovar Typhimurium vaccine has been developed by systematic site directed deletion of the pmrG-HM-D chromosomal genomic loci. This gene confers involved in antimicrobial peptide resistance and is involved in LPS modification, both of which are the major immune evasive mechanisms in Salmonella. The efficacy of the newly developed strain in inducing protection against mortality after challenge with the virulent wild type Salmonella typhimurium 12023 was evaluated in mice model of typhoid fever. Animals were immunized and then boosted on days 7 and 14. Following challenge with virulent S. typhimurium 12023, organ burden and mortality of vaccinated mice were less compared to non-immunized controls. The vaccine strain also induced elevated CD8+ T cells in the vaccinated mice. This multiple mutant vaccine candidate appears to be safe for use in pregnant mice and provides a model for the development of live vaccine candidates against naturally occurring salmonellosis and typhoid fever. PMID:17574312

  9. Contribution of Proton-Translocating Proteins to the Virulence of Salmonella enterica Serovars Typhimurium, Gallinarum, and Dublin in Chickens and Mice

    PubMed Central

    Turner, A. K.; Barber, L. Z.; Wigley, P.; Muhammad, S.; Jones, M. A.; Lovell, M. A.; Hulme, S.; Barrow, P. A.

    2003-01-01

    We investigated the attenuating effects of a range of respiratory chain mutations in three Salmonella serovars which might be used in the development of live vaccines. We tested mutations in nuoG, cydA, cyoA, atpB, and atpH in three serovars of Salmonella enterica: Typhimurium, Dublin, and Gallinarum. All three serovars were assessed for attenuation in their relevant virulence assays of typhoid-like infections. Serovar Typhimurium was assessed in 1-day-old chickens and the mouse. Serovar Gallinarum 9 was assessed in 3-week-old chickens, and serovar Dublin was assessed in 6-week-old mice. Our data show variation in attenuation for the nuoG, cydA, and cyoA mutations within the different serovar-host combinations. However, mutations in atpB and atpH were highly attenuating for all three serovars in the various virulence assays. Further investigation of the mutations in the atp operon showed that the bacteria were less invasive in vivo, showing reduced in vitro survival within phagocytic cells and reduced acid tolerance. We present data showing that this reduced acid tolerance is due to an inability to adapt to conditions rather than a general sensitivity to reduced pH. The data support the targeting of respiratory components for the production of live vaccines and suggest that mutations in the atp operon provide suitable candidates for broad-spectrum attenuation of a range of Salmonella serovars. PMID:12761123

  10. Molecular Profiling: Catecholamine Modulation of Gene Expression in Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium.

    PubMed

    Bearson, Bradley L

    2016-01-01

    Investigations of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various phenotypes. For example, one of the most intensively investigated phenotypes following exposure of E. coli and S. Typhimurium to norepinephrine is enhanced bacterial growth in a serum-based medium. Host-pathogen investigations have demonstrated that the mammalian host utilizes nutritional immunity to sequester iron and prevent extraintestinal growth by bacterial pathogens. However, Salmonella and certain E. coli strains have a genetic arsenal designed for subversion and subterfuge of the host. Norepinephrine enhances bacterial growth due, in part, to increased iron availability, and transcriptional profiling indicates differential expression of genes encoding iron acquisition and transport proteins. Bacterial motility of E. coli and S. Typhimurium is also enhanced in the presence of catecholamines and increased flagellar gene expression has been described. Furthermore, epinephrine and norepinephrine are chemoattractants for E. coli O157:H7. In S. Typhimurium, norepinephrine enhances horizontal gene transfer and increases expression of genes involved in plasmid transfer. Exposure of E. coli O157:H7 to norepinephrine increases expression of the genes encoding Shiga toxin and operons within the locus of enterocyte effacement (LEE). Alterations in the transcriptional response of enteric bacteria to catecholamine exposure in vivo are predicted to enhance bacterial colonization and pathogen virulence. This chapter will review the current literature on the transcriptional response of E. coli and S. Typhimurium to catecholamines. PMID:26589218

  11. Novel small RNA (sRNA) landscape of the starvation-stress response transcriptome of Salmonella enterica serovar typhimurium.

    PubMed

    Amin, Shivam V; Roberts, Justin T; Patterson, Dillon G; Coley, Alexander B; Allred, Jonathan A; Denner, Jason M; Johnson, Justin P; Mullen, Genevieve E; O'Neal, Trenton K; Smith, Jason T; Cardin, Sara E; Carr, Hank T; Carr, Stacie L; Cowart, Holly E; DaCosta, David H; Herring, Brendon R; King, Valeria M; Polska, Caroline J; Ward, Erin E; Wise, Alice A; McAllister, Kathleen N; Chevalier, David; Spector, Michael P; Borchert, Glen M

    2016-03-01

    Small RNAs (sRNAs) are short (∼50-200 nucleotides) noncoding RNAs that regulate cellular activities across bacteria. Salmonella enterica starved of a carbon-energy (C) source experience a host of genetic and physiological changes broadly referred to as the starvation-stress response (SSR). In an attempt to identify novel sRNAs contributing to SSR control, we grew log-phase, 5-h C-starved and 24-h C-starved cultures of the virulent Salmonella enterica subspecies enterica serovar Typhimurium strain SL1344 and comprehensively sequenced their small RNA transcriptomes. Strikingly, after employing a novel strategy for sRNA discovery based on identifying dynamic transcripts arising from "gene-empty" regions, we identify 58 wholly undescribed Salmonella sRNA genes potentially regulating SSR averaging an ∼1,000-fold change in expression between log-phase and C-starved cells. Importantly, the expressions of individual sRNA loci were confirmed by both comprehensive transcriptome analyses and northern blotting of select candidates. Of note, we find 43 candidate sRNAs share significant sequence identity to characterized sRNAs in other bacteria, and ∼70% of our sRNAs likely assume characteristic sRNA structural conformations. In addition, we find 53 of our 58 candidate sRNAs either overlap neighboring mRNA loci or share significant sequence complementarity to mRNAs transcribed elsewhere in the SL1344 genome strongly suggesting they regulate the expression of transcripts via antisense base-pairing. Finally, in addition to this work resulting in the identification of 58 entirely novel Salmonella enterica genes likely participating in the SSR, we also find evidence suggesting that sRNAs are significantly more prevalent than currently appreciated and that Salmonella sRNAs may actually number in the thousands. PMID:26853797

  12. Iron-Induced Virulence of Salmonella enterica Serovar Typhimurium at the Intestinal Epithelial Interface Can Be Suppressed by Carvacrol

    PubMed Central

    Kortman, Guus A. M.; Roelofs, Rian W. H. M.; Swinkels, Dorine W.; de Jonge, Marien I.; Burt, Sara A.

    2014-01-01

    Oral iron therapy can increase the abundance of bacterial pathogens, e.g., Salmonella spp., in the large intestine of African children. Carvacrol is a natural compound with antimicrobial activity against various intestinal bacterial pathogens, among which is the highly prevalent Salmonella enterica serovar Typhimurium. This study aimed to explore a presumed interaction between carvacrol and bacterial iron handling and to assess the potential of carvacrol in preventing the increase of bacterial pathogenicity during high iron availability. S. Typhimurium was cultured with increasing concentrations of iron and carvacrol to study the effects of these combined interventions on growth, adhesion to intestinal epithelial cells, and iron uptake/influx in both bacterial and epithelial cells. In addition, the ability of carvacrol to remove iron from the high-affinity ligand transferrin and an Fe-dye complex was examined. Carvacrol retarded growth of S. Typhimurium at all iron conditions. Furthermore, iron-induced epithelial adhesion was effectively reduced by carvacrol at high iron concentrations. The reduction of growth and virulence by carvacrol was not paralleled by a change in iron uptake or influx into S. Typhimurium. In contrast, bioavailability of iron for epithelial cells was moderately decreased under these conditions. Further, carvacrol was shown to lack the properties of an iron binding molecule; however, it was able to weaken iron-ligand interactions by which it may possibly interfere with bacterial virulence. In conclusion, our in vitro data suggest that carvacrol has the potential to serve as a novel dietary supplement to prevent pathogenic overgrowth and colonization in the large intestine during oral iron therapy. PMID:24379194

  13. The Small RNA DsrA Influences the Acid Tolerance Response and Virulence of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Ryan, Daniel; Ojha, Urmesh K.; Jaiswal, Sangeeta; Padhi, Chandrashekhar; Suar, Mrutyunjay

    2016-01-01

    The Gram-negative, enteropathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) is exposed to various stress conditions during pathogenesis, of which acid stress serves as a major defense mechanism in the host. Such environments are encountered in the stomach and Salmonella containing vacuole of phagocytic and non-phagocytic cells. It is only recently that small RNAs (sRNAs) have come to the forefront as major regulators of stress response networks. Consequently, the sRNA DsrA which regulates acid resistance in Escherichia coli, has not been characterized in the acid tolerance response (ATR) of Salmonella. In this study, we show dsrA to be induced two and threefold under adaptation and challenge phases of the ATR, respectively. Additionally, an isogenic mutant lacking dsrA (ΔDsrA) displayed lower viability under the ATR along with reduced motility, feeble adhesion and defective invasion efficacy in vitro. Expression analysis revealed down regulation of several Salmonella pathogenicity island-1 (SPI-1) effectors in ΔDsrA compared to the wild-type, under SPI-1 inducing conditions. Additionally, our in vivo data revealed ΔDsrA to be unable to cause gut inflammation in C57BL/6 mice at 72 h post infection, although intracellular survival and systemic dissemination remained unaffected. A possible explanation may be the significantly reduced expression of flagellin structural genes fliC and fljB in ΔDsrA, which have been implicated as major proinflammatory determinants. This study serves to highlight the role of sRNAs such as DsrA in both acid tolerance and virulence of S. Typhimurium. Additionally the robust phenotype of non-invasiveness could be exploited in developing SPI-I attenuated S. Typhimurium strains without disrupting SPI-I genes. PMID:27199929

  14. Live and inactivated Salmonella enterica serovar Typhimurium stimulate similar but distinct transcriptome profiles in bovine macrophages and dendritic cells.

    PubMed

    Jensen, Kirsty; Gallagher, Iain J; Kaliszewska, Anna; Zhang, Chen; Abejide, Oluyinka; Gallagher, Maurice P; Werling, Dirk; Glass, Elizabeth J

    2016-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major cause of gastroenteritis in cattle and humans. Dendritic cells (DC) and macrophages (Mø) are major players in early immunity to Salmonella, and their response could influence the course of infection. Therefore, the global transcriptional response of bovine monocyte-derived DC and Mø to stimulation with live and inactivated S. Typhimurium was compared. Both cell types mount a major response 2 h post infection, with a core common response conserved across cell-type and stimuli. However, three of the most affected pathways; inflammatory response, regulation of transcription and regulation of programmed cell death, exhibited cell-type and stimuli-specific differences. The expression of a subset of genes associated with these pathways was investigated further. The inflammatory response was greater in Mø than DC, in the number of genes and the enhanced expression of common genes, e.g., interleukin (IL) 1B and IL6, while the opposite pattern was observed with interferon gamma. Furthermore, a large proportion of the investigated genes exhibited stimuli-specific differential expression, e.g., Mediterranean fever. Two-thirds of the investigated transcription factors were significantly differentially expressed in response to live and inactivated Salmonella. Therefore the transcriptional responses of bovine DC and Mø during early S. Typhimurium infection are similar but distinct, potentially due to the overall function of these cell-types. The differences in response of the host cell will influence down-stream events, thus impacting on the subsequent immune response generated during the course of the infection. PMID:27000047

  15. Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain SO2 (Sequence Type 302) Isolated from an Asymptomatic Child in Mexico

    PubMed Central

    Calva, Edmundo; Puente, José L.; Zaidi, Mussaret B.

    2016-01-01

    The complete genome sequence of Salmonella enterica serovar Typhimurium strain SO2, isolated from an asymptomatic child in Mexico, was determined using PacBio single-molecule real-time technology. Strain SO2 has six complete chromosomal prophages, namely, ST104, Gifsy-2, ST64B, Gifsy-1, ELPhiS, and FSL SP-004, and carries a Salmonella virulence plasmid. PMID:27081133

  16. Influence of rpoS mutations on the response of Salmonella enterica serovar Typhimurium to solar radiation.

    PubMed

    Oppezzo, Oscar J; Costa, Cristina S; Pizarro, Ramón A

    2011-01-10

    Salmonella enterica serovar Typhimurium is an important pathogen, and exhibits considerable resistance to the lethal effects of solar radiation. To evaluate the involvement of the RpoS transcription factor in the defense mechanisms of this organism, the sunlight response of a wild type strain (ATCC14028) was compared with that of an rpoS mutant, which exhibited increased sensitivity. Kinetics of cell death was complex in both strains, probably due to the presence of a variety of targets for the radiation. When ultraviolet radiation was excluded from the incident sunlight, lethal effects were abolished independently of the allelic state of rpoS. Reduction of oxygen concentration in the irradiation medium provided moderate protection to ATCC14028, but notably improved survival of the mutant. Similar assays were developed with another S. enterica strain (DA1468), which is a derivative of strain LT2 and produces low levels of RpoS. In this strain the loss of viability reveals the dependence on solar ultraviolet and oxygen concentration found for ATCC14028, but radiation resistance was slightly reduced. Increased sensitivity was observed in an rpoS mutant derived from DA1468, indicating that RpoS functions related to photoprotection are conserved in this strain. In addition, notable differences in the shape of the survival curves obtained for mutants derived from ATCC14028 and DA1468 were found, suggesting that genes beyond RpoS control are relevant in the sunlight response of these mutants. PMID:20875749

  17. Salmonella enterica serovar Typhimurium utilizes the ClpPX and Lon proteases for optimal fitness in the ceca of chickens.

    PubMed

    Troxell, Bryan

    2016-07-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a leading cause of salmonellosis. Poultry and poultry products are implicated in transmission of Salmonella to humans. In 2013, an outbreak of S Typhimurium occurred that comprised 39 states within the United States and was associated with backyard flocks of chickens. Colonization of the avian host by S Typhimurium requires numerous genetic factors encoded within the bacterium. Of particular interest are genetic factors induced by alternative sigma factors within S Typhimurium since these genetic elements are important for adaptation to different environmental stresses. The heat shock response is a dedicated change in gene regulation within bacteria in response to several stresses, specifically growth at 42°C. Because chickens have a higher body temperature than other animals (42°C) the hypothesis was tested that components of the heat shock response are important for optimal fitness within the chicken. To this end, deletion of the heat shock proteases clpPX (BTNC0022) or lon (BTNC0021) was accomplished and the bacterial fitness in vivo was compared to the "wild-type" strain (NC1040) using a competition assay. One-day-old chicks were orally gavaged with an equal mixture of NC1040 and either BTNC0022 or BTNC0021. Quantification of viable bacteria over time by using plate counts indicated that deletion of either heat shock protease resulted in significantly reduced colonization of the chicken ceca compared to the wild-type strain. To satisfy the molecular Koch's postulates, clpPX and lon mutants were complemented in trans using a low-copy number plasmid for additional in vivo experiments. Complementation studies confirmed the importance of either heat shock protease to colonization of the chicken ceca. This report demonstrated that both ClpPX and Lon were important for optimal fitness within chickens. Moreover, these results suggested that components of the heat shock may be critical factors used by S

  18. Salmonella enterica serovar Typhimurium utilizes the ClpPX and Lon proteases for optimal fitness in the ceca of chickens

    PubMed Central

    Troxell, Bryan

    2016-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a leading cause of salmonellosis. Poultry and poultry products are implicated in transmission of Salmonella to humans. In 2013, an outbreak of S. Typhimurium occurred that comprised 39 states within the United States and was associated with backyard flocks of chickens. Colonization of the avian host by S. Typhimurium requires numerous genetic factors encoded within the bacterium. Of particular interest are genetic factors induced by alternative sigma factors within S. Typhimurium since these genetic elements are important for adaptation to different environmental stresses. The heat shock response is a dedicated change in gene regulation within bacteria in response to several stresses, specifically growth at 42°C. Because chickens have a higher body temperature than other animals (42°C) the hypothesis was tested that components of the heat shock response are important for optimal fitness within the chicken. To this end, deletion of the heat shock proteases clpPX (BTNC0022) or lon (BTNC0021) was accomplished and the bacterial fitness in vivo was compared to the “wild-type” strain (NC1040) using a competition assay. One-day-old chicks were orally gavaged with an equal mixture of NC1040 and either BTNC0022 or BTNC0021. Quantification of viable bacteria over time by using plate counts indicated that deletion of either heat shock protease resulted in significantly reduced colonization of the chicken ceca compared to the wild-type strain. To satisfy the molecular Koch's postulates, clpPX and lon mutants were complemented in trans using a low-copy number plasmid for additional in vivo experiments. Complementation studies confirmed the importance of either heat shock protease to colonization of the chicken ceca. This report demonstrated that both ClpPX and Lon were important for optimal fitness within chickens. Moreover, these results suggested that components of the heat shock may be critical factors used

  19. Prophage sequences defining hot spots of genome variation in Salmonella enterica serovar Typhimurium can be used to discriminate between field isolates.

    PubMed

    Cooke, Fiona J; Wain, John; Fookes, Maria; Ivens, Alasdair; Thomson, Nicholas; Brown, Derek J; Threlfall, E John; Gunn, George; Foster, Geoffrey; Dougan, Gordon

    2007-08-01

    Sixty-one Salmonella enterica serovar Typhimurium isolates of animal and human origin, matched by phage type, antimicrobial resistance pattern, and place of isolation, were analyzed by microbiological and molecular techniques, including pulsed-field gel electrophoresis (PFGE) and plasmid profiling. PFGE identified 10 profiles that clustered by phage type and antibiotic resistance pattern with human and animal isolates distributed among different PFGE profiles. Genomic DNA was purified from 23 representative strains and hybridized to the composite Salmonella DNA microarray, and specific genomic regions that exhibited significant variation between isolates were identified. Bioinformatic analysis showed that variable regions of DNA were associated with prophage-like elements. Subsequently, simple multiplex PCR assays were designed on the basis of these variable regions that could be used to discriminate between S. enterica serovar Typhimurium isolates from the same geographical region. These multiplex PCR assays, based on prophage-like elements and Salmonella genomic island 1, provide a simple method for identifying new variants of S. enterica serovar Typhimurium in the field. PMID:17522270

  20. Prophage Sequences Defining Hot Spots of Genome Variation in Salmonella enterica Serovar Typhimurium Can Be Used To Discriminate between Field Isolates▿

    PubMed Central

    Cooke, Fiona J.; Wain, John; Fookes, Maria; Ivens, Alasdair; Thomson, Nicholas; Brown, Derek J.; Threlfall, E. John; Gunn, George; Foster, Geoffrey; Dougan, Gordon

    2007-01-01

    Sixty-one Salmonella enterica serovar Typhimurium isolates of animal and human origin, matched by phage type, antimicrobial resistance pattern, and place of isolation, were analyzed by microbiological and molecular techniques, including pulsed-field gel electrophoresis (PFGE) and plasmid profiling. PFGE identified 10 profiles that clustered by phage type and antibiotic resistance pattern with human and animal isolates distributed among different PFGE profiles. Genomic DNA was purified from 23 representative strains and hybridized to the composite Salmonella DNA microarray, and specific genomic regions that exhibited significant variation between isolates were identified. Bioinformatic analysis showed that variable regions of DNA were associated with prophage-like elements. Subsequently, simple multiplex PCR assays were designed on the basis of these variable regions that could be used to discriminate between S. enterica serovar Typhimurium isolates from the same geographical region. These multiplex PCR assays, based on prophage-like elements and Salmonella genomic island 1, provide a simple method for identifying new variants of S. enterica serovar Typhimurium in the field. PMID:17522270

  1. Organically managed soils reduce internal colonization of tomato plants by Salmonella enterica serovar Typhimurium.

    PubMed

    Gu, Ganyu; Cevallos-Cevallos, Juan M; Vallad, Gary E; van Bruggen, Ariena H C

    2013-04-01

    A two-phase experiment was conducted twice to investigate the effects of soil management on movement of Salmonella enterica Typhimurium in tomato plants. In the first phase, individual leaflets of 84 tomato plants grown in conventional or organic soils were dip inoculated two to four times before fruiting with either of two Salmonella Typhimurium strains (10(9) CFU/ml; 0.025% [vol/vol] Silwet L-77). Inoculated and adjacent leaflets were tested for Salmonella spp. densities for 30 days after each inoculation. Endophytic bacterial communities were characterized by polymerase chain reaction denaturing gradient gel electrophoresis before and after inoculation. Fruit and seed were examined for Salmonella spp. incidence. In phase 2, extracted seed were planted in conventional soil, and contamination of leaves and fruit of the second generation was checked. More Salmonella spp. survived in inoculated leaves on plants grown in conventional than in organic soil. The soil management effect on Salmonella spp. survival was confirmed for tomato plants grown in two additional pairs of soils. Endophytic bacterial diversities of tomato plants grown in conventional soils were significantly lower than those in organic soils. All contaminated fruit (1%) were from tomato plants grown in conventional soil. Approximately 5% of the seed from infested fruit were internally contaminated. No Salmonella sp. was detected in plants grown from contaminated seed. PMID:23506364

  2. ProP is required for the survival of desiccated Salmonella enterica serovar typhimurium cells on a stainless steel surface.

    PubMed

    Finn, Sarah; Händler, Kristian; Condell, Orla; Colgan, Aoife; Cooney, Shane; McClure, Peter; Amézquita, Aléjandro; Hinton, Jay C D; Fanning, Séamus

    2013-07-01

    Consumers trust commercial food production to be safe, and it is important to strive to improve food safety at every level. Several outbreaks of food-borne disease have been caused by Salmonella strains associated with dried food. Currently we do not know the mechanisms used by Salmonella enterica serovar Typhimurium to survive in desiccated environments. The aim of this study was to discover the responses of S. Typhimurium ST4/74 at the transcriptional level to desiccation on a stainless steel surface and to subsequent rehydration. Bacterial cells were dried onto the same steel surfaces used during the production of dry foods, and RNA was recovered for transcriptomic analysis. Subsequently, dried cells were rehydrated and were again used for transcriptomic analysis. A total of 266 genes were differentially expressed under desiccation stress compared with a static broth culture. The osmoprotectant transporters proP, proU, and osmU (STM1491 to STM1494) were highly upregulated by drying. Deletion of any one of these transport systems resulted in a reduction in the long-term viability of S. Typhimurium on a stainless steel food contact surface. The proP gene was critical for survival; proP deletion mutants could not survive desiccation for long periods and were undetectable after 4 weeks. Following rehydration, 138 genes were differentially expressed, with upregulation observed for genes such as proP, proU, and the phosphate transport genes (pstACS). In time, this knowledge should prove valuable for understanding the underlying mechanisms involved in pathogen survival and should lead to improved methods for control to ensure the safety of intermediate- and low-moisture foods. PMID:23666329

  3. ProP Is Required for the Survival of Desiccated Salmonella enterica Serovar Typhimurium Cells on a Stainless Steel Surface

    PubMed Central

    Finn, Sarah; Händler, Kristian; Condell, Orla; Colgan, Aoife; Cooney, Shane; McClure, Peter; Amézquita, Aléjandro; Hinton, Jay C. D.

    2013-01-01

    Consumers trust commercial food production to be safe, and it is important to strive to improve food safety at every level. Several outbreaks of food-borne disease have been caused by Salmonella strains associated with dried food. Currently we do not know the mechanisms used by Salmonella enterica serovar Typhimurium to survive in desiccated environments. The aim of this study was to discover the responses of S. Typhimurium ST4/74 at the transcriptional level to desiccation on a stainless steel surface and to subsequent rehydration. Bacterial cells were dried onto the same steel surfaces used during the production of dry foods, and RNA was recovered for transcriptomic analysis. Subsequently, dried cells were rehydrated and were again used for transcriptomic analysis. A total of 266 genes were differentially expressed under desiccation stress compared with a static broth culture. The osmoprotectant transporters proP, proU, and osmU (STM1491 to STM1494) were highly upregulated by drying. Deletion of any one of these transport systems resulted in a reduction in the long-term viability of S. Typhimurium on a stainless steel food contact surface. The proP gene was critical for survival; proP deletion mutants could not survive desiccation for long periods and were undetectable after 4 weeks. Following rehydration, 138 genes were differentially expressed, with upregulation observed for genes such as proP, proU, and the phosphate transport genes (pstACS). In time, this knowledge should prove valuable for understanding the underlying mechanisms involved in pathogen survival and should lead to improved methods for control to ensure the safety of intermediate- and low-moisture foods. PMID:23666329

  4. Outbreak of unusual Salmonella enterica serovar Typhimurium monophasic variant 1,4 [5],12:i:-, Italy, June 2013 to September 2014.

    PubMed

    Cito, Francesca; Baldinelli, Francesca; Calistri, Paolo; Di Giannatale, Elisabetta; Scavia, Gaia; Orsini, Massimiliano; Iannetti, Simona; Sacchini, Lorena; Mangone, Iolanda; Candeloro, Luca; Conte, Annamaria; Ippoliti, Carla; Morelli, Daniela; Migliorati, Giacomo; Barile, Nadia Beatrice; Marfoglia, Cristina; Salucci, Stefania; Cammà, Cesare; Marcacci, Maurilia; Ancora, Massimo; Dionisi, Anna Maria; Owczartek, Slawomir; Luzzi, Ida

    2016-04-14

    Monophasic variant of Salmonella enterica subspecies enterica serovar Typhimurium (monophasic S. Typhimurium), with antigenic structure 1,4,[5],12:i:-, appears to be of increasing importance in Europe. In Italy, monophasic S. Typhimurium represented the third most frequent Salmonella serovar isolated from human cases between 2004 and 2008. From June 2013 to October 2014, a total of 206 human cases of salmonellosis were identified in Abruzzo region (Central Italy). Obtained clinical isolates characterised showed S. Typhimurium 1,4,[5],12:i:- with sole resistance to nalidixic acid, which had never been observed in Italy in monophasic S. Typhimurium, neither in humans nor in animals or foods. Epidemiological, microbiological and environmental investigations were conducted to try to identify the outbreak source. Cases were interviewed using a standardised questionnaire and microbiological tests were performed on human as well as environmental samples, including samples from fruit and vegetables, pigs, and surface water. Investigation results did not identify the final vehicle of human infection, although a link between the human cases and the contamination of irrigation water channels was suggested. PMID:27105170

  5. Impairment of swimming motility by antidiarrheic Lactobacillus acidophilus strain LB retards internalization of Salmonella enterica serovar Typhimurium within human enterocyte-like cells.

    PubMed

    Liévin-Le Moal, Vanessa; Amsellem, Raymonde; Servin, Alain L

    2011-10-01

    We report that both culture and the cell-free culture supernatant (CFCS) of Lactobacillus acidophilus strain LB (Lactéol Boucard) have the ability (i) to delay the appearance of Salmonella enterica serovar Typhimurium strain SL1344-induced mobilization of F-actin and, subsequently, (ii) to retard cell entry by S. Typhimurium SL1344. Time-lapse imaging and Western immunoblotting showed that S. Typhimurium SL1344 swimming motility, as represented by cell tracks of various types, was rapidly but temporarily blocked without affecting the expression of FliC flagellar propeller protein. We show that the product(s) secreted by L. acidophilus LB that supports the inhibitory activity is heat stable and of low molecular weight. The product(s) caused rapid depolarization of the S. Typhimurium SL1344 cytoplasmic membrane without affecting bacterial viability. We identified inhibition of swimming motility as a newly discovered mechanism by which the secreted product(s) of L. acidophilus strain LB retards the internalization of the diarrhea-associated pathogen S. enterica serovar Typhimurium within cultured human enterocyte-like cells. PMID:21825295

  6. The transcriptional programme of Salmonella enterica serovar Typhimurium reveals a key role for tryptophan metabolism in biofilms

    PubMed Central

    2009-01-01

    Background Biofilm formation enhances the capacity of pathogenic Salmonella bacteria to survive stresses that are commonly encountered within food processing and during host infection. The persistence of Salmonella within the food chain has become a major health concern, as biofilms can serve as a reservoir for the contamination of food products. While the molecular mechanisms required for the survival of bacteria on surfaces are not fully understood, transcriptional studies of other bacteria have demonstrated that biofilm growth triggers the expression of specific sets of genes, compared with planktonic cells. Until now, most gene expression studies of Salmonella have focused on the effect of infection-relevant stressors on virulence or the comparison of mutant and wild-type bacteria. However little is known about the physiological responses taking place inside a Salmonella biofilm. Results We have determined the transcriptomic and proteomic profiles of biofilms of Salmonella enterica serovar Typhimurium. We discovered that 124 detectable proteins were differentially expressed in the biofilm compared with planktonic cells, and that 10% of the S. Typhimurium genome (433 genes) showed a 2-fold or more change in the biofilm compared with planktonic cells. The genes that were significantly up-regulated implicated certain cellular processes in biofilm development including amino acid metabolism, cell motility, global regulation and tolerance to stress. We found that the most highly down-regulated genes in the biofilm were located on Salmonella Pathogenicity Island 2 (SPI2), and that a functional SPI2 secretion system regulator (ssrA) was required for S. Typhimurium biofilm formation. We identified STM0341 as a gene of unknown function that was needed for biofilm growth. Genes involved in tryptophan (trp) biosynthesis and transport were up-regulated in the biofilm. Deletion of trpE led to decreased bacterial attachment and this biofilm defect was restored by exogenous

  7. Effects of Leachate from Crumb Rubber and Zinc in Green Roofs on the Survival, Growth, and Resistance Characteristics of Salmonella enterica subsp. enterica Serovar Typhimurium

    PubMed Central

    Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H.

    2014-01-01

    The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain. PMID:24584242

  8. Effects of leachate from crumb rubber and zinc in green roofs on the survival, growth, and resistance characteristics of Salmonella enterica subsp. enterica serovar Typhimurium.

    PubMed

    Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H; Herson, Diane S

    2014-05-01

    The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain. PMID:24584242

  9. Molecular fingerprinting of Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica derby isolated from tropical seafood in South India.

    PubMed

    Kumar, Rakesh; Surendran, P K; Thampuran, Nirmala

    2008-09-01

    Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica Derby strains isolated from different seafood were genotyped by PCR-ribotyping and ERIC-PCR assays. This study has ascertained the genetic relatedness among serovars prevalent in tropical seafood. PCR-ribotyping exhibited genetic variation in both Salmonella serovars, and ribotype profile (II) was most predominant, which was observed in 10/18 of Salmonella enterica subsp. enterica Typhimurium and 7/17 Salmonella enterica subsp. enterica Derby isolates. Cluster analysis of ERIC-PCR for Salmonella enterica subsp. enterica Typhimurium strains exhibited nine different banding patterns and four strains showed >95% genetic homology within the cluster pairs. ERIC-PCR produced more genetic variations in Salmonella enterica subsp. enterica Typhimurium; nevertheless, both methods were found to be comparable for Salmonella enterica subsp. enterica Derby isolates. Discrimination index of PCR-ribotyping for Salmonella enterica subsp. enterica Typhimurium isolates was obtained at 0.674 and index value 0.714 was observed for Salmonella enterica subsp. enterica Derby strains. Molecular fingerprinting investigation highlighted the hypothesis of diverse routes of Salmonella contamination in seafood as multiple clones of Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica Derby were detected in same or different seafood throughout the study period. PMID:18480975

  10. Induction of fatty acid composition modifications and tolerance to biocides in Salmonella enterica serovar Typhimurium by plant-derived terpenes.

    PubMed

    Dubois-Brissonnet, Florence; Naïtali, Murielle; Mafu, Akier Assanta; Briandet, Romain

    2011-02-01

    To enhance food safety and stability, the food industry tends to use natural antimicrobials such as plant-derived compounds as an attractive alternative to chemical preservatives. Nonetheless, caution must be exercised in light of the potential for bacterial adaptation to these molecules, a phenomenon previously observed with other antimicrobials. The aim of this study was to characterize the adaptation of Salmonella enterica serovar Typhimurium to sublethal concentrations of four terpenes extracted from aromatic plants: thymol, carvacrol, citral, and eugenol, or combinations thereof. Bacterial adaptation in these conditions was demonstrated by changes in membrane fatty acid composition showing (i) limitation of the cyclization of unsaturated fatty acids to cyclopropane fatty acids when cells entered the stationary phase and (ii) bacterial membrane saturation. Furthermore, we demonstrated an increased cell resistance to the bactericidal activity of two biocides (peracetic acid and didecyl dimethyl ammonium bromide). The implications of membrane modifications in terms of hindering the penetration of antimicrobials through the bacterial membrane are discussed. PMID:21131520

  11. Comparison of the sensitivity of strains of Salmonella enterica serovar Typhimurium in the detection of mutagenicity induced by nitroarenes.

    PubMed

    Rainho, C R; Corrêa, S M; Mazzei, J L; Aiub, C A F; Felzenszwalb, I

    2014-01-01

    The use of strains of Salmonella enterica serovar Typhimurium with different metabolic capacities can indicate the class or classes of compounds present in an environmental sample and enable the diagnosis of the mutagenic activity of these pollutants adsorbed on particulate matter (PM) in the air. In the present study, the sensitivity of Salmonella strains TA98NR, TA98/1,8-DNP₆, YG1021, and YG1024 to detect nitro compounds adsorbed on samples of PM 2.5 was compared from three sites in Rio de Janeiro city. Samples were collected using a high-volume sampler at three sites: one with light traffic and two with heavy traffic. The assays were performed in the presence of 10-50 μg/ plate organic extracts with and without exogenous metabolization. The YG1021 and YG1024 strains showed the highest rev/m(3) values, confirming their enhanced sensitivity. As YG1024 also demonstrated sensitivity to nitro and amino compounds, we suggest its use in research into environmental contamination. PMID:24854446

  12. Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants

    SciTech Connect

    Niemann, George; Brown, Roslyn N.; Gustin, Jean K.; Stufkens, Afke; Shaikh-Kidwai, Afshan S.; Li, Jie; McDermott, Jason E.; Brewer, Heather M.; Schepmoes, Athena A.; Smith, Richard D.; Adkins, Joshua N.; Heffron, Fred

    2011-01-01

    The intracellular pathogen Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis in the world. This pathogen has two type-III secretion systems (TTSS) necessary for virulence that are encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) and are expressed during extracellular or intracellular infectious states, respectively, to deliver virulence factors (effectors) to the host cell cytoplasm. While many have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this mass spectrometry-based proteomics study, we identified effector proteins secreted under minimal acidic medium growth conditions that induced the SPI-2 TTSS and its effectors, and compared the secretome from the parent strain to the secretome from strains missing either essential (SsaK) or regulatory components (SsaL) of the SPI-2 secretion apparatus. We identified 75% of the known TTSS effector repertoire. Excluding translocon components, 95% of the known effectors were biased for identification in the ssaL mutant background, which demonstrated that SsaL regulates SPI-2 type III secretion. To confirm secretion to animal cells, we made translational fusions of several of the best candidates to the calmodulin-dependent adenylate cyclase of Bordetella pertussis and assayed cAMP levels of infected J774 macrophage-like cells. From these infected cells we identified six new TTSS effectors and two others that are secreted independent of TTSS. Our results substantiate reports of additional secretion systems encoded by Salmonella other than TTSS.

  13. Structural and functional characterization of Salmonella enterica serovar Typhimurium YcbL: An unusual Type II glyoxalase

    PubMed Central

    Stamp, Anna L; Owen, Paul; Omari, Kamel El; Nichols, Charles E; Lockyer, Michael; Lamb, Heather K; Charles, Ian G; Hawkins, Alastair R; Stammers, David K

    2010-01-01

    YcbL has been annotated as either a metallo-β-lactamase or glyoxalase II (GLX2), both members of the zinc metallohydrolase superfamily, that contains many enzymes with a diverse range of activities. Here, we report crystallographic and biochemical data for Salmonella enterica serovar Typhimurium YcbL that establishes it as GLX2, which differs in certain structural and functional properties compared with previously known examples. These features include the insertion of an α-helix after residue 87 in YcbL and truncation of the C-terminal domain, which leads to the loss of some recognition determinants for the glutathione substrate. Despite these changes, YcbL has robust GLX2 activity. A further difference is that the YcbL structure contains only a single bound metal ion rather than the dual site normally observed for GLX2s. Activity assays in the presence of various metal ions indicate an increase in activity above basal levels in the presence of manganous and ferrous ions. Thus, YcbL represents a novel member of the GLX2 family. PMID:20669241

  14. Tumor Invasion of Salmonella enterica Serovar Typhimurium Is Accompanied by Strong Hemorrhage Promoted by TNF-α

    PubMed Central

    Dietrich, Nicole; Viegas, Nuno; Jablonska, Jadwiga; Lyszkiewicz, Marcin; Lienenklaus, Stefan; Falk, Werner; Gekara, Nelson; Loessner, Holger; Weiss, Siegfried

    2009-01-01

    Background Several facultative anaerobic bacteria with potential therapeutic abilities are known to preferentially colonize solid tumors after systemic administration. How they efficiently find and invade the tumors is still unclear. However, this is an important issue to be clarified when bacteria should be tailored for application in cancer therapy. Methodology/Principal Findings We describe the initial events of colonization of an ectopic transplantable tumor by Salmonella enterica serovar Typhimurium. Initially, after intravenous administration, bacteria were found in blood, spleen, and liver. Low numbers were also detected in tumors associated with blood vessels as could be observed by immunohistochemistry. A rapid increase of TNF-α in blood was observed at that time, in addition to other pro-inflammatory cytokines. This induced a tremendous influx of blood into the tumors by vascular disruption that could be visualized in H&E stainings and quantified by hemoglobin measurements of tumor homogenate. Most likely, together with the blood, bacteria were flushed into the tumor. In addition, blood influx was followed by necrosis formation, bacterial growth, and infiltration of neutrophilic granulocytes. Depletion of TNF-α retarded blood influx and delayed bacterial tumor-colonization. Conclusion Our findings emphasize similarities between Gram-negative tumor-colonizing bacteria and tumor vascular disrupting agents and show the involvement of TNF-α in the initial phase of tumor-colonization by bacteria. PMID:19693266

  15. Dormant intracellular Salmonella enterica serovar Typhimurium discriminates among Salmonella pathogenicity island 2 effectors to persist inside fibroblasts.

    PubMed

    Núñez-Hernández, Cristina; Alonso, Ana; Pucciarelli, M Graciela; Casadesús, Josep; García-del Portillo, Francisco

    2014-01-01

    Salmonella enterica uses effector proteins delivered by type III secretion systems (TTSS) to colonize eukaryotic cells. Recent in vivo studies have shown that intracellular bacteria activate the TTSS encoded by Salmonella pathogenicity island-2 (SPI-2) to restrain growth inside phagocytes. Growth attenuation is also observed in vivo in bacteria colonizing nonphagocytic stromal cells of the intestinal lamina propria and in cultured fibroblasts. SPI-2 is required for survival of nongrowing bacteria persisting inside fibroblasts, but its induction mode and the effectors involved remain unknown. Here, we show that nongrowing dormant intracellular bacteria use the two-component system OmpR-EnvZ to induce SPI-2 expression and the PhoP-PhoQ system to regulate the time at which induction takes place, 2 h postentry. Dormant bacteria were shown to discriminate the usage of SPI-2 effectors. Among the effectors tested, SseF, SseG, and SseJ were required for survival, while others, such as SifA and SifB, were not. SifA and SifB dispensability correlated with the inability of intracellular bacteria to secrete these effectors even when overexpressed. Conversely, SseJ overproduction resulted in augmented secretion and exacerbated bacterial growth. Dormant bacteria produced other effectors, such as PipB and PipB2, that, unlike what was reported for epithelial cells, did not to traffic outside the phagosomal compartment. Therefore, permissiveness for secreting only a subset of SPI-2 effectors may be instrumental for dormancy. We propose that the S. enterica serovar Typhimurium nonproliferative intracellular lifestyle is sustained by selection of SPI-2 effectors that are produced in tightly defined amounts and delivered to phagosome-confined locations. PMID:24144726

  16. Exposure of Salmonella enterica Serovar Typhimurium to Three Humectants Used in the Food Industry Induces Different Osmoadaptation Systems.

    PubMed

    Finn, Sarah; Rogers, Lisa; Händler, Kristian; McClure, Peter; Amézquita, Alejandro; Hinton, Jay C D; Fanning, Séamus

    2015-10-01

    Common salt (NaCl) is frequently used by the food industry to add flavor and to act as a humectant in order to reduce the water content of a food product. The improved health awareness of consumers is leading to a demand for food products with reduced salt content; thus, manufacturers require alternative water activity-reducing agents which elicit the same general effects as NaCl. Two examples include KCl and glycerol. These agents lower the water activity of a food matrix and also contribute to limit the growth of the microbiota, including foodborne pathogens. Little is currently known about how foodborne pathogens respond to these water activity-lowering agents. Here we examined the response of Salmonella enterica serovar Typhimurium 4/74 to NaCl, KCl, and glycerol at three time points, using a constant water activity level, compared with the response of a control inoculum. All conditions induced the upregulation of gluconate metabolic genes after 6 h of exposure. Bacteria exposed to NaCl and KCl demonstrated the upregulation of the osmoprotective transporter mechanisms encoded by the proP, proU, and osmU (STM1491 to STM1494) genes. Glycerol exposure elicited the downregulation of these osmoadaptive mechanisms but stimulated an increase in lipopolysaccharide and membrane protein-associated genes after 1 h. The most extensive changes in gene expression occurred following exposure to KCl. Because many of these genes were of unknown function, further characterization may identify KCl-specific adaptive processes that are not stimulated by NaCl. This study shows that the response of S. Typhimurium to different humectants does not simply reflect reduced water activity and likely involves systems that are linked to specific humectants. PMID:26209672

  17. Structural and Functional Characterization of ScsC, a Periplasmic Thioredoxin-Like Protein from Salmonella enterica Serovar Typhimurium

    PubMed Central

    Shepherd, Mark; Heras, Begoña; Achard, Maud E. S.; King, Gordon J.; Argente, M. Pilar; Kurth, Fabian; Taylor, Samantha L.; Howard, Mark J.; King, Nathan P.

    2013-01-01

    Abstract Aims: The prototypical protein disulfide bond (Dsb) formation and protein refolding pathways in the bacterial periplasm involving Dsb proteins have been most comprehensively defined in Escherichia coli. However, genomic analysis has revealed several distinct Dsb-like systems in bacteria, including the pathogen Salmonella enterica serovar Typhimurium. This includes the scsABCD locus, which encodes a system that has been shown via genetic analysis to confer copper tolerance, but whose biochemical properties at the protein level are not defined. The aim of this study was to provide functional insights into the soluble ScsC protein through structural, biochemical, and genetic analyses. Results: Here we describe the structural and biochemical characterization of ScsC, the soluble DsbA-like component of this system. Our crystal structure of ScsC reveals a similar overall fold to DsbA, although the topology of β-sheets and α-helices in the thioredoxin domains differ. The midpoint reduction potential of the CXXC active site in ScsC was determined to be −132 mV versus normal hydrogen electrode. The reactive site cysteine has a low pKa, typical of the nucleophilic cysteines found in DsbA-like proteins. Deletion of scsC from S. Typhimurium elicits sensitivity to copper (II) ions, suggesting a potential involvement for ScsC in disulfide folding under conditions of copper stress. Innovation and Conclusion: ScsC is a novel disulfide oxidoreductase involved in protection against copper ion toxicity. Antioxid. Redox Signal. 19, 1494–1506. PMID:23642141

  18. Loss of Multicellular Behavior in Epidemic African Nontyphoidal Salmonella enterica Serovar Typhimurium ST313 Strain D23580

    PubMed Central

    Singletary, Larissa A.; Karlinsey, Joyce E.; Libby, Stephen J.; Mooney, Jason P.; Lokken, Kristen L.; Tsolis, Renée M.; Byndloss, Mariana X.; Hirao, Lauren A.; Gaulke, Christopher A.; Crawford, Robert W.; Dandekar, Satya; Kingsley, Robert A.; Msefula, Chisomo L.; Heyderman, Robert S.

    2016-01-01

    ABSTRACT Nontyphoidal Salmonella enterica serovar Typhimurium is a frequent cause of bloodstream infections in children and HIV-infected adults in sub-Saharan Africa. Most isolates from African patients with bacteremia belong to a single sequence type, ST313, which is genetically distinct from gastroenteritis-associated ST19 strains, such as 14028s and SL1344. Some studies suggest that the rapid spread of ST313 across sub-Saharan Africa has been facilitated by anthroponotic (person-to-person) transmission, eliminating the need for Salmonella survival outside the host. While these studies have not ruled out zoonotic or other means of transmission, the anthroponotic hypothesis is supported by evidence of extensive genomic decay, a hallmark of host adaptation, in the sequenced ST313 strain D23580. We have identified and demonstrated 2 loss-of-function mutations in D23580, not present in the ST19 strain 14028s, that impair multicellular stress resistance associated with survival outside the host. These mutations result in inactivation of the KatE stationary-phase catalase that protects high-density bacterial communities from oxidative stress and the BcsG cellulose biosynthetic enzyme required for the RDAR (red, dry, and rough) colonial phenotype. However, we found that like 14028s, D23580 is able to elicit an acute inflammatory response and cause enteritis in mice and rhesus macaque monkeys. Collectively, these observations suggest that African S. Typhimurium ST313 strain D23580 is becoming adapted to an anthroponotic mode of transmission while retaining the ability to infect and cause enteritis in multiple host species. PMID:26933058

  19. Exposure of Salmonella enterica Serovar Typhimurium to Three Humectants Used in the Food Industry Induces Different Osmoadaptation Systems

    PubMed Central

    Finn, Sarah; Rogers, Lisa; Händler, Kristian; McClure, Peter; Amézquita, Alejandro; Hinton, Jay C. D.

    2015-01-01

    Common salt (NaCl) is frequently used by the food industry to add flavor and to act as a humectant in order to reduce the water content of a food product. The improved health awareness of consumers is leading to a demand for food products with reduced salt content; thus, manufacturers require alternative water activity-reducing agents which elicit the same general effects as NaCl. Two examples include KCl and glycerol. These agents lower the water activity of a food matrix and also contribute to limit the growth of the microbiota, including foodborne pathogens. Little is currently known about how foodborne pathogens respond to these water activity-lowering agents. Here we examined the response of Salmonella enterica serovar Typhimurium 4/74 to NaCl, KCl, and glycerol at three time points, using a constant water activity level, compared with the response of a control inoculum. All conditions induced the upregulation of gluconate metabolic genes after 6 h of exposure. Bacteria exposed to NaCl and KCl demonstrated the upregulation of the osmoprotective transporter mechanisms encoded by the proP, proU, and osmU (STM1491 to STM1494) genes. Glycerol exposure elicited the downregulation of these osmoadaptive mechanisms but stimulated an increase in lipopolysaccharide and membrane protein-associated genes after 1 h. The most extensive changes in gene expression occurred following exposure to KCl. Because many of these genes were of unknown function, further characterization may identify KCl-specific adaptive processes that are not stimulated by NaCl. This study shows that the response of S. Typhimurium to different humectants does not simply reflect reduced water activity and likely involves systems that are linked to specific humectants. PMID:26209672

  20. Salmonella enterica Serovars Typhi and Paratyphi A are avirulent in newborn and infant mice even when expressing virulence plasmid genes of Salmonella Typhimurium

    PubMed Central

    Javier Santander, M.; Curtiss, Roy

    2014-01-01

    Background Salmonella enterica serovars Typhi and Paratyphi A are human host-restricted pathogens. Therefore, there is no small susceptible animal host that can be used to assess the virulence and safety of vaccine strains derived from these Salmonella serovars. However, infant mice have been used to evaluate virulence and colonization by another human host-restricted pathogen, Vibrio cholerae. Methodology The possibility that infant mice host could be adapted for Salmonella led us to investigate the susceptibility of newborn and infant mice to oral infection with S. Typhi and S. Paratyphi A. Salmonella enterica serovar Typhimurium causes enteric fever in adult mice and this system has been used as a model for human typhoid. The pSTV virulence plasmid, not present in S. Typhi and S. Paratyphi A, plays an essential role in S. Typhimurium colonization and systemic infection of mice. We also conjugated pSTV into S. Typhi and S. Paratyphi A serovars and evaluated these transconjugants in newborn and infant mice. Results We determined that the spv virulence genes from the S. Typhimurium virulence plasmid are expressed in S. Typhi and S. Paratyphi A in a RpoS dependent fashion. Also, we determined that S. Typhi and S. Paratyphi A with and without pSTV transiently colonize newborn and infant mice tissues. Conclusion Newborn and infant mice infected with S. Typhi and S. Paratyphi A do not succumb to the infection and that carriage of the S. Typhimurium virulence plasmid, pSTV, did not influence these results. PMID:21252450

  1. Association of virulence plasmid and antibiotic resistance determinants with chromosomal multilocus genotypes in Mexican Salmonella enterica serovar Typhimurium strains

    PubMed Central

    2009-01-01

    Background Bacterial genomes are mosaic structures composed of genes present in every strain of the same species (core genome), and genes present in some but not all strains of a species (accessory genome). The aim of this study was to compare the genetic diversity of core and accessory genes of a Salmonella enterica subspecies enterica serovar Typhimurium (Typhimurium) population isolated from food-animal and human sources in four regions of Mexico. Multilocus sequence typing (MLST) and macrorestriction fingerprints by pulsed-field gel electrophoresis (PFGE) were used to address the core genetic variation, and genes involved in pathogenesis and antibiotic resistance were selected to evaluate the accessory genome. Results We found a low genetic diversity for both housekeeping and accessory genes. Sequence type 19 (ST19) was supported as the founder genotype of STs 213, 302 and 429. We found a temporal pattern in which the derived ST213 is replacing the founder ST19 in the four geographic regions analyzed and a geographic trend in the number of resistance determinants. The distribution of the accessory genes was not random among chromosomal genotypes. We detected strong associations among the different accessory genes and the multilocus chromosomal genotypes (STs). First, the Salmonella virulence plasmid (pSTV) was found mostly in ST19 isolates. Second, the plasmid-borne betalactamase cmy-2 was found only in ST213 isolates. Third, the most abundant integron, IP-1 (dfrA12, orfF and aadA2), was found only in ST213 isolates. Fourth, the Salmonella genomic island (SGI1) was found mainly in a subgroup of ST19 isolates carrying pSTV. The mapping of accessory genes and multilocus genotypes on the dendrogram derived from macrorestiction fingerprints allowed the establishment of genetic subgroups within the population. Conclusion Despite the low levels of genetic diversity of core and accessory genes, the non-random distribution of the accessory genes across chromosomal

  2. H-NS Silencing of the Salmonella Pathogenicity Island 6-Encoded Type VI Secretion System Limits Salmonella enterica Serovar Typhimurium Interbacterial Killing

    PubMed Central

    Brunet, Yannick R.; Khodr, Ahmad; Logger, Laureen; Aussel, Laurent; Mignot, Tâm; Rimsky, Sylvie

    2015-01-01

    The secretion of bacterial toxin proteins is achieved by dedicated machineries called secretion systems. The type VI secretion system (T6SS) is a widespread versatile machine used for the delivery of protein toxins to both prokaryotic and eukaryotic cells. In Salmonella enterica serovar Typhimurium, the expression of the T6SS genes is activated during macrophage or mouse infection. Here, we show that the T6SS gene cluster is silenced by the histone-like nucleoid structuring H-NS protein using a combination of reporter fusions, electrophoretic mobility shift assays, DNase footprinting, and fluorescence microscopy. We further demonstrate that derepression of the S. Typhimurium T6SS genes induces T6SS-dependent intoxication of competing bacteria. Our results suggest that relieving T6SS H-NS silencing may be used as a sense-and-kill mechanism that will help S. Typhimurium to homogenize and synchronize the microbial population to gain efficiency during infection. PMID:25916986

  3. H-NS Silencing of the Salmonella Pathogenicity Island 6-Encoded Type VI Secretion System Limits Salmonella enterica Serovar Typhimurium Interbacterial Killing.

    PubMed

    Brunet, Yannick R; Khodr, Ahmad; Logger, Laureen; Aussel, Laurent; Mignot, Tâm; Rimsky, Sylvie; Cascales, Eric

    2015-07-01

    The secretion of bacterial toxin proteins is achieved by dedicated machineries called secretion systems. The type VI secretion system (T6SS) is a widespread versatile machine used for the delivery of protein toxins to both prokaryotic and eukaryotic cells. In Salmonella enterica serovar Typhimurium, the expression of the T6SS genes is activated during macrophage or mouse infection. Here, we show that the T6SS gene cluster is silenced by the histone-like nucleoid structuring H-NS protein using a combination of reporter fusions, electrophoretic mobility shift assays, DNase footprinting, and fluorescence microscopy. We further demonstrate that derepression of the S. Typhimurium T6SS genes induces T6SS-dependent intoxication of competing bacteria. Our results suggest that relieving T6SS H-NS silencing may be used as a sense-and-kill mechanism that will help S. Typhimurium to homogenize and synchronize the microbial population to gain efficiency during infection. PMID:25916986

  4. Differences in Host Cell Invasion and Salmonella Pathogenicity Island 1 Expression between Salmonella enterica Serovar Paratyphi A and Nontyphoidal S. Typhimurium.

    PubMed

    Elhadad, Dana; Desai, Prerak; Grassl, Guntram A; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

    2016-04-01

    Active invasion into nonphagocytic host cells is central to Salmonella enterica pathogenicity and dependent on multiple genes within Salmonella pathogenicity island 1 (SPI-1). Here, we explored the invasion phenotype and the expression of SPI-1 in the typhoidal serovarS Paratyphi A compared to that of the nontyphoidal serovarS Typhimurium. We demonstrate that while S. Typhimurium is equally invasive under both aerobic and microaerobic conditions, S. Paratyphi A invades only following growth under microaerobic conditions. Transcriptome sequencing (RNA-Seq), reverse transcription-PCR (RT-PCR), Western blot, and secretome analyses established that S. Paratyphi A expresses much lower levels of SPI-1 genes and secretes lesser amounts of SPI-1 effector proteins than S. Typhimurium, especially under aerobic growth. Bypassing the native SPI-1 regulation by inducible expression of the SPI-1 activator, HilA, considerably elevated SPI-1 gene expression, host cell invasion, disruption of epithelial integrity, and induction of proinflammatory cytokine secretion by S. Paratyphi A but not by S. Typhimurium, suggesting that SPI-1 expression is naturally downregulated inS Paratyphi A. Using streptomycin-treated mice, we were able to establish substantial intestinal colonization byS Paratyphi A and showed moderately higher pathology and intestinal inflammation in mice infected with S. Paratyphi A overexpressing hilA Collectively, our results reveal unexpected differences in SPI-1 expression between S. Paratyphi A andS Typhimurium, indicate that S. Paratyphi A host cell invasion is suppressed under aerobic conditions, and suggest that lower invasion in aerobic sites and suppressed expression of immunogenic SPI-1 components contributes to the restrained inflammatory infection elicited by S. Paratyphi A. PMID:26857569

  5. Identification of multidrug-resistant Salmonella enterica serovar typhimurium isolates that have an antibiotic-induced invasion phenotype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multidrug-resistant (MDR) Salmonella is an important food safety issue in humans and animals. The National Antimicrobial Resistance Monitoring System (NARMS) has reported that 27.3% of Salmonella enterica serotype Typhimurium isolates in humans were resistant to three or more classes of antibiotics...

  6. The O-Antigen Capsule of Salmonella enterica Serovar Typhimurium Facilitates Serum Resistance and Surface Expression of FliC

    PubMed Central

    Marshall, Joanna M.

    2015-01-01

    Group IV polysaccharide capsules are common in enteric bacteria and have more recently been described in nontyphoidal Salmonella species. Such capsules are known as O-antigen (O-Ag) capsules, due to their high degree of similarity to the O-Ag of the lipopolysaccharide (LPSO-Ag). Capsular polysaccharides are known virulence factors of many bacterial pathogens, facilitating evasion of immune recognition and systemic dissemination within the host. Previous studies on the O-Ag capsule of salmonellae have focused primarily on its role in bacterial surface attachment and chronic infection; however, the potential effects of the O-Ag capsule on acute pathogenesis have yet to be investigated. While much of the in vivo innate immune resistance of Salmonella enterica serovar Typhimurium is attributed to the high-molecular-weight LPS, we hypothesized that the O-Ag capsule may enhance this resistance by diminishing surface expression of pathogen-associated molecular patterns, such as flagella, and increasing resistance to host immune molecules. To test this hypothesis, O-Ag capsule-deficient mutants were constructed, and the loss of O-Ag capsular surface expression was confirmed through microscopy and immunoblotting. Loss of O-Ag capsule production did not alter bacterial growth or production of LPS. Western blot analysis and confocal microscopy revealed that O-Ag capsule-deficient mutants demonstrate reduced resistance to killing by human serum. Furthermore, O-Ag capsule-deficient mutants produced exclusively phase I flagellin (FliC). Although O-Ag capsule-deficient mutants did not exhibit reduced virulence in a murine model of acute infection, in vitro results indicate that the O-Ag capsule may function to modify the antigenic nature of the bacterial surface, warranting additional investigation of a potential role of the structure in pathogenesis. PMID:26195553

  7. Regulation of the AcrAB multidrug efflux pump in Salmonella enterica serovar Typhimurium in response to indole and paraquat.

    PubMed

    Nikaido, Eiji; Shirosaka, Ikue; Yamaguchi, Akihito; Nishino, Kunihiko

    2011-03-01

    Salmonella enterica serovar Typhimurium has at least nine multidrug efflux pumps. Among these, AcrAB is constitutively expressed and is the most efficient, playing a role in both drug resistance and virulence. The acrAB locus is induced by indole, Escherichia coli-conditioned medium, and bile salts. This induction is dependent on RamA through the binding sequence in the upstream region of acrA that binds RamA. In the present study, we made a detailed investigation of the ramA and acrAB induction mechanisms in Salmonella in response to indole, a biological oxidant for bacteria. We found that acrAB and ramA induction in response to indole is dependent on RamR. However, the cysteine residues of RamR do not play a role in the induction of ramA in response to indole, and the oxidative effect of indole is therefore not related to ramA induction via RamR. Furthermore, we showed that paraquat, a superoxide generator, induces acrAB but not ramA. We further discovered that the mechanism of acrAB induction in response to paraquat is dependent on SoxS. The data indicate that there are at least two independent induction pathways for acrAB in response to extracellular signals such as indole and paraquat. We propose that Salmonella utilizes these regulators for acrAB induction in response to extracellular signals in order to adapt itself to environmental conditions. PMID:21148208

  8. Expression of Antimicrobial Peptides in Cecal Tonsils of Chickens Treated with Probiotics and Infected with Salmonella enterica Serovar Typhimurium

    PubMed Central

    Akbari, Mohammad Reza; Haghighi, Hamid Reza; Chambers, James R.; Brisbin, Jennifer; Read, Leah R.; Sharif, Shayan

    2008-01-01

    Several strategies currently exist for control of Salmonella enterica serovar Typhimurium colonization in the chicken intestine, among which the use of probiotics is of note. Little is known about the underlying mechanisms of probiotic-mediated reduction of Salmonella colonization. In this study, we asked whether the effect of probiotics is mediated by antimicrobial peptides, including avian beta-defensins (also called gallinacins) and cathelicidins. Four treatment groups were included in this study: a negative-control group, a probiotic-treated group, a Salmonella-infected group, and a probiotic-treated and Salmonella-infected group. On days 1, 3, and 5 postinfection (p.i.), the cecal tonsils were removed, and RNA was extracted and used for measurement of avian beta-defensin 1 (AvBD1), AvBD2, AvBD4, AvBD6, and cathelicidin gene expression by real-time PCR. The expressions of all avian beta-defensins and cathelicidin were detectable in all groups, irrespective of treatment and time point. Probiotic treatment and Salmonella infection did not affect the expression of any of the investigated genes on day 1 p.i. Furthermore, probiotic treatment had no significant effect on the expression of the genes at either 3 or 5 days p.i. However, the expression levels of all five genes were significantly increased (P < 0.05) in response to Salmonella infection at 3 and 5 days p.i. However, administration of probiotics eliminated the effect of Salmonella infection on the expression of antimicrobial genes. These findings indicate that the expression of antimicrobial peptides may be repressed by probiotics in combination with Salmonella infection or, alternatively, point to the possibility that, due to a reduction in Salmonella load in the intestine, these genes may not be induced. PMID:18827189

  9. Low-Shear modeled microgravity alters the Salmonella enterica serovar typhimurium stress response in an RpoS-independent manner

    NASA Technical Reports Server (NTRS)

    Wilson, James W.; Ott, C. Mark; Ramamurthy, Rajee; Porwollik, Steffen; McClelland, Michael; Pierson, Duane L.; Nickerson, Cheryl A.

    2002-01-01

    We have previously demonstrated that low-shear modeled microgravity (low-shear MMG) serves to enhance the virulence of a bacterial pathogen, Salmonella enterica serovar Typhimurium. The Salmonella response to low-shear MMG involves a signaling pathway that we have termed the low-shear MMG stimulon, though the identities of the low-shear MMG stimulon genes and regulatory factors are not known. RpoS is the primary sigma factor required for the expression of genes that are induced upon exposure to different environmental-stress signals and is essential for virulence in mice. Since low-shear MMG induces a Salmonella acid stress response and enhances Salmonella virulence, we reasoned that RpoS would be a likely regulator of the Salmonella low-shear MMG response. Our results demonstrate that low-shear MMG provides cross-resistance to several environmental stresses in both wild-type and isogenic rpoS mutant strains. Growth under low-shear MMG decreased the generation time of both strains in minimal medium and increased the ability of both strains to survive in J774 macrophages. Using DNA microarray analysis, we found no evidence of induction of the RpoS regulon by low-shear MMG but did find that other genes were altered in expression under these conditions in both the wild-type and rpoS mutant strains. Our results indicate that, under the conditions of these studies, RpoS is not required for transmission of the signal that induces the low-shear MMG stimulon. Moreover, our studies also indicate that low-shear MMG can be added to a short list of growth conditions that can serve to preadapt an rpoS mutant for resistance to multiple environmental stresses.

  10. [Molecular characterization of Salmonella enterica serovar Typhimurium strains isolated from humans in Turkey].

    PubMed

    Dolapçı, İştar; Tekeli, Alper; Şahin, Fikret; Erdem, Birsel

    2015-10-01

    Multidrug resistant (MDR) Salmonella infections, especially infections due to Salmonella Typhimurium DT104 phage type strains are an important public health issue in many parts of the world. S.Typhimurium is the most common serotype isolated from clinical samples in Turkey but we have limited data about the phage types of these isolates. The aims of this study were to find out whether these MDR S.Typhimurium isolates are DT104 phage type isolates and have class 1 integrons and to investigate the relationships of these characteristics between plasmid and pulsed field gel electrophoresis (PFGE) profiles. A total of 66 S.Typhimurium stock strains selected from Enterobacteria Laboratory culture collections of Ankara University School of Medicine, Department of Medical Microbiology were investigated by plasmid profile analysis (PPA) and PFGE with the use of XbaI and SpeI enzymes. The presence of class 1 integrons and the phage type 104 were investigated by polymerase chain reaction (PCR). The strains used in the study were sporadically isolated cases from seven provinces after year 2000 with ACSSuT (63), ACGSSuTT/S (1), ACSSuTT/S (1) and ASSuTT/S (1) resistance types [ampicillin (A), chloramphenicol (C), gentamicin (G), streptomycin (S), sulphonamide (Su), tetracycline (T), trimethoprim/sulfamethoxazole (T/S)]. Of the isolates 65 were found as DT104 phage type. Forty-three S.Typhimurium DT104 isolates that carry class 1 integrons had five different bands between 350-1600 base pairs (bp); all of the isolates harbored 1-4 plasmids with sizes ranging from 1.0-180 kbp and 62 isolates had 90 kbp plasmid which was serotype specific and virulence related. S.Typhimurium DT104 isolates were grouped into five (X1-X5) and seven (S1-S7) profiles with XbaI and SpeI enzymes, respectively. When the profiles of the two enzymes were evaluated, 58 of the 65 (89.2%) isolates showed similar (X1.S1) profile. The molecular characteristics of the most S.Typhimurium isolates were clustered in

  11. The evaluation of clusters of hospital infections due to multidrug-resistant Salmonella enterica serovar typhimurium in the neonatal unit: a two-year experience.

    PubMed

    Ağin, Hasan; Ayhan, Fahri Yüce; Gülay, Zeynep; Gülfidan, Gamze; Yaşar, Nevbahar; Eraç, Bayri; Devrim, Ilker

    2011-01-01

    Seven clusters of hospital infection due to Salmonella enterica serovar typhimurium were documented in the neonatology clinic of a children's hospital between April 2002 and March 2004. Eighty-one neonates were infected. Three cases were asymptomatic, 73 cases had gastroenteritis as the only clinical condition, and 5 cases had bacteremia associated with gastroenteritis. All isolates from stool and blood samples (n=86) were identified as Salmonella enterica serovar typhimurium. Extended-spectrum beta-lactamase (ESBL) production was determined by clavulanate disk potentiation assay in all isolates. Enterobacterial Repetitive Intergenic Consensus polymerase chain reaction (ERIC-PCR) was performed in 26 selected isolates, which were chosen as being representative of different clusters, to determine the clonal relationship. PCR, isoelectric focusing and sequence analysis revealed the production of CTX-M-3, TEM-1 and SHV-12 by these isolates in 23%, 76.9% and 100%, respectively. None of the isolates had PER beta-lactamase production. Standard infection control measures such as handwashing and disinfection procedures were implemented in initial clusters. During the two-year period, the infection control policy of the hospital was improved with appropriate actions such as assignment of an infection control nurse and increasing the number of staff of the clinic, and finally, with the establishment of an active surveillance program, the clusters were stopped. PMID:22272451

  12. Detection of Escherichia coli O157, Salmonella enterica serovar Typhimurium, and staphylococcal enterotoxin B in a single sample using enzymatic bio-nanotransduction.

    PubMed

    Branen, Josh R; Hass, Martha J; Douthit, Erin R; Maki, Wusi C; Branen, A Larry

    2007-04-01

    Enzymatic bio-nanotransduction is a biological detection scheme based on the production of nucleic acid nano-signals (RNA) in response to specific biological recognition events. In this study, we applied an enzymatic bio-nanotransduction system to the detection of important food-related pathogens and a toxin. Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and staphylococcal enterotoxin B (SEB) were chosen because of the implications of these targets to food safety. Primary antibodies to each of the targets were used to functionalize magnetic beads and produce biological recognition elements (antibodies) conjugated to nano-signal-producing DNA templates. Immunomagnetic capture that was followed by in vitro transcription of DNA templates bound to target molecules produced RNA nano-signals specific for every target in the sample. Discrimination of RNA nano-signals with a standard enzyme-linked oligonucleotide fluorescence assay provided a correlation between nano-signal profiles and target concentrations. The estimated limit of detection was 2.4 x 10(3) CFU/ml for E. coli O157:H7, 1.9 X 10(4) CFU/ml for S. enterica serovar Typhimurium, and 0.11 ng/ml for SEB with multianalyte detection in buffer. Low levels of one target were also detected in the presence of interference from high levels of the other targets. Finally, targets were detected in milk, and detection was improved for E. coli 0157 by heat treatment of the milk. PMID:17477251

  13. Gene regulation of Salmonella enterica serovar Typhimurium as influenced by LuxS/AI-2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quorum sensing is mediated by small signaling molecules, autoinducer molecules. The luxS gene which is conserved in several Gram-positive and Gram-negative bacteria is involved in the synthesis of the autoinducer molecule-2 (AI-2). Genes controlled by luxS in S. Typhimurium were identified using mic...

  14. Coptidis rhizome and Si Jun Zi Tang Can Prevent Salmonella enterica Serovar Typhimurium Infection in Mice

    PubMed Central

    Chang, Chiung-Hung; Yu, Bi; Su, Chiu-Hsian; Chen, Daniel S.; Hou, Yu-Chi; Chen, Yueh-Sheng; Hsu, Yuan-Man

    2014-01-01

    Salmonella, a common zoonotic pathogen, causes gastroenteritis in both humans and animals. Traditional Chinese Medicine (TCM) has been used to improve gastrointestinal dysfunction and to modify the immune response to inflammation for centuries. This study used six herbal plants and four TCM formulae to rate their efficacy in preventing S. Typhimurium infection via mouse model. Minimum bactericidal concentration (MBC) of Coptidis rhizome (CR) against the reference strain tallied 12.5 mg/ml and against clinical isolate ST21 was 25 mg/ml. MBCs of other herbal extracts and formulae on Salmonella Typhimurium strains were above 50 mg/ml. In the mice model, CR and Si Jun Zi Tang (SJZT) could significantly decrease the bacterial load in organs and blood after being challenged, along with body weight loss due to the infection. CR and SJZT alleviated infection-induced interferon-gamma levels in the serum and tissues, and tumor necrosis factor-alpha (TNF-α) levels in intestinal tissues. CR and SJZT serum metabolites could suppress S. Typhimurium invasion and TNF-α expression in RAW264.7 cells. The therapeutic activity of CR and SJZT may involve berberine, ginsenoside Rb1, and glycyrrhizin, interfering with Salmonella when invading macrophages. CR and SJZT has shown potential in preventing S. Typhimurium infection through the regulation of the immune response. PMID:25133542

  15. Isolation of QseC-regulated genes in Salmonella enterica serovar Typhimurium by transposon mutgagenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-typhoidal Salmonella, a leading cause of U.S. foodborne disease and food-related deaths, often asymptomatically colonizes food-producing animals. In fact, >50% of U.S. swine production facilities test positive for Salmonella. The multidrug-resistant (MDR) Salmonella Typhimurium DT104 NCTC13348 c...

  16. A Mutation in the Putative Lysl-tRNA Synthetase Gene, PoxR of Salmonella enterica Serovar Typhimurium Results in Altered Protein Production, Elevated Susceptibility to Environmental Challenges and Decreased Swine Colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using signature-tagged mutagenesis, a mutation in the poxR gene of Salmonella enterica serovar Typhimurium was identified with decreased survival in an ex vivo swine stomach content assay(Bearson et al. Appl Environ Microbiol. 72:2829-36). Gastrointestinal colonization and fecal shedding of the pox...

  17. Complete Genome Sequence of a Human-Invasive Salmonella enterica Serovar Typhimurium Strain of the Emerging Sequence Type 213 Harboring a Multidrug Resistance IncA/C Plasmid and a blaCMY-2-Carrying IncF Plasmid

    PubMed Central

    Calva, Edmundo; Calva, Juan J.; Wiesner, Magdalena; Fernández-Mora, Marcos; Puente, José L.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium strain 33676 was isolated in Mexico City, Mexico, from a patient with a systemic infection, and its complete genome sequence was determined using PacBio single-molecule real-time technology. Strain 33676 harbors an IncF plasmid carrying the extended-spectrum cephalosporin gene blaCMY-2 and a multidrug resistance IncA/C plasmid. PMID:26564044

  18. Transmission of an oxygen availability signal at the Salmonella enterica serovar Typhimurium fis promoter.

    PubMed

    Cameron, Andrew D S; Kröger, Carsten; Quinn, Heather J; Scally, Isobel K; Daly, Anne J; Kary, Stefani C; Dorman, Charles J

    2013-01-01

    The nucleoid-associated protein FIS is a global regulator of gene expression and chromosome structure in Escherichia coli and Salmonella enterica. Despite the importance of FIS for infection and intracellular invasion, very little is known about the regulation of S. enterica fis expression. Under standard laboratory growth conditions, fis is highly expressed during rapid growth but is then silenced as growth slows. However, if cells are cultured in non-aerated conditions, fis expression is sustained during stationary phase. This led us to test whether the redox-sensing transcription factors ArcA and FNR regulate S. enterica fis. Deletion of FNR had no detectable effect, whereas deletion of ArcA had the unexpected effect of further elevating fis expression in stationary phase. ArcA required RpoS for induction of fis expression, suggesting that ArcA indirectly affects fis expression. Other putative regulators were found to play diverse roles: FIS acted directly as an auto-repressor (as expected), whereas CRP had little direct effect on fis expression. Deleting regions of the fis promoter led to the discovery of a novel anaerobically-induced transcription start site (Pfis-2) upstream of the primary transcription start site (Pfis-1). Promoter truncation also revealed that the shortest functional fis promoter was incapable of sustained expression. Moreover, fis expression was observed to correlate directly with DNA supercoiling in non-aerated conditions. Thus, the full-length S. enterica fis promoter region may act as a topological switch that is sensitive to stress-induced duplex destabilisation and up-regulates expression in non-aerated conditions. PMID:24358360

  19. Compound(s) secreted by Lactobacillus casei strain Shirota YIT9029 irreversibly and reversibly impair the swimming motility of Helicobacter pylori and Salmonella enterica serovar Typhimurium, respectively.

    PubMed

    Le Moal, Vanessa Liévin; Fayol-Messaoudi, Domitille; Servin, Alain L

    2013-09-01

    We conducted experiments in order to examine whether the probiotic Lactobacillus casei strain Shirota YIT9029 (LcS) in vitro and in vivo antagonism of Helicobacter pylori and Salmonella, involves inhibition of the swimming motility of these pathogens. We report the irreversible inhibition of the swimming motility of H. pylori strain 1101 and reversible inhibition of Salmonella enterica serovar Typhimurium (S. Typhimurium) strain SL1344 by compound(s) secreted by LcS. In H. pylori 1101, irreversible inhibition results in the helical cells being progressively replaced by cells with 'c'-shaped and coccoid morphologies, accompanied by a loss of FlaA and FlaB flagellin expression. In S. Typhimurium SL1344, transient inhibition develops after membrane depolarization and without modification of expression of FliC flagellin. The inhibitory activity of strain LcS against both S. Typhimurium and H. pylori swimming motilities is linked with a small sized, heat-sensitive, and partially trypsin-sensitive, secreted compound(s), and needed the cooperation of the secreted membrane permeabilizing lactic acid metabolite. The inhibition of S. Typhimurium SL1344 swimming motility leads to delayed cell entry into human enterocyte-like Caco-2/TC7 cells and a strong decrease of cell entry into human mucus-secreting HT29-MTX cells. PMID:23873784

  20. The Stringent Response Regulator DksA Is Required for Salmonella enterica Serovar Typhimurium Growth in Minimal Medium, Motility, Biofilm Formation, and Intestinal Colonization

    PubMed Central

    Azriel, Shalhevet; Goren, Alina; Rahav, Galia

    2015-01-01

    Salmonella enterica serovar Typhimurium is a facultative intracellular human and animal bacterial pathogen posing a major threat to public health worldwide. Salmonella pathogenicity requires complex coordination of multiple physiological and virulence pathways. DksA is a conserved Gram-negative regulator that belongs to a distinct group of transcription factors that bind directly to the RNA polymerase secondary channel, potentiating the effect of the signaling molecule ppGpp during a stringent response. Here, we established that in S. Typhimurium, dksA is induced during the logarithmic phase and DksA is essential for growth in minimal defined medium and plays an important role in motility and biofilm formation. Furthermore, we determined that DksA positively regulates the Salmonella pathogenicity island 1 and motility-chemotaxis genes and is necessary for S. Typhimurium invasion of human epithelial cells and uptake by macrophages. In contrast, DksA was found to be dispensable for S. Typhimurium host cell adhesion. Finally, using the colitis mouse model, we found that dksA is spatially induced at the midcecum during the early stage of the infection and required for gastrointestinal colonization and systemic infection in vivo. Taken together, these data indicate that the ancestral stringent response regulator DksA coordinates various physiological and virulence S. Typhimurium programs and therefore is a key virulence regulator of Salmonella. PMID:26553464

  1. The Stringent Response Regulator DksA Is Required for Salmonella enterica Serovar Typhimurium Growth in Minimal Medium, Motility, Biofilm Formation, and Intestinal Colonization.

    PubMed

    Azriel, Shalhevet; Goren, Alina; Rahav, Galia; Gal-Mor, Ohad

    2016-01-01

    Salmonella enterica serovar Typhimurium is a facultative intracellular human and animal bacterial pathogen posing a major threat to public health worldwide. Salmonella pathogenicity requires complex coordination of multiple physiological and virulence pathways. DksA is a conserved Gram-negative regulator that belongs to a distinct group of transcription factors that bind directly to the RNA polymerase secondary channel, potentiating the effect of the signaling molecule ppGpp during a stringent response. Here, we established that in S. Typhimurium, dksA is induced during the logarithmic phase and DksA is essential for growth in minimal defined medium and plays an important role in motility and biofilm formation. Furthermore, we determined that DksA positively regulates the Salmonella pathogenicity island 1 and motility-chemotaxis genes and is necessary for S. Typhimurium invasion of human epithelial cells and uptake by macrophages. In contrast, DksA was found to be dispensable for S. Typhimurium host cell adhesion. Finally, using the colitis mouse model, we found that dksA is spatially induced at the midcecum during the early stage of the infection and required for gastrointestinal colonization and systemic infection in vivo. Taken together, these data indicate that the ancestral stringent response regulator DksA coordinates various physiological and virulence S. Typhimurium programs and therefore is a key virulence regulator of Salmonella. PMID:26553464

  2. ChIP-seq and transcriptome analysis of the OmpR regulon of Salmonella enterica serovars Typhi and Typhimurium reveals accessory genes implicated in host colonization

    PubMed Central

    Perkins, Timothy T; Davies, Mark R; Klemm, Elizabeth J; Rowley, Gary; Wileman, Thomas; James, Keith; Keane, Thomas; Maskell, Duncan; Hinton, Jay C D; Dougan, Gordon; Kingsley, Robert A

    2013-01-01

    Summary OmpR is a multifunctional DNA binding regulator with orthologues in many enteric bacteria that exhibits classical regulator activity as well as nucleoid-associated protein-like characteristics. In the enteric pathogen Salmonella enterica, using chromatin immunoprecipitation of OmpR:FLAG and nucleotide sequencing, 43 putative OmpR binding sites were identified in S. enterica serovar Typhi, 22 of which were associated with OmpR-regulated genes. Mutation of a sequence motif (TGTWACAW) that was associated with the putative OmpR binding sites abrogated binding of OmpR:6×His to the tviA upstream region. A core set of 31 orthologous genes were found to exhibit OmpR-dependent expression in both S. Typhi and S. Typhimurium. S. Typhimurium-encoded orthologues of two divergently transcribed OmpR-regulated operons (SL1068–71 and SL1066–67) had a putative OmpR binding site in the inter-operon region in S. Typhi, and were characterized using in vitro and in vivo assays. These operons are widely distributed within S. enterica but absent from the closely related Escherichia coli. SL1066 and SL1067 were required for growth on N-acetylmuramic acid as a sole carbon source. SL1068–71 exhibited sequence similarity to sialic acid uptake systems and contributed to colonization of the ileum and caecum in the streptomycin-pretreated mouse model of colitis. PMID:23190111

  3. Modulation of systemic and mucosal immunity against an inactivated vaccine of Newcastle disease virus by oral co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing chicken interleukin-18 and interferon-α

    PubMed Central

    RAHMAN, Md. Masudur; UYANGAA, Erdenebelig; HAN, Young Woo; HUR, Jin; PARK, Sang-Youel; LEE, John Hwa; KIM, Koanhoi; EO, Seong Kug

    2014-01-01

    Newcastle disease (ND) is a highly contagious disease of chickens causing significant economic losses worldwide. Due to limitations in the efficacy against currently circulating ND viruses, existing vaccination strategies require improvements, and incorporating immunomodulatory cytokines with existing vaccines might be a novel approach. Here, we investigated the systemic and mucosal immunomodulatory properties of oral co-administration of chicken interleukin-18 (chIL-18) and chicken interferon-α (chIFN-α) using attenuated Salmonella enterica serovar Typhimurium on an inactivated ND vaccine. Our results demonstrate that oral administration of S. enterica serovar Typhimurium expressing chIL-18 or chIFN-α provided enhanced systemic and mucosal immune responses, as determined by serum hemagglutination inhibition antibody and NDV Ag-specific IgG as well as NDV Ag-specific IgA in lung and duodenal lavages of chickens immunized with inactivated ND vaccine via the intramuscular or intranasal route. Notably, combined oral administration of S. enterica serovar Typhimurium expressing chIL-18 and chIFN-α significantly enhanced systemic and mucosal immunity in ND-vaccinated chickens, compared to single administration of S. enterica serovar Typhimurium expressing chIL-18 or chIFN-α. In addition, oral co-administration of S. enterica serovar Typhimurium expressing chIL-18 and chIFN-α provided enhanced NDV Ag-specific proliferation of peripheral blood mononuclear cells and Th1-biased cell-mediated immunity, compared to single administration of either construct. Therefore, our results provide valuable insight into the modulation of systemic and mucosal immunity by incorporation of immunomodulatory chIL-18 and chIFN-α using Salmonella vaccines into existing ND vaccines. PMID:25502364

  4. Transfer of Salmonella enterica Serovar Typhimurium from Beef to Tomato through Kitchen Equipment and the Efficacy of Intermediate Decontamination Procedures.

    PubMed

    Gkana, E; Lianou, A; Nychas, G-J E

    2016-07-01

    It is well established that a high percentage of foodborne illness is caused by failure of consumers to prepare food in a hygienic manner. Indeed, a common practice in households is to use the same kitchen equipment for both raw meat and fresh produce. Such a practice may lead to cross-contamination of fruits and vegetables, which are mainly consumed without further processing, with pathogenic microorganisms originating from raw meat. The present study was performed to examine the transfer of the pathogenic bacterium Salmonella enterica serovar Typhimurium from inoculated beef fillets to tomatoes via contact with high-density polyethylene (PE), stainless steel (SS), and wooden (WD) surfaces and through cutting with SS knives. Furthermore, the following decontamination procedures were applied: (i) rinsing with tap water, (ii) scrubbing with tap water and liquid dish detergent, and (iii) using a commercial antibacterial spray. When surfaces and knives that came into contact with contaminated beef fillets were not cleaned prior to handling tomatoes, the lowest level of pathogen transfer to tomatoes was observed through PE surfaces. All of the decontamination procedures applied were more effective on knives than on surfaces, while among the surface materials tested, WD surfaces were the most difficult to decontaminate, followed by PE and SS surfaces. Mechanical cleaning with tap water and detergent was more efficient in decontaminating WD surfaces than using commercial disinfectant spray, followed by rinsing only with water. Specifically, reductions of 2.07 and 1.09 log CFU/cm(2) were achieved by washing the WD surfaces with water and detergent and spraying the surfaces with an antibacterial product, respectively. Although the pathogen's populations on SS and PE surfaces, as well as on tomatoes, after both aforementioned treatments were under the detection limit, the surfaces were all positive after enrichment, and thus, the potential risk of cross-contamination cannot

  5. In Vitro Effects of Thymol-β-D-Glucopyranoside on Salmonella enterica Serovar Typhimurium and Escherichia coli K88.

    PubMed

    Levent, G; Harvey, R B; Ciftcioglu, G; Beier, R C; Genovese, K J; He, H L; Anderson, R C; Nisbet, D J

    2016-02-01

    Although thymol is bactericidal against many pathogens in vitro, its in vivo effectiveness against pathogens in the lower gastrointestinal tract is limited because of its rapid absorption in the proximal gut. Thymol-β-D-glucopyranoside (β-thymol), a conjugated form of thymol, can deliver thymol to the lower gastrointestinal tract and has shown antibacterial effects. In the present study, we examined the in vitro effects of β-thymol on Salmonella enterica serovar Typhimurium (ST) and Escherichia coli K88 (K88). We inoculated one-half strength Mueller-Hinton broth with 5.8 ± 0.09 log CFU/ml novobiocin- and naladixic acid-resistant (NN) ST (NVSL 95-1776) and 5.1 ± 0.09 log CFU ml(-1) NN-resistant K88, with or without porcine feces (0.1% [wt/vol]) (fecal incubations). The resultant bacterial suspensions were distributed under N2 to triplicate sets of tubes to achieve initial concentrations of 0, 3, 6, and 12 mM for ST treatments and 0, 3, 12, and 30 mM for K88 treatments. Samples were incubated at 39°C and then plated onto NN-containing brilliant green agar and NN-containing MacConkey agar; ST and K88 CFU concentrations were determined via 10-fold dilutions, and viable cell counts were performed at 0, 6, and 24 h. No differences in ST CFU counts were observed in β-thymol-treated tubes without the added porcine feces (i.e., pure culture) at 6 or 24 h. However, in tubes that contained fecal incubations, ST CFU counts were reduced (P < 0.05) from controls at 6 h in tubes treated with 6 and 12 mM β-thymol, whereas in tubes treated with 3, 6, and 12 mM β-thymol the CFU counts were reduced (P < 0.05) at 24 h. No differences were observed in K88 CFU counts in pure culture or in fecal incubations at 6 h, but K88 CFU counts were reduced (P < 0.05) in both pure and fecal incubations at 24 h. The results from this study demonstrate that β-thymol, in the presence of fecal suspensions, has anti-Salmonella and anti-E. coli effects, suggesting a role of

  6. Sensitization of Intracellular Salmonella enterica Serovar Typhimurium to Aminoglycosides In Vitro and In Vivo by a Host-Targeted Antimicrobial Agent

    PubMed Central

    Lo, Jung-Hsin; Kulp, Samuel K.; Chen, Ching-Shih

    2014-01-01

    Aminoglycosides exhibit relatively poor activity against intracellular Salmonella enterica serovar Typhimurium due to their low permeativity across eukaryotic cell membranes. Previously, we identified the unique ability of AR-12, a celecoxib-derived small-molecule agent, to eradicate intracellular Salmonella Typhimurium in macrophages by facilitating autophagosome formation and suppressing Akt kinase signaling. In light of this unique mode of antibacterial action, we investigated the ability of AR-12 to sensitize intracellular Salmonella to aminoglycosides in macrophages and in an animal model. The antibacterial activities of AR-12 combined with various aminoglycosides, including streptomycin, kanamycin, gentamicin, and amikacin, against intracellular S. Typhimurium in murine RAW264.7 macrophages were assessed. Cells were infected with S. Typhimurium followed by treatment with AR-12 or individual aminoglycosides or with combinations for 24 h. The in vivo efficacies of AR-12, alone or in combination with gentamicin or amikacin, were also assessed by treating S. Typhimurium-infected BALB/c mice daily for 14 consecutive days. Exposure of S. Typhimurium-infected RAW264.7 cells to a combination of AR-12 with individual aminoglycosides led to a reduction in bacterial survival (P < 0.05), both intracellular and extracellular, that was greater than that seen with the aminoglycosides alone. This sensitizing effect, however, was not associated with increased aminoglycoside penetration into bacteria or macrophages. Moreover, daily intraperitoneal injection of AR-12 at 0.1 mg/kg of body weight significantly increased the in vivo efficacy of gentamicin and amikacin in prolonging the survival of S. Typhimurium-infected mice. These findings indicate that the unique ability of AR-12 to enhance the in vivo efficacy of aminoglycosides might have translational potential for efforts to develop novel strategies for the treatment of salmonellosis. PMID:25267669

  7. Absence of Platelet Endothelial Cell Adhesion Molecule 1, PECAM-1/CD31, In Vivo Increases Resistance to Salmonella enterica Serovar Typhimurium in Mice

    PubMed Central

    Lovelace, Michael D.; Yap, May Lin; Yip, Jana; Muller, William; Wijburg, Odilia

    2013-01-01

    PECAM-1/CD31 is known to regulate inflammatory responses and exhibit pro- and anti-inflammatory functions. This study was designed to determine the functional role of PECAM-1 in susceptibility to murine primary in vivo infection with Salmonella enterica serovar Typhimurium and in in vitro inflammatory responses of peritoneal macrophages. Lectin profiling showed that cellular PECAM-1 and recombinant human PECAM-1-Ig chimera contain high levels of mannose sugars and N-acetylglucosamine. Consistent with this carbohydrate pattern, both recombinant human and murine PECAM-1-Ig chimeras were shown to bind S. Typhimurium in a dose-dependent manner in vitro. Using oral and fecal-oral transmission models of S. Typhimurium SL1344 infection, PECAM-1−/− mice were found to be more resistant to S. Typhimurium infection than wild-type (WT) C57BL/6 mice. While fecal shedding of S. Typhimurium was comparable in wild-type and PECAM-1−/− mice, the PECAM-1-deficient mice had lower bacterial loads in systemic organs such as liver, spleen, and mesenteric lymph nodes than WT mice, suggesting that extraintestinal dissemination was reduced in the absence of PECAM-1. This reduced bacterial load correlated with reduced tumor necrosis factor (TNF), interleukin-6 (IL-6), and monocyte chemoattractant protein (MCP) levels in sera of PECAM-1−/− mice. Following in vitro stimulation of macrophages with either whole S. Typhimurium, lipopolysaccharide (LPS) (Toll-like receptor 4 [TLR4] ligand), or poly(I·C) (TLR3 ligand), production of TNF and IL-6 by PECAM-1−/− macrophages was reduced. Together, these results suggest that PECAM-1 may have multiple functions in resistance to infection with S. Typhimurium, including binding to host cells, extraintestinal spread to deeper tissues, and regulation of inflammatory cytokine production by infected macrophages. PMID:23509149

  8. Assessment of 2 Salmonella enterica serovar Typhimurium-based vaccines against necrotic enteritis in reducing colonization of chickens by Salmonella serovars of different serogroups.

    PubMed

    Jiang, Yanfen; Kulkarni, Raveendra R; Parreira, Valeria R; Poppe, Cornelius; Roland, Kenneth L; Prescott, John F

    2010-10-01

    This study assessed the protective efficacy of oral vaccination with 2 experimental attenuated Salmonella Typhimurium-vectored vaccines for necrotic enteritis in protecting chickens against intestinal colonization by common serovars of Salmonella belonging to the 4 major serogroups affecting chickens. Birds were vaccinated orally with 1 × 10⁸ colony-forming units (CFU) of 1 of the vaccine strains χ9241 and χ9352, which express a plasmid-encoded partial recombinant hypothetical protein gene (tHP) of Clostridium perfringens, at days 1 and 7 of age, and then were challenged at 14 d of age with 10⁶ CFU of Salmonella serovars Anatum, Enteritidis, Heidelberg, Kentucky, or Typhimurium (representative serovars of serogroups B, C, D, and E). Birds were necropsied at 4 wk of age, and samples were collected to determine reduction in tissue and intestinal colonization. The chickens vaccinated with χ9241-tHP showed reduced colonization by Salmonella Enteritidis (serogroup D) and by Salmonella Heidelberg and Salmonella Typhimurium (serogroup B) compared with the control birds. No reduction in colonization was observed in the chickens vaccinated with χ9352-tHP. There was an association between the efficacy of these vaccine strains in protecting against necrotic enteritis, assessed on an earlier occasion, and their efficacy in protecting against Salmonella colonization. Thus, the choice of an attenuated Salmonella Typhimurium vaccine vector for delivery of heterologous antigens to chickens should be based partly on the vaccine's value in protecting against colonization by serovars within serogroups B and D. Such vectors would have the additional benefit of reducing colonization of important Salmonella serovars. PMID:21197226

  9. Enhancement of Host Immune Responses by Oral Vaccination to Salmonella enterica serovar Typhimurium Harboring Both FliC and FljB Flagella

    PubMed Central

    Eom, Jeong Seon; Seok Kim, Jin; Im Jang, Jung; Kim, Bae-Hoon; Young Yoo, So; Hyeon Choi, Ji; Bang, Iel-Soo; Lee, In Soo; Keun Park, Yong

    2013-01-01

    Flagellin, the structural component of the flagellar filament in various motile bacteria, can contribute to the activation of NF-κB and proinflammatory cytokine expression during the innate immune response in host cells. Thus, flagellin proteins represent a particularly attractive target for the development of vaccine candidates. In this study, we investigated the immune response by increasing the flagella number in the iacP mutant strain and the adjuvant activity of the flagellin component FljB of Salmonella enterica serovar Typhimurium. We found that the iacP mutant strain expresses two flagellin proteins (FliC and FljB), which result in increased NF-κB-dependent gene expression in bone marrow derived macrophages. Using an oral immunization mouse model, we observed that the administration of a live attenuated S. typhimurium BRD509 strain expressing the FliC and FljB flagellins induced significantly enhanced flagellin-specific IgG responses in the systemic compartment. The mice immunized with the recombinant attenuated S. typhimurium strain that has two types of flagella were protected from lethal challenge with the Salmonella SL1344 strain. These results indicate that overexpression of flagella in the iacP mutant strain enhance the induction of an antigen-specific immune responses in macrophage cell, and both the FliC and FljB flagellar filament proteins-producing S. typhimurium can induce protective immune responses against salmonellosis. PMID:24069357

  10. Association of a Protective Monoclonal IgA with the O Antigen of Salmonella enterica Serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity

    PubMed Central

    Forbes, Stephen J.; Martinelli, Daniel; Hsieh, Chyongere; Ault, Jeffrey G.; Marko, Michael; Mannella, Carmen A.

    2012-01-01

    Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as the Salmonella pathogenicity island 1 (SPI-1) type 3 secretion system (T3SS). By a mechanism that remains poorly understood, entry of S. Typhimurium into epithelial cells is inhibited by Sal4, a monoclonal, polymeric IgA antibody that binds an immunodominant epitope within the O-antigen (O-Ag) component of lipopolysaccharide. In this study, we investigated how the binding of Sal4 to the surface of S. Typhimurium influences T3SS activity, bacterial energetics, and outer membrane integrity. We found that Sal4 treatment impaired T3SS-mediated translocon formation and attenuated the delivery of tagged effector proteins into epithelial cells. Sal4 treatment coincided with a partial reduction in membrane energetics and intracellular ATP levels, possibly explaining the impairment in T3SS activity. Sal4's effects on bacterial secretion and energetics occurred concurrently with an increase in O-Ag levels in culture supernatants, alterations in outer membrane permeability, and changes in surface ultrastructure, as revealed by transmission electron microscopy and cryo-electron microscopy. We propose that Sal4, by virtue of its ability to bind and cross-link the O-Ag, induces a form of outer membrane stress that compromises the integrity of the S. Typhimurium cell envelope and temporarily renders the bacterium avirulent. PMID:22473607

  11. Bacteriophage-encoded type III effectors in Salmonella enterica subspecies 1 serovar Typhimurium.

    PubMed

    Ehrbar, Kristin; Hardt, Wolf-Dietrich

    2005-01-01

    Salmonella spp. are Gram-negative bacteria which cause infections ranging from mild, self-limiting enterocolitis to systemic (typhoid) disease. Recent work has established that the genetic makeup varies considerably between different Salmonella strains. Phages play an important role in this diversity. In fact, Salmonella has emerged as a prime example for the involvement of virulence factor encoding phages in the emergence of new epidemic strains. Among other virulence factors, Salmonella enterica utilizes two specialized protein secretion systems termed type III secretion systems (TTSS) to deliver effector proteins into host cells which manipulate host cell signaling cascades. These two TTSS and several effectors are encoded within Salmonella pathogenicity islands 1 and 2. Some effectors including SopE, SspH1, SseI and SopE2 are encoded by phages or phage remnants. These phage-encoded effectors seem to be transferred between different Salmonella strains. They have attracted much interest because they might contribute to the evolution of Salmonella spp. Here we will focus on SopEPhi which encodes the SPI-1 effector SopE. It provides an excellent example to illustrate how horizontally transferred effector proteins are integrated into the complex regulatory network of a TTSS in a recipient bacterium. Additional data supporting the hypothesis are presented. This is a prerequisite to allow optimization of the bacterium host cell interaction by reassortment of the phage-encoded effector protein repertoire. PMID:15567133

  12. Igg Subclasses Targeting the Flagella of Salmonella enterica Serovar Typhimurium Can Mediate Phagocytosis and Bacterial Killing

    PubMed Central

    Goh, Yun Shan; Armour, Kathryn L; Clark, Michael R; Grant, Andrew J; Mastroeni, Pietro

    2016-01-01

    Invasive non-typhoidal Salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. Multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. Flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. We examined the effect of targeting flagella with different classes of IgG on the interaction between Salmonella Typhimurium and a human phagocyte-like cell line, THP-1. We tagged the FliC flagellar protein with a foreign CD52 mimotope (TSSPSAD) and bacteria were opsonized with a panel of humanised CD52 antibodies with the same antigen-binding V-region, but different constant regions. We found that IgG binding to flagella increases bacterial phagocytosis and reduces viable intracellular bacterial numbers. Opsonisation with IgG3, followed by IgG1, IgG4, and IgG2, resulted in the highest level of bacterial uptake and in the highest reduction in the intracellular load of viable bacteria. Taken together, our data provide proof-of-principle evidence that targeting flagella with antibodies can increase the antibacterial function of host cells, with IgG3 being the most potent subclass. These data will assist the rational design of urgently needed, optimised vaccines against iNTS disease. PMID:27366588

  13. Retinoic acid decreases the severity of Salmonella enterica serovar Typhimurium mediated gastroenteritis in a mouse model.

    PubMed

    Sinha, Ritam; Howlader, Debaki Ranjan; Mukherjee, Priyadarshini; Rai, Sulabh; Nag, Dhrubajyoti; Koley, Hemanta

    2016-07-01

    Gastroenteritis is a global burden; it's the major cause of morbidity and mortality both in adults and children of developing countries. Salmonella is one of the leading causes of bacteria-mediated gastroenteritis and due to its increasing multidrug antibiotic resistance; Salmonella-mediated gastroenteritis is difficult to control. Retinoic acid, the biologically active agent of vitamin A has an anti-inflammatory effect on experimental colitis. In this study we have shown All trans retinoic acid (ATRA) treatment down regulates Salmonella-mediated colitis in a murine model. Macroscopic signs of inflammation such as decrease in body weight and cecum weight, shorter length of proximal colon and pathological score of colitis were observed less in ATRA treated mice than in a vehicle control group. ATRA treatment not only reduced pro-inflammatory cytokine responses, such as TNF-α, IL-6, IL-1β, IFN-γ and IL-17 production but also increased IL-10 response in the supernatant of intestinal tissue. Results also suggested that ATRA treatment enhances the number of FoxP3-expressing T regulatory cells in MLN and also decreases bacterial load in systemic organs. We concluded that ATRA treatment indeed reduces Salmonella Typhimurium-mediated gastroenteritis in mice, suggesting it could be an important part of an alternative therapeutic approach to combat the disease. PMID:26858186

  14. Characterization of Novel Factors Involved in Swimming and Swarming Motility in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Deditius, Julia Andrea; Kühne, Caroline; Frahm, Michael; Rohde, Manfred; Weiß, Siegfried; Erhardt, Marc

    2015-01-01

    Salmonella enterica utilizes flagellar motility to swim through liquid environments and on surfaces. The biosynthesis of the flagellum is regulated on various levels, including transcriptional and posttranscriptional mechanisms. Here, we investigated the motility phenotype of 24 selected single gene deletions that were previously described to display swimming and swarming motility effects. Mutations in flgE, fliH, ydiV, rfaG, yjcC, STM1267 and STM3363 showed an altered motility phenotype. Deletions of flgE and fliH displayed a non-motile phenotype in both swimming and swarming motility assays as expected. The deletions of STM1267, STM3363, ydiV, rfaG and yjcC were further analyzed in detail for flagellar and fimbrial gene expression and filament formation. A ΔydiV mutant showed increased swimming motility, but a decrease in swarming motility, which coincided with derepression of curli fimbriae. A deletion of yjcC, encoding for an EAL domain-containing protein, increased swimming motility independent on flagellar gene expression. A ΔSTM1267 mutant displayed a hypermotile phenotype on swarm agar plates and was found to have increased numbers of flagella. In contrast, a knockout of STM3363 did also display an increase in swarming motility, but did not alter flagella numbers. Finally, a deletion of the LPS biosynthesis-related protein RfaG reduced swimming and swarming motility, associated with a decrease in transcription from flagellar class II and class III promoters and a lack of flagellar filaments. PMID:26267246

  15. Coordinated Regulation of Virulence during Systemic Infection of Salmonella enterica serovar Typhimurium

    SciTech Connect

    Yoon, Hyunjin; McDermott, Jason E.; Porwollik, Steffen; Mcclelland, Michael; Heffron, Fred

    2009-02-20

    Salmonella must respond to a myriad of environmental cues during infection of a mouse and express specific subsets of genes in a temporal and spatial manner to subvert the host defense mechanisms but these regulatory pathways are poorly established. To unravel how micro-environmental signals are processed and integrated into coordinated action, we constructed in-frame non-polar deletions of 84 regulators inferred to play a role in Salmonella typhimurium virulence and tested them in three virulence assays (intraperitoneal (i.p.), and intragastric (i.g.) infection in BALB/c mice, and persistence in SvJ129 mice). Overall 36 regulators were identified that were less virulent in at least one assay, and of those, 15 regulators were required for systemic mouse infection in an acute infection model. As a first step towards understanding the interplay between a pathogen and its host from a systems biology standpoint we focused on these 15 genes. Transcriptional profiles were obtained for each of these 15 regulators from strains grown under four different environmental conditions. These results as well as publicly available transcriptional profiles were analyzed using both network inference and cluster analysis algorithms. The analysis predicts a regulatory network in which all 15 regulators control a specific set of genes necessary for Salmonella to cause systemic infection. We tested the regulatory model by expressing a subset of the regulators in trans and monitoring transcription of 7 known virulence factors located within Salmonella pathogenicity island 2 (SPI-2). These experiments validated the regulatory model and showed that, for these 7 genes, the response regulator SsrB and the marR type regulator SlyA co-regulate in a regulatory cascade by integrating multiple signals.

  16. Poultry Body Temperature Contributes to Invasion Control through Reduced Expression of Salmonella Pathogenicity Island 1 Genes in Salmonella enterica Serovars Typhimurium and Enteritidis

    PubMed Central

    Petri, Nicholas; Daron, Caitlyn; Pereira, Rafaela; Mendoza, Mary; Hassan, Hosni M.; Koci, Matthew D.

    2015-01-01

    Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence. PMID:26386070

  17. Comparative proteomic analysis of Salmonella enterica serovar Typhimurium ppGpp-deficient mutant to identify a novel virulence protein required for intracellular survival in macrophages

    PubMed Central

    2010-01-01

    Background The global ppGpp-mediated stringent response in pathogenic bacteria plays an important role in the pathogenesis of bacterial infections. In Salmonella enterica serovar Typhimurium (S. Typhimurium), several genes, including virulence genes, are regulated by ppGpp when bacteria are under the stringent response. To understand the control of virulence genes by ppGpp in S. Typhimurium, agarose 2-dimensional electrophoresis (2-DE) combined with mass spectrometry was used and a comprehensive 2-DE reference map of amino acid-starved S. Typhimurium strain SH100, a derivative of ATCC 14028, was established. Results Of the 366 examined spots, 269 proteins were successfully identified. The comparative analysis of the wild-type and ppGpp0 mutant strains revealed 55 proteins, the expression patterns of which were affected by ppGpp. Using a mouse infection model, we further identified a novel virulence-associated factor, STM3169, from the ppGpp-regulated and Salmonella-specific proteins. In addition, Salmonella strains carrying mutations in the gene encoding STM3169 showed growth defects and impaired growth within macrophage-like RAW264.7 cells. Furthermore, we found that expression of stm3169 was controlled by ppGpp and SsrB, a response regulator of the two-component system located on Salmonella pathogenicity island 2. Conclusions A proteomic approach using a 2-DE reference map can prove a powerful tool for analyzing virulence factors and the regulatory network involved in Salmonella pathogenesis. Our results also provide evidence of a global response mediated by ppGpp in S. enterica. PMID:21176126

  18. β-1,3/1,6-Glucan alleviated intestinal mucosal barrier impairment of broiler chickens challenged with Salmonella enterica serovar Typhimurium.

    PubMed

    Shao, Yujing; Guo, Yuming; Wang, Zhong

    2013-07-01

    This study investigated the protective effect of β-1,3/1,6-glucan on gut morphology, intestinal epithelial tight junctions, and bacterial translocation of broiler chickens challenged with Salmonella enterica serovar Typhimurium. Ninety Salmonella-free Arbor Acre male broiler chickens were randomly divided into 3 groups: negative control group (NC), Salmonella Typhimurium-infected positive group (PC), and the Salmonella Typhimurium-infected group with dietary 100 mg/kg of β-1,3/1,6-glucan supplementation (T) to determine the effect of β-1,3/1,6-glucan on intestinal barrier function. Salmonella Typhimurium challenge alone significantly decreased villus height (P < 0.001), villus height/crypt depth ratio (P < 0.05), and the number of goblet cells (P < 0.001) in the jejunum at 14 d postinfection (dpi), but significantly increased the number of intestinal secretory IgA (sIgA)-expressing cells at 14 dpi (P < 0.01) and total sIgA levels in the jejunum at 7 (P < 0.05) and 14 dpi (P < 0.01) compared with the unchallenged birds (NC). Dietary β-1,3/1,6-glucan supplementation not only significantly increased villus height, villus height/crypt depth ratio, and the number of goblet cells (P < 0.01), but also increased the number of sIgA-expressing cells (P < 0.05) and sIgA content in the jejunum at 14 dpi (P < 0.01) in birds challenged with Salmonella Typhimurium in comparison with Salmonella Typhimurium challenge alone. β-1,3/1,6-Glucan addition had significant inhibitory effects (P < 0.05) on cecal Salmonella colonization levels and liver Salmonella invasion of the Salmonella Typhimurium-infected birds compared with the PC group. Intestinal tight junction proteins claudin-1, claudin-4, and occludin mRNA expression in the jejunum at 14 dpi was significantly decreased by Salmonella Typhimurium challenge alone (P < 0.01) compared with that of the NC group, whereas β-1,3/1,6-glucan supplementation significantly increased claudin-1 and occludin mRNA expression (P < 0.01) at

  19. Regulation of the Two-Component Regulator CpxR on Aminoglycosides and β-lactams Resistance in Salmonella enterica serovar Typhimurium

    PubMed Central

    Huang, Hui; Sun, Yawei; Yuan, Li; Pan, Yushan; Gao, Yanlin; Ma, Caihui; Hu, Gongzheng

    2016-01-01

    The two-component signal transduction system CpxAR is especially widespread in Gram-negative bacteria. It has been reported that CpxAR contributes to the multidrug resistance (MDR) in Escherichia coli. CpxR is a response regulator in the two-component CpxAR system. The aim of this study was to explore the role of cpxR in the MDR of S. enterica serovar Typhimurium. The minimal inhibitory concentrations (MICs) of various antibiotics commonly used in veterinary medicine for strains JS (a multidrug-susceptible standard strain of S. enterica serovar Typhimurium), JSΔcpxR, JSΔcpxR/pcpxR, JSΔcpxR/pcpxR*, JSΔcpxRΔacrB, JSΔcpxRΔacrB/pcpxR, JSΔcpxRΔacrB/pcpxR*, 9 S. enterica serovar Typhimurium isolates (SH1–9), and SH1–9ΔcpxR were determined by the 2-fold broth microdilution method. The relative mRNA expression levels of ompF, ompC, ompW, ompD, tolC, acrB, acrD, acrF, mdtA, marA, and soxS in strains JS, JSΔcpxR, and JSΔcpxR/pcpxR were detected by real-time PCR. The results showed 2- to 4-fold decreases in the MICs of amikacin (AMK), gentamycin (GEN), apramycin (APR), neomycin (NEO), ceftriaxone (CRO), ceftiofur (CEF), and cefquinome (CEQ) for strain JSΔcpxR, as compared to those for the parental strain JS. Likewise, SH1–9ΔcpxR were found to have 2- to 8-fold reduction in resistance to the above antibiotics, except for NEO, as compared to their parental strains SH1–9. Furthermore, 2- to 4-fold further decreases in the MICs of AMK, GEN, APR, and CEF for strain JSΔcpxRΔacrB were observed, as compared to those for strain JSΔacrB. In addition, CpxR overproduction in strain JSΔcpxR led to significant decreases in the mRNA expression levels of ompF, ompC, ompW, ompD, tolC, acrB, marA, and soxS, and significant increases in those of stm3031 and stm1530. Notably, after all strains were induced simultaneously by GEN to the 15th passage at subinhibitory concentrations, strain JSΔcpxR/pcpxR showed significant increases in mRNA expression levels of the efflux

  20. Fluorescence-based thermal shift data on multidrug regulator AcrR from Salmonella enterica subsp. entrica serovar Typhimurium str. LT2.

    PubMed

    Manjasetty, Babu A; Halavaty, Andrei S; Luan, Chi-Hao; Osipiuk, Jerzy; Mulligan, Rory; Kwon, Keehwan; Anderson, Wayne F; Joachimiak, Andrzej

    2016-06-01

    The fluorescence-based thermal shift (FTS) data presented here include Table S1 and Fig. S1, and are supplemental to our original research article describing detailed structural, FTS, and fluorescence polarization analyses of the Salmonella enterica subsp. entrica serovar Typhimurium str. LT2 multidrug transcriptional regulator AcrR (StAcrR) (doi:10.1016/j.jsb.2016.01.008) (Manjasetty et al., 2015 [1]). Table S1 contains chemical formulas, a Chemical Abstracts Service (CAS) Registry Number (CAS no.), FTS rank (a ligand with the highest rank) has the largest difference in the melting temperature (ΔT m), and uses as drug molecules against various pathological conditions of sixteen small-molecule ligands that increase thermal stability of StAcrR. Thermal stability of human enolase 1, a negative control protein, was not affected in the presence of various concentrations of the top six StAcrR binders (Fig. S1). PMID:27054155

  1. Model-driven discovery of synergistic inhibitors against E. coli and S. enterica serovar Typhimurium targeting a novel synthetic lethal pair, aldA and prpC

    PubMed Central

    Aziz, Ramy K.; Khaw, Valerie L.; Monk, Jonathan M.; Brunk, Elizabeth; Lewis, Robert; Loh, Suh I.; Mishra, Arti; Nagle, Amrita A.; Satyanarayana, Chitkala; Dhakshinamoorthy, Saravanakumar; Luche, Michele; Kitchen, Douglas B.; Andrews, Kathleen A.; Palsson, Bernhard Ø.; Charusanti, Pep

    2015-01-01

    Mathematical models of biochemical networks form a cornerstone of bacterial systems biology. Inconsistencies between simulation output and experimental data point to gaps in knowledge about the fundamental biology of the organism. One such inconsistency centers on the gene aldA in Escherichia coli: it is essential in a computational model of E. coli metabolism, but experimentally it is not. Here, we reconcile this disparity by providing evidence that aldA and prpC form a synthetic lethal pair, as the double knockout could only be created through complementation with a plasmid-borne copy of aldA. Moreover, virtual and biological screening against the two proteins led to a set of compounds that inhibited the growth of E. coli and Salmonella enterica serovar Typhimurium synergistically at 100–200 μM individual concentrations. These results highlight the power of metabolic models to drive basic biological discovery and their potential use to discover new combination antibiotics. PMID:26441892

  2. Identification of Two Laminin-Binding Fimbriae, the Type 1 Fimbria of Salmonella enterica Serovar Typhimurium and the G Fimbria of Escherichia coli, as Plasminogen Receptors

    PubMed Central

    Kukkonen, Maini; Saarela, Sirkku; Lähteenmäki, Kaarina; Hynönen, Ulla; Westerlund-Wikström, Benita; Rhen, Mikael; Korhonen, Timo K.

    1998-01-01

    Escherichia coli strains carrying recombinant plasmids encoding either the type 1 fimbria of Salmonella enterica serovar Typhimurium or the G fimbria of E. coli exhibited binding of human 125I-Glu-plasminogen and enhanced the tissue-type plasminogen activator-catalyzed conversion of plasminogen to plasmin. Purified type 1 or G fimbriae similarly bound plasminogen and enhanced its activation. The binding of plasminogen did not involve the characteristic carbohydrate-binding property of the fimbriae but was inhibited at low concentrations by the lysine analog ɛ-aminocaproic acid. Because these fimbrial types bind to laminin of basement membranes (M. Kukkonen et al., Mol. Microbiol. 7:229–237, 1993; S. Saarela et al., Infect. Immun. 64:2857–2860, 1996), the results demonstrate a structural unity in the creation and targeting of bacterium-bound proteolytic plasmin activity to basement membranes. PMID:9746604

  3. Salmonella enterica Serovar Typhimurium Requires the Lpf, Pef, and Tafi Fimbriae for Biofilm Formation on HEp-2 Tissue Culture Cells and Chicken Intestinal Epithelium

    PubMed Central

    Ledeboer, Nathan A.; Frye, Jonathan G.; McClelland, Michael; Jones, Bradley D.

    2006-01-01

    Recent work has demonstrated that Salmonella enterica serovar Typhimurium forms biofilms on HEp-2 tissue culture cells in a type 1 fimbria-dependent manner. To investigate how biofilm growth of HEp-2 tissue culture cells affects gene expression in Salmonella, we compared global gene expression during planktonic growth and biofilm growth. Microarray results indicated that the transcription of ∼100 genes was substantially altered by growth in a biofilm. These genes encode proteins with a wide range of functions, including antibiotic resistance, central metabolism, conjugation, intracellular survival, membrane transport, regulation, and fimbrial biosynthesis. The identification of five fimbrial gene clusters was of particular interest, as we have demonstrated that type 1 fimbriae are required for biofilm formation on HEp-2 cells and murine intestinal epithelium. Mutations in each of these fimbriae were constructed in S. enterica serovar Typhimurium strain BJ2710, and the mutants were found to have various biofilm phenotypes on plastic, HEp-2 cells, and chicken intestinal tissue. The pef and csg mutants were defective for biofilm formation on each of the three surfaces tested, while the lpf mutant exhibited a complete loss of the ability to form a biofilm on chicken intestinal tissue but only an intermediate loss of the ability to form a biofilm on tissue culture cells and plastic surfaces. The bcf mutant displayed increased biofilm formation on both HEp-2 cells and chicken intestinal epithelium, while the sth mutant had no detectable biofilm defects. In all instances, the mutants could be restored to a wild-type phenotype by a plasmid carrying the functional genes. This is the first work to identify the genomic responses of Salmonella to biofilm formation on host cells, and this work highlights the importance of fimbriae in adhering to and adapting to a eukaryotic cell surface. An understanding of these interactions is likely to provide new insights for intervention

  4. Multidrug-resistant Salmonella enterica Serovar Typhimurium Monophasic Variant 4,12:i:- Isolated from Asymptomatic Wildlife in a Catalonian Wildlife Rehabilitation Center, Spain.

    PubMed

    Molina-López, Rafael A; Vidal, Anna; Obón, Elena; Martín, Marga; Darwich, Laila

    2015-07-01

    Wildlife can act as long-term asymptomatic reservoirs for zoonotic bacteria, such as Salmonella. The prevalence and antimicrobial-susceptibility profiles of Salmonella spp. were assessed in 263 cases in wildlife from 22 animal orders from a wildlife rehabilitation center in Catalonia (NE Spain), September 2013-May 2014. Eleven of 263 tested animals were positive for Salmonella spp., representing an overall prevalence of 4.2%. Prevalences by taxonomic categories were 2% in mammals, 4.7% in birds, and 4.5% in reptiles. By species, one each of European hedgehog (Erinaceus europeus; from a sample of n = 26), Eurasian Eagle Owl (Bubo bubo; n = 2), Barn Owl (Tyto alba; n = 3), Tawny Owl (Strix aluco; n = 20), Egyptian Vulture (Neophron percnopterus; n = 1), Griffon Vulture (Gyps fulvus; n = 1), and Hoopoe (Upupa epops; n = 2), and two each Common Kestrels (Falco tinnunculus; n = 16) and pond sliders (Trachemys scripta; n = 25) were positive for Salmonella. By serotyping, seven of eleven isolates were classified as S. enterica subsp. enterica serovar Typhimurium, and five of seven belonged to the monophasic variant 4,12:i:-. All the monophasic variants were isolated from birds (4/5 in raptors) and showed a multidrug-resistance (MDR) profile to at least ampicillin, streptomycin, sulfonamide, and tetracycline (R-type ASSuT), and up to 12 antibiotics. The large proportion of S. Typhimurium monophasic MDR strains detected in wildlife never treated with antibiotics, especially in raptors, adds more complexity to the epidemiologic control of one of the most frequent serovars involved in human and livestock infection. PMID:25973627

  5. Salmonella enterica Serovar Typhimurium Colonizing the Lumen of the Chicken Intestine Grows Slowly and Upregulates a Unique Set of Virulence and Metabolism Genes▿

    PubMed Central

    Harvey, P. C.; Watson, M.; Hulme, S.; Jones, M. A.; Lovell, M.; Berchieri, A.; Young, J.; Bumstead, N.; Barrow, P.

    2011-01-01

    The pattern of global gene expression in Salmonella enterica serovar Typhimurium bacteria harvested from the chicken intestinal lumen (cecum) was compared with that of a late-log-phase LB broth culture using a whole-genome microarray. Levels of transcription, translation, and cell division in vivo were lower than those in vitro. S. Typhimurium appeared to be using carbon sources, such as propionate, 1,2-propanediol, and ethanolamine, in addition to melibiose and ascorbate, the latter possibly transformed to d-xylulose. Amino acid starvation appeared to be a factor during colonization. Bacteria in the lumen were non- or weakly motile and nonchemotactic but showed upregulation of a number of fimbrial and Salmonella pathogenicity island 3 (SPI-3) and 5 genes, suggesting a close physical association with the host during colonization. S. Typhimurium bacteria harvested from the cecal mucosa showed an expression profile similar to that of bacteria from the intestinal lumen, except that levels of transcription, translation, and cell division were higher and glucose may also have been used as a carbon source. PMID:21768276

  6. Delineating Community Outbreaks of Salmonella enterica Serovar Typhimurium by Use of Whole-Genome Sequencing: Insights into Genomic Variability within an Outbreak

    PubMed Central

    Octavia, Sophie; Wang, Qinning; Tanaka, Mark M.; Kaur, Sandeep; Sintchenko, Vitali

    2015-01-01

    Whole-genome next-generation sequencing (NGS) was used to retrospectively examine 57 isolates from five epidemiologically confirmed community outbreaks (numbered 1 to 5) caused by Salmonella enterica serovar Typhimurium phage type DT170. Most of the human and environmental isolates confirmed epidemiologically to be involved in the outbreaks were either genomically identical or differed by one or two single nucleotide polymorphisms (SNPs), with the exception of those in outbreak 1. The isolates from outbreak 1 differed by up to 12 SNPs, which suggests that the food source of the outbreak was contaminated with more than one strain while each of the other four outbreaks was caused by a single strain. In addition, NGS analysis ruled in isolates that were initially not considered to be linked with the outbreak, which increased the total outbreak size by 107%. The mutation process was modeled by using known mutation rates to derive a cutoff value for the number of SNP difference to determine whether or not a case was part of an outbreak. For an outbreak with less than 1 month of ex vivo/in vivo evolution time, the maximum number of SNP differences between isolates is two or four using the lowest or highest mutation rate, respectively. NGS of S. Typhimurium significantly increases the resolution of investigations of community outbreaks. It can also inform a more targeted public health response by providing important supplementary evidence that cases of disease are or are not associated with food-borne outbreaks of S. Typhimurium. PMID:25609719

  7. Toll-Like Receptor Activation by Generalized Modules for Membrane Antigens from Lipid A Mutants of Salmonella enterica Serovars Typhimurium and Enteritidis

    PubMed Central

    Rossi, Omar; Caboni, Mariaelena; Negrea, Aurel; Necchi, Francesca; Alfini, Renzo; Micoli, Francesca; Saul, Allan; MacLennan, Calman A.

    2016-01-01

    Invasive nontyphoidal Salmonella (iNTS) disease is a neglected disease with high mortality in children and HIV-positive individuals in sub-Saharan Africa, caused primarily by Africa-specific strains of Salmonella enterica serovars Typhimurium and Enteritidis. A vaccine using GMMA (generalized modules for membrane antigens) from S. Typhimurium and S. Enteritidis containing lipid A modifications to reduce potential in vivo reactogenicity is under development. GMMA with penta-acylated lipid A showed the greatest reduction in the level of cytokine release from human peripheral blood monocytes from that for GMMA with wild-type lipid A. Deletion of the lipid A modification genes msbB and pagP was required to achieve pure penta-acylation. Interestingly, ΔmsbB ΔpagP GMMA from S. Enteritidis had a slightly higher stimulatory potential than those from S. Typhimurium, a finding consistent with the higher lipopolysaccharide (LPS) content and Toll-like receptor 2 (TLR2) stimulatory potential of the former. Also, TLR5 ligand flagellin was found in Salmonella GMMA. No relevant contribution to the stimulatory potential of GMMA was detected even when the flagellin protein FliC from S. Typhimurium was added at a concentration as high as 10% of total protein, suggesting that flagellin impurities are not a major factor for GMMA-mediated immune stimulation. Overall, the stimulatory potential of S. Typhimurium and S. Enteritidis ΔmsbB ΔpagP GMMA was close to that of Shigella sonnei GMMA, which are currently in phase I clinical trials. PMID:26865597

  8. Extensive genetic variability linked to IS26 insertions in the fljB promoter region of atypical monophasic variants of Salmonella enterica serovar Typhimurium.

    PubMed

    Boland, Cécile; Bertrand, Sophie; Mattheus, Wesley; Dierick, Katelijne; Jasson, Vicky; Rosseel, Toon; Van Borm, Steven; Mahillon, Jacques; Wattiau, Pierre

    2015-05-01

    Fifty-nine monophasic Salmonella enterica serovar Typhimurium isolates, collected in Belgium during the period from 2008 to 2011, have been serotyped as 4,[5]:i:- and shown to harbor an fljB coding sequence. The genetic differences between these strains and phenotypically biphasic Salmonella Typhimurium were analyzed through PCR and DNA sequencing. Genetic alterations in the fljB promoter region affecting expression of the phase 2 flagellin were observed in 53 isolates. Other genetic events in the invertible region carrying the fljB promoter were observed in 2 isolates. For the remaining 4 isolates, no molecular differences with a reference biphasic Salmonella Typhimurium strain could be observed. Next-generation sequencing of one representative isolate affected in the fljB promoter region revealed a 26-kb IS26 composite transposon insertion along with a local genomic rearrangement. Several other IS26 element-mediated alterations of this genomic region were observed. This group of monophasic Salmonella Typhimurium isolates was genetically heterogeneous, as revealed by multilocus variable-number tandem-repeat analysis (MLVA), PCR, and sequencing. Pigs and pork represented a major source of such monophasic isolates in Belgium, as reported in other countries. Three out of 5 isolates of human origin presented genetic profiles identical to those of food isolates, demonstrating the pathogenic potential of the newly characterized variants and potential dissemination along the food chain. This study highlighted the key role played by IS26 insertions in the loss of phase 2 flagellin expression and the subsequent generation of multiple monophasic variant lineages from biphasic Salmonella Typhimurium ancestors. PMID:25724958

  9. wksl3, a New Biocontrol Agent for Salmonella enterica Serovars Enteritidis and Typhimurium in Foods: Characterization, Application, Sequence Analysis, and Oral Acute Toxicity Study

    PubMed Central

    Kang, Hyun-Wol; Kim, Jae-Won; Jung, Tae-Sung

    2013-01-01

    Of the Salmonella enterica serovars, S. Enteritidis and S. Typhimurium are responsible for most of the Salmonella outbreaks implicated in the consumption of contaminated foods in the Republic of Korea. Because of the widespread occurrence of antimicrobial-resistant Salmonella in foods and food processing environments, bacteriophages have recently surfaced as an alternative biocontrol tool. In this study, we isolated a virulent bacteriophage (wksl3) that could specifically infect S. Enteritidis, S. Typhimurium, and several additional serovars. Transmission electron microscopy revealed that phage wksl3 belongs to the family Siphoviridae. Complete genome sequence analysis and bioinformatic analysis revealed that the DNA of phage wksl3 is composed of 42,766 bp with 64 open reading frames. Since it does not encode any phage lysogeny factors, toxins, pathogen-related genes, or food-borne allergens, phage wksl3 may be considered a virulent phage with no side effects. Analysis of genetic similarities between phage wksl3 and four of its relatives (SS3e, vB_SenS-Ent1, SE2, and SETP3) allowed wksl3 to be categorized as a SETP3-like phage. A single-dose test of oral toxicity with BALB/c mice resulted in no abnormal clinical observations. Moreover, phage application to chicken skin at 8°C resulted in an about 2.5-log reduction in the number of Salmonella bacteria during the test period. The strong, stable lytic activity, the significant reduction of the number of S. Enteritidis bacteria after application to food, and the lack of clinical symptoms of this phage suggest that wksl3 may be a useful agent for the protection of foods against S. Enteritidis and S. Typhimurium contamination. PMID:23335772

  10. Distinct Roles of the Salmonella enterica Serovar Typhimurium CyaY and YggX Proteins in the Biosynthesis and Repair of Iron-Sulfur Clusters

    PubMed Central

    Velayudhan, Jyoti; Karlinsey, Joyce E.; Frawley, Elaine R.; Becker, Lynne A.; Nartea, Margaret

    2014-01-01

    Labile [4Fe-4S]2+ clusters found at the active sites of many dehydratases are susceptible to damage by univalent oxidants that convert the clusters to an inactive [3Fe-4S]1+ form. Bacteria repair damaged clusters in a process that does not require de novo protein synthesis or the Isc and Suf cluster assembly pathways. The current study investigates the participation of the bacterial frataxin ortholog CyaY and the YggX protein, which are proposed to play roles in iron trafficking and iron-sulfur cluster repair. Previous reports found that individual mutations in cyaY or yggX were not associated with phenotypic changes in Escherichia coli and Salmonella enterica serovar Typhimurium, suggesting that CyaY and YggX might have functionally redundant roles. However, we have found that individual mutations in cyaY or yggX confer enhanced susceptibility to hydrogen peroxide in Salmonella enterica serovar Typhimurium. In addition, inactivation of the stm3944 open reading frame, which is located immediately upstream of cyaY and which encodes a putative inner membrane protein, dramatically enhances the hydrogen peroxide sensitivity of a cyaY mutant. Overexpression of STM3944 reduces the elevated intracellular free iron levels observed in an S. Typhimurium fur mutant and also reduces the total cellular iron content under conditions of iron overload, suggesting that the stm3944-encoded protein may mediate iron efflux. Mutations in cyaY and yggX have different effects on the activities of the iron-sulfur cluster-containing aconitase, serine deaminase, and NADH dehydrogenase I enzymes of S. Typhimurium under basal conditions or following recovery from oxidative stress. In addition, cyaY and yggX mutations have additive effects on 6-phosphogluconate dehydratase-dependent growth during nitrosative stress, and a cyaY mutation reduces Salmonella virulence in mice. Collectively, these results indicate that CyaY and YggX play distinct supporting roles in iron-sulfur cluster biosynthesis

  11. Increased Ferroportin-1 Expression and Rapid Splenic Iron Loss Occur with Anemia Caused by Salmonella enterica Serovar Typhimurium Infection in Mice

    PubMed Central

    Nick, Heidi J.; McCoy, Melissa W.; Moreland, Sarah M.; Stepanek, Aaron M.; Benik, Ross; O'Connell, Karyn E.; Pilonieta, Maria C.; Nagy, Toni A.

    2015-01-01

    The Gram-negative intracellular bacterium Salmonella enterica serovar Typhimurium causes persistent systemic inflammatory disease in immunocompetent mice. Following oral inoculation with S. Typhimurium, mice develop a hematopathological syndrome akin to typhoid fever with splenomegaly, microcytic anemia, extramedullary erythropoiesis, and increased hemophagocytic macrophages in the bone marrow, liver, and spleen. Additionally, there is marked loss of iron from the spleen, an unanticipated result, given the iron sequestration reported in anemia of inflammatory disease. To establish why tissue iron does not accumulate, we evaluated multiple measures of pathology for 4 weeks following oral infection in mice. We demonstrate a quantitative decrease in splenic iron following infection despite increased numbers of splenic phagocytes. Infected mice have increased duodenal expression of the iron exporter ferroportin-1, consistent with increased uptake of dietary iron. Liver and splenic macrophages also express high levels of ferroportin-1. These observations indicate that splenic and hepatic macrophages export iron during S. Typhimurium infection, in contrast to macrophage iron sequestration observed in anemia of inflammatory disease. Tissue macrophage export of iron occurs concurrent with high serum concentrations of interferon gamma (IFN-γ) and interleukin 12 (IL-12). In individual mice, high concentrations of both proinflammatory (tumor necrosis factor alpha [TNF-α]) and anti-inflammatory (IL-10) cytokines in serum correlate with increased tissue bacterial loads throughout 4 weeks of infection. These in vivo observations are consistent with previous cell culture studies and suggest that the relocation of iron from tissue macrophages during infection may contribute to anemia and also to host survival of acute S. Typhimurium infection. PMID:25824831

  12. Inactivation of Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 in peanut butter cracker sandwiches by radio-frequency heating.

    PubMed

    Ha, Jae-Won; Kim, Sung-Youn; Ryu, Sang-Ryeol; Kang, Dong-Hyun

    2013-05-01

    A multistate outbreak of Salmonella enterica serovar Typhimurium recently occurred in the USA, which was traced back to various food products made with contaminated peanut butter. This study was conducted to investigate the efficacy of radio-frequency (RF) heating to inactivate S. Typhimurium and Escherichia coli O157:H7 in peanut butter cracker sandwiches using creamy and chunky commercial peanut butter and to determine the effect on quality by measuring color changes and sensory evaluation. Samples were treated for a maximum time of 90 s in a 27.12 MHz RF heating system. Samples were prepared in the form of peanut butter cracker sandwiches and placed in the middle of two parallel-plate electrodes. After 90 s of RF treatment, the log reductions of S. Typhimurium and E. coli O157:H7 were 4.29 and 4.39 log CFU/g, respectively, in creamy peanut butter. RF treatment of chunky peanut butter for 90 s also significantly (P < 0.05) reduced levels of S. Typhimurium and E. coli O157:H7 by 4.55 log CFU/g and 5.32 log CFU/g. Color values and sensory characteristics of the RF treated peanut butter and crackers were not significantly (P > 0.05) different from the control. These results suggest that RF heating can be applied to control pathogens in peanut butter products without affecting quality. PMID:23498191

  13. Increased ferroportin-1 expression and rapid splenic iron loss occur with anemia caused by Salmonella enterica Serovar Typhimurium infection in mice.

    PubMed

    Brown, Diane E; Nick, Heidi J; McCoy, Melissa W; Moreland, Sarah M; Stepanek, Aaron M; Benik, Ross; O'Connell, Karyn E; Pilonieta, Maria C; Nagy, Toni A; Detweiler, Corrella S

    2015-06-01

    The Gram-negative intracellular bacterium Salmonella enterica serovar Typhimurium causes persistent systemic inflammatory disease in immunocompetent mice. Following oral inoculation with S. Typhimurium, mice develop a hematopathological syndrome akin to typhoid fever with splenomegaly, microcytic anemia, extramedullary erythropoiesis, and increased hemophagocytic macrophages in the bone marrow, liver, and spleen. Additionally, there is marked loss of iron from the spleen, an unanticipated result, given the iron sequestration reported in anemia of inflammatory disease. To establish why tissue iron does not accumulate, we evaluated multiple measures of pathology for 4 weeks following oral infection in mice. We demonstrate a quantitative decrease in splenic iron following infection despite increased numbers of splenic phagocytes. Infected mice have increased duodenal expression of the iron exporter ferroportin-1, consistent with increased uptake of dietary iron. Liver and splenic macrophages also express high levels of ferroportin-1. These observations indicate that splenic and hepatic macrophages export iron during S. Typhimurium infection, in contrast to macrophage iron sequestration observed in anemia of inflammatory disease. Tissue macrophage export of iron occurs concurrent with high serum concentrations of interferon gamma (IFN-γ) and interleukin 12 (IL-12). In individual mice, high concentrations of both proinflammatory (tumor necrosis factor alpha [TNF-α]) and anti-inflammatory (IL-10) cytokines in serum correlate with increased tissue bacterial loads throughout 4 weeks of infection. These in vivo observations are consistent with previous cell culture studies and suggest that the relocation of iron from tissue macrophages during infection may contribute to anemia and also to host survival of acute S. Typhimurium infection. PMID:25824831

  14. SadA, a Trimeric Autotransporter from Salmonella enterica Serovar Typhimurium, Can Promote Biofilm Formation and Provides Limited Protection against Infection ▿ †

    PubMed Central

    Raghunathan, Dhaarini; Wells, Timothy J.; Morris, Faye C.; Shaw, Robert K.; Bobat, Saeeda; Peters, Sarah E.; Paterson, Gavin K.; Jensen, Karina Tveen; Leyton, Denisse L.; Blair, Jessica M. A.; Browning, Douglas F.; Pravin, John; Flores-Langarica, Adriana; Hitchcock, Jessica R.; Moraes, Claudia T. P.; Piazza, Roxane M. F.; Maskell, Duncan J.; Webber, Mark A.; May, Robin C.; MacLennan, Calman A.; Piddock, Laura J.; Cunningham, Adam F.; Henderson, Ian R.

    2011-01-01

    Salmonella enterica is a major cause of morbidity worldwide and mortality in children and immunocompromised individuals in sub-Saharan Africa. Outer membrane proteins of Salmonella are of significance because they are at the interface between the pathogen and the host, they can contribute to adherence, colonization, and virulence, and they are frequently targets of antibody-mediated immunity. In this study, the properties of SadA, a purported trimeric autotransporter adhesin of Salmonella enterica serovar Typhimurium, were examined. We demonstrated that SadA is exposed on the Salmonella cell surface in vitro and in vivo during infection of mice. Expression of SadA resulted in cell aggregation, biofilm formation, and increased adhesion to human intestinal Caco-2 epithelial cells. Immunization of mice with folded, full-length, purified SadA elicited an IgG response which provided limited protection against bacterial challenge. When anti-SadA IgG titers were enhanced by administering alum-precipitated protein, a modest additional protection was afforded. Therefore, despite SadA having pleiotropic functions, it is not a dominant, protective antigen for antibody-mediated protection against Salmonella. PMID:21859856

  15. A Lactobacillus acidophilus strain of human gastrointestinal microbiota origin elicits killing of enterovirulent Salmonella enterica Serovar Typhimurium by triggering lethal bacterial membrane damage.

    PubMed

    Coconnier-Polter, Marie-Hélène; Liévin-Le Moal, Vanessa; Servin, Alain L

    2005-10-01

    The human gastrointestinal microbiota produces antagonistic activities against gastrointestinal bacterial pathogens. We undertook a study to investigate the mechanism(s) by which a Lactobacillus acidophilus strain of human microbiota origin antagonizes the gram-negative enteroinvasive pathogen Salmonella enterica serovar Typhimurium. We showed that the cell-free culture supernatant of L. acidophilus strain LB (LB-CFCS) induced the following effects in S. enterica SL1344: (i) a decrease in intracellular ATP that paralleled bacterial death, (ii) the release of lipopolysaccharide, (iii) permeabilization of the bacterial membrane, and (iv) an increase in the sensitivity of Salmonella to the lytic action of sodium dodecyl sulfate. Finally, we showed using two mutant strains of Salmonella, PhoP MS7953s and PmrA JKS1170, that the two-component regulatory systems PhoP-PhoQ and PmrA-PmrB that regulate the mechanisms of resistance to antibacterial agents in Salmonella did not influence the anti-Salmonella effect of LB-CFCS. PMID:16204528

  16. Morphologic and cytokine profile characterization of Salmonella enterica serovar typhimurium infection in calves with bovine leukocyte adhesion deficiency.

    PubMed

    Nunes, J S; Lawhon, S D; Rossetti, C A; Khare, S; Figueiredo, J F; Gull, T; Burghardt, R C; Bäumler, A J; Tsolis, R M; Andrews-Polymenis, H L; Adams, L G

    2010-03-01

    The role of neutrophils in the pathogenesis of Salmonella enterica Typhimurium-induced ruminant and human enteritis and diarrhea has yet to be characterized with in vivo models. To address this question, the in vivo bovine ligated ileal loop model of nontyphoidal salmonellosis was used in calves with the naturally occurring bovine leukocyte adhesion deficiency (BLAD) mutation whose neutrophils are unable to extravasate and infiltrate the extravascular matrix. Data obtained from 4 BLAD Holstein calves homozygous for BLAD (CD18-), 1 to 5 weeks of age, were compared with 4 controls, age-matched Holstein calves negative for BLAD (CD18+). Morphologic studies revealed that infection of CD18- calves with S Typhimurium resulted in no significant tissue infiltration by neutrophils, less tissue damage, reduced luminal fluid accumulation, and increased bacterial invasion, when compared with CD18+ calves. Ultrastructurally, lesions in enterocytes induced by S Typhimurium infection in CD18- calves--including attachment and disruption of the brush border, apical membrane ruffling formation, and cellular degeneration--were similar to the ones reported in the literature for CD18- calves. Study of cytokine gene expression by quantitative real-time polymerase chain reaction revealed that early stages of acute infection (4-8 hours postinfection) were associated with increased interleukin 8 gene expression in the absence of tissue influx of neutrophils in CD18- calves, whereas later stages of infection (12 hours postinfection) were associated with increased expression of growth-related oncogene alpha in the presence of neutrophil influx in CD18+ calves. In contrast, the proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha were poorly correlated with the presence or absence of tissue neutrophils. PMID:20118318

  17. Oral Immunization with ATP-Dependent Protease-Deficient Mutants Protects Mice against Subsequent Oral Challenge with Virulent Salmonella enterica Serovar Typhimurium

    PubMed Central

    Matsui, Hidenori; Suzuki, Masato; Isshiki, Yasunori; Kodama, Chie; Eguchi, Masahiro; Kikuchi, Yuji; Motokawa, Kenji; Takaya, Akiko; Tomoyasu, Toshifumi; Yamamoto, Tomoko

    2003-01-01

    We evaluated the efficacy of mutants with a deletion of the stress response protease gene as candidates for live oral vaccine strains against Salmonella infection through infection studies with mice by using a Salmonella enterica serovar Typhimurium mutant with a disruption of the ClpXP or Lon protease. In vitro, the ClpXP protease regulates flagellum synthesis and the ClpXP-deficient mutant strain exhibits hyperflagellated bacterial cells (T. Tomoyasu et al., J. Bacteriol. 184:645-653, 2002). On the other hand, the Lon protease negatively regulates the efficacy of invading epithelial cells and the expression of invasion genes (A. Takaya et al., J. Bacteriol. 184:224-232, 2002). When 5-week-old BALB/c mice were orally administered 5 × 108 CFU of the ClpXP- or Lon-deficient strain, bacteria were detected with 103 to 104 CFU in the spleen, mesenteric lymph nodes, Peyer's patches, and cecum 1 week after inoculation and the bacteria then decreased gradually in each tissue. Significant increases of lipopolysaccharide-specific immunoglobulin G (IgG) and secretory IgA were detected at week 4 and maintained until at least week 12 after inoculation in serum and bile, respectively. Immunization with the ClpXP- or Lon-deficient strain protected mice against oral challenge with the serovar Typhimurium virulent strain. Both the challenged virulent and immunized avirulent salmonellae were completely cleared from the spleen, mesenteric lymph nodes, Peyer's patches, and even cecum 5 days after the challenge. These data indicate that Salmonella with a disruption of the ATP-dependent protease ClpXP or Lon can be useful in developing a live vaccine strain. PMID:12496146

  18. Proteomic Analysis of Salmonella enterica Serovar Typhimurium Isolated from RAW 264.7 Macrophages: identification of a novel protein that contributes to the replication of serovar Typhimurium inside macrophages

    SciTech Connect

    Shi, Liang; Adkins, Joshua N.; Coleman, James R.; Schepmoes, Athena A.; Dohnalkova, Alice; Mottaz, Heather M.; Norbeck, Angela D.; Purvine, Samuel O.; Manes, Nathan P.; Smallwood, Heather S.; Wang, Haixing H.; Forbes, John; Gros, Philippe; Uzzau, Sergio; Rodland, Karin D.; Heffron, Fred; Smith, Richard D.; Squier, Thomas C.

    2006-09-01

    ABSTRACT: To evade host resistance mechanisms, Salmonella enterica serovar Typhimurium (STM), a facultative intracellular pathogen, must alter its proteome following macrophage infection. To identify new colonization and virulence factors that mediate STM pathogenesis, we have isolated STM cells from RAW 264.7 macrophages at various time-points following infection and used a liquid chromatography-mass spectrometry (LC-MS)-based proteomic approach to detect the changes in STM protein abundances. Because host resistance to STM infection is strongly modulated by the expression of a functional host resistant regulator, i.e., natural resistance associated macrophage protein 1 (Nramp1, also called Slc11a1), we have also examined the effects of Nramp1 activity on the changes of STM protein abundances. A total of 315 STM proteins have been identified from isolated STM cells, which are largely house-keeping proteins whose abundances remain relatively constant during the time-course of infection. However, 39 STM proteins are strongly induced after infection, suggesting their involvement in modulating colonization and infection. Of the 39 induced proteins, 6 proteins are specifically modulated by Nramp1 activity, including STM3117, as well as STM3118-3119 whose time-dependent abundance changes were confirmed using Western blot analysis. Deletion of the gene encoding STM3117 resulted in a dramatic reduction in the ability of STM to colonize wild-type RAW 264.7 macrophages, demonstrating a critical involvement of STM3117 in promoting the replication of STM inside macrophages. The predicted function common for STM3117-3119 is biosynthesis and modification of the peptidoglycan layer of STM cell wall, emphasizing their important roles in the colonization of macrophages by Salmonella.

  19. Pediatric Epidemic of Salmonella enterica Serovar Typhimurium in the Area of L’Aquila, Italy, Four Years after a Catastrophic Earthquake

    PubMed Central

    Nigro, Giovanni; Bottone, Gabriella; Maiorani, Daniela; Trombatore, Fabiana; Falasca, Silvana; Bruno, Gianfranco

    2016-01-01

    Background: A Salmonella enterica epidemic occurred in children of the area of L’Aquila (Central Italy, Abruzzo region) between June 2013 and October 2014, four years after the catastrophic earthquake of 6 April 2009. Methods: Clinical and laboratory data were collected from hospitalized and ambulatory children. Routine investigations for Salmonella infection were carried out on numerous alimentary matrices of animal origin and sampling sources for drinking water of the L’Aquila district, including pickup points of the two main aqueducts. Results: Salmonella infection occurred in 155 children (83 females: 53%), aged 1 to 15 years (mean 2.10). Of these, 44 children (28.4%) were hospitalized because of severe dehydration, electrolyte abnormalities, and fever resistant to oral antipyretic and antibiotic drugs. Three children (1.9%) were reinfected within four months after primary infection by the same Salmonella strain. Four children (2.6%), aged one to two years, were coinfected by rotavirus. A seven-year old child had a concomitant right hip joint arthritis. The isolated strains, as confirmed in about the half of cases or probable/possible in the remaining ones, were identified as S. enterica serovar Typhimurium [4,5:i:-], monophasic variant. Aterno river, bordering the L’Aquila district, was recognized as the main responsible source for the contamination of local crops and vegetables derived from polluted crops. Conclusions: The high rate of hospitalized children underlines the emergence of a highly pathogenic S. enterica strain probably subsequent to the contamination of the spring water sources after geological changes occurred during the catastrophic earthquake. PMID:27164121

  20. The In Vitro Redundant Enzymes PurN and PurT Are Both Essential for Systemic Infection of Mice in Salmonella enterica Serovar Typhimurium.

    PubMed

    Jelsbak, Lotte; Mortensen, Mie I B; Kilstrup, Mogens; Olsen, John E

    2016-07-01

    Metabolic enzymes show a high degree of redundancy, and for that reason they are generally ignored in searches for novel targets for anti-infective substances. The enzymes PurN and PurT are redundant in vitro in Salmonella enterica serovar Typhimurium, in which they perform the third step of purine synthesis. Surprisingly, the results of the current study demonstrated that single-gene deletions of each of the genes encoding these enzymes caused attenuation (competitive infection indexes [CI] of <0.03) in mouse infections. While the ΔpurT mutant multiplied as fast as the wild-type strain in cultured J774A.1 macrophages, net multiplication of the ΔpurN mutant was reduced approximately 50% in 20 h. The attenuation of the ΔpurT mutant was abolished by simultaneous removal of the enzyme PurU, responsible for the formation of formate, indicating that the attenuation was related to formate accumulation or wasteful consumption of formyl tetrahydrofolate by PurU. In the process of further characterization, we disclosed that the glycine cleavage system (GCV) was the most important for formation of C1 units in vivo (CI = 0.03 ± 0.03). In contrast, GlyA was the only important enzyme for the formation of C1 units in vitro The results with the ΔgcvT mutant further revealed that formation of serine by SerA and further conversion of serine into C1 units and glycine by GlyA were not sufficient to ensure C1 formation in S Typhimurium in vivo The results of the present study call for reinvestigations of the concept of metabolic redundancy in S Typhimurium in vivo. PMID:27113361

  1. Extensive amplification of GI-VII-6, a multidrug resistance genomic island of Salmonella enterica serovar Typhimurium, increases resistance to extended-spectrum cephalosporins.

    PubMed

    Lee, Ken-Ichi; Kusumoto, Masahiro; Sekizuka, Tsuyoshi; Kuroda, Makoto; Uchida, Ikuo; Iwata, Taketoshi; Okamoto, Susumu; Yabe, Kimiko; Inaoka, Takashi; Akiba, Masato

    2015-01-01

    GI-VII-6 is a chromosomally integrated multidrug resistance genomic island harbored by a specific clone of Salmonella enterica serovar Typhimurium (S.Typhimurium). It contains a gene encoding CMY-2 β-lactamase (bla CMY-2), and therefore contributes to extended-spectrum cephalosporin resistance. To elucidate the significance of GI-VII-6 on adaptive evolution, spontaneous mutants of S. Typhimurium strain L-3553 were selected on plates containing cefotaxime (CTX). The concentrations of CTX were higher than its minimum inhibition concentration to the parent strain. The mutants appeared on the plates containing 12.5 and 25 mg/L CTX at a frequency of 10(-6) and 10(-8), respectively. No colonies were observed at higher CTX concentrations. The copy number of bla CMY-2 increased up to 85 per genome in the mutants, while the parent strain contains one copy of that in the chromosome. This elevation was accompanied by increased amount of transcription. The bla CMY-2 copy number in the mutants drastically decreased in the absence of antimicrobial selection pressure. Southern hybridization analysis and short-read mapping indicated that the entire 125 kb GI-VII-6 or parts of it were tandemly amplified. GI-VII-6 amplification occurred at its original position, although it also transposed to other locations in the genome in some mutants, including an endogenous plasmid in some of the mutants, leading to the amplification of GI-VII-6 at different loci. Insertion sequences were observed at the junction of the amplified regions in the mutants, suggesting their significant roles in the transposition and amplification. Plasmid copy number in the selected mutants was 1.4 to 4.4 times higher than that of the parent strain. These data suggest that transposition and amplification of the bla CMY-2-containing region, along with the copy number variation of the plasmid, contributed to the extensive amplification of bla CMY-2 and increased resistance to CTX. PMID:25713569

  2. Diversity of Genome Structure in Salmonella enterica Serovar Typhi Populations†

    PubMed Central

    Kothapalli, Sushma; Nair, Satheesh; Alokam, Suneetha; Pang, Tikki; Khakhria, Rasik; Woodward, David; Johnson, Wendy; Stocker, Bruce A. D.; Sanderson, Kenneth E.; Liu, Shu-Lin

    2005-01-01

    The genomes of most strains of Salmonella and Escherichia coli are highly conserved. In contrast, all 136 wild-type strains of Salmonella enterica serovar Typhi analyzed by partial digestion with I-CeuI (an endonuclease which cuts within the rrn operons) and pulsed-field gel electrophoresis and by PCR have rearrangements due to homologous recombination between the rrn operons leading to inversions and translocations. Recombination between rrn operons in culture is known to be equally frequent in S. enterica serovar Typhi and S. enterica serovar Typhimurium; thus, the recombinants in S. enterica serovar Typhi, but not those in S. enterica serovar Typhimurium, are able to survive in nature. However, even in S. enterica serovar Typhi the need for genome balance and the need for gene dosage impose limits on rearrangements. Of 100 strains of genome types 1 to 6, 72 were only 25.5 kb off genome balance (the relative lengths of the replichores during bidirectional replication from oriC to the termination of replication [Ter]), while 28 strains were less balanced (41 kb off balance), indicating that the survival of the best-balanced strains was greater. In addition, the need for appropriate gene dosage apparently selected against rearrangements which moved genes from their accustomed distance from oriC. Although rearrangements involving the seven rrn operons are very common in S. enterica serovar Typhi, other duplicated regions, such as the 25 IS200 elements, are very rarely involved in rearrangements. Large deletions and insertions in the genome are uncommon, except for deletions of Salmonella pathogenicity island 7 (usually 134 kb) from fragment I-CeuI-G and 40-kb insertions, possibly a prophage, in fragment I-CeuI-E. The phage types were determined, and the origins of the phage types appeared to be independent of the origins of the genome types. PMID:15805510

  3. Atmospheric cold plasma inactivation of Escherichia coli, Salmonella enterica serovar Typhimurium and Listeria monocytogenes inoculated on fresh produce.

    PubMed

    Ziuzina, D; Patil, S; Cullen, P J; Keener, K M; Bourke, P

    2014-09-01

    Atmospheric cold plasma (ACP) represents a potential alternative to traditional methods for non-thermal decontamination of foods. In this study, the antimicrobial efficacy of a novel dielectric barrier discharge ACP device against Escherichia coli, Salmonella enterica Typhimurium and Listeria monocytogenes inoculated on cherry tomatoes and strawberries, was examined. Bacteria were spot inoculated on the produce surface, air dried and sealed inside a rigid polypropylene container. Samples were indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (70 kVRMS) air ACP and subsequently stored at room temperature for 24 h. ACP treatment for 10, 60 and 120 s resulted in reduction of Salmonella, E. coli and L. monocytogenes populations on tomato to undetectable levels from initial populations of 3.1, 6.3, and 6.7 log10 CFU/sample, respectively. However, an extended ACP treatment time was necessary to reduce bacterial populations attached on the more complex surface of strawberries. Treatment time for 300 s resulted in reduction of E. coli, Salmonella and L. monocytogenes populations by 3.5, 3.8 and 4.2 log10 CFU/sample, respectively, and also effectively reduced the background microflora of tomatoes. PMID:24929725

  4. Leaching of Cryptosporidium parvum Oocysts, Escherichia coli, and a Salmonella enterica Serovar Typhimurium Bacteriophage through Intact Soil Cores following Surface Application and Injection of Slurry▿

    PubMed Central

    Forslund, Anita; Markussen, Bo; Toenner-Klank, Lise; Bech, Tina B.; Jacobsen, Ole Stig; Dalsgaard, Anders

    2011-01-01

    Increasing amounts of livestock manure are being applied to agricultural soil, but it is unknown to what extent this may be associated with contamination of aquatic recipients and groundwater if microorganisms are transported through the soil under natural weather conditions. The objective of this study was therefore to evaluate how injection and surface application of pig slurry on intact sandy clay loam soil cores influenced the leaching of Salmonella enterica serovar Typhimurium bacteriophage 28B, Escherichia coli, and Cryptosporidium parvum oocysts. All three microbial tracers were detected in the leachate on day 1, and the highest relative concentration was detected on the fourth day (0.1 pore volume). Although the concentration of the phage 28B declined over time, the phage was still found in leachate at day 148. C. parvum oocysts and chloride had an additional rise in the relative concentration at a 0.5 pore volume, corresponding to the exchange of the total pore volume. The leaching of E. coli was delayed compared with that of the added microbial tracers, indicating a stronger attachment to slurry particles, but E. coli could be detected up to 3 months. Significantly enhanced leaching of phage 28B and oocysts by the injection method was seen, whereas leaching of the indigenous E. coli was not affected by the application method. Preferential flow was the primary transport vehicle, and the diameter of the fractures in the intact soil cores facilitated transport of all sizes of microbial tracers under natural weather conditions. PMID:21948848

  5. Kinetic analysis of the antibacterial activity of probiotic lactobacilli towards Salmonella enterica serovar Typhimurium reveals a role for lactic acid and other inhibitory compounds.

    PubMed

    Makras, Lefteris; Triantafyllou, Vagelis; Fayol-Messaoudi, Domitille; Adriany, Tom; Zoumpopoulou, Georgia; Tsakalidou, Effie; Servin, Alain; De Vuyst, Luc

    2006-04-01

    Six Lactobacillus strains including commercial probiotic ones (L. acidophilus IBB 801, L. amylovorus DCE 471, L. casei Shirota, L. johnsonii La1, L. plantarum ACA-DC 287 and L. rhamnosus GG) were investigated, through batch fermentations under controlled conditions, for their capacity to inhibit Salmonella enterica serovar Typhimurium SL1344. All lactobacilli displayed strong antibacterial activity toward this Gram-negative pathogen and significantly inhibited invasion of the pathogen into cultured human enterocyte-like Caco-2/TC7 cells. By studying the production kinetics of antibacterial activity and applying the appropriate acid and pH control samples during a killing assay, we were able to distinguish between the effect of lactic acid and other inhibitory compounds produced. The antibacterial activity of L. acidophilus IBB 801, L. amylovorus DCE 471, L. casei Shirota and L. rhamnosus GG was solely due to the production of lactic acid. The antibacterial activity of L. johnsonii La1 and L. plantarum ACA-DC 287 was due to the production of lactic acid and (an) unknown inhibitory substance(s). The latter was (were) only active in the presence of lactic acid. In addition, the lactic acid produced was responsible for significant inhibitory activity upon invasion of Salmonella into Caco-2/TC7 cells. PMID:16266797

  6. The RcsCDB signaling system and swarming motility in Salmonella enterica serovar typhimurium: dual regulation of flagellar and SPI-2 virulence genes.

    PubMed

    Wang, Qingfeng; Zhao, Yifang; McClelland, Michael; Harshey, Rasika M

    2007-12-01

    The Rcs phosphorelay is a multicomponent signaling system that positively regulates colanic acid synthesis and negatively regulates motility and virulence. We have exploited a spontaneously isolated mutant, IgaA(T191P), that is nearly maximally activated for the Rcs system to identify a vast set of genes that respond to the stimulation, and we report new regulatory properties of this signaling system in Salmonella enterica serovar Typhimurium. Microarray data show that the Rcs system normally functions as a positive regulator of SPI-2 and other genes important for the growth of Salmonella in macrophages, although when highly activated the system completely represses the SPI-1/SPI-2 virulence, flagellar, and fimbrial biogenesis pathways. The auxiliary protein RcsA, which works with RcsB to positively regulate colanic acid and other target genes, not only stimulates but also antagonizes the positive regulation of many genes in the igaA mutant. We show that RcsB represses motility through the RcsB box in the promoter region of the master operon flhDC and that RcsA is not required for this regulation. Curiously, RcsB selectively stimulates expression of the flagellar type 3 secretion genes fliPQR; an RcsAB box located downstream of fliR influences this regulation. We show that excess colanic acid impairs swimming and inhibits swarming motility, consistent with the inverse regulation of the two pathways by the Rcs system. PMID:17905992

  7. Effect of Frequency and Waveform on Inactivation of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in Salsa by Ohmic Heating

    PubMed Central

    Lee, Su-Yeon; Ryu, Sangryeol

    2013-01-01

    The effect of frequency of alternating current during ohmic heating on electrode corrosion, heating rate, inactivation of food-borne pathogens, and quality of salsa was investigated. The impact of waveform on heating rate was also investigated. Salsa was treated with various frequencies (60 Hz to 20 kHz) and waveforms (sine, square, and sawtooth) at a constant electric field strength of 12.5 V/cm. Electrode corrosion did not occur when the frequency exceeded 1 kHz. The heating rate of the sample was dependent on frequency up to 500 Hz, but there was no significant difference (P > 0.05) in the heating rate when the frequency was increased above 1 kHz. The electrical conductivity of the sample increased with a rise in the frequency. At a frequency of 60 Hz, the square wave produced a lower heating rate than that of sine and sawtooth waves. The heating rate between waveforms was not significantly (P > 0.05) different when the frequency was >500 Hz. As the frequency increased, the treatment time required to reduce Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to below the detection limit (1 log CFU/g) decreased without affecting product quality. These results suggest that ohmic heating can be effectively used to pasteurize salsa and that the effect of inactivation is dependent on frequency and electrical conductivity rather than waveform. PMID:23023752

  8. Genes Required for the Fitness of Salmonella enterica Serovar Typhimurium during Infection of Immunodeficient gp91−/− phox Mice

    PubMed Central

    Oshota, Olusegun; Chaudhuri, Roy R.; Mayho, Matthew; Peters, Sarah E.; Clare, Simon; Maskell, Duncan J.; Mastroeni, Pietro

    2016-01-01

    Salmonella enterica causes systemic diseases (typhoid and paratyphoid fever), nontyphoidal septicemia (NTS), and gastroenteritis in humans and other animals worldwide. An important but underrecognized emerging infectious disease problem in sub-Saharan Africa is NTS in children and immunocompromised adults. A current goal is to identify Salmonella mutants that are not pathogenic in the absence of key components of the immune system such as might be found in immunocompromised hosts. Such attenuated strains have the potential to be used as live vaccines. We have used transposon-directed insertion site sequencing (TraDIS) to screen mutants of Salmonella enterica serovar Typhimurium for their ability to infect and grow in the tissues of wild-type and immunodeficient mice. This was to identify bacterial genes that might be deleted for the development of live attenuated vaccines that would be safer to use in situations and/or geographical areas where immunodeficiencies are prevalent. The relative fitness of each of 9,356 transposon mutants, representing mutations in 3,139 different genes, was determined in gp91−/− phox mice. Mutations in certain genes led to reduced fitness in both wild-type and mutant mice. To validate these results, these genes were mutated by allelic replacement, and resultant mutants were retested for fitness in the mice. A defined deletion mutant of cysE was attenuated in C57BL/6 wild-type mice and immunodeficient gp91−/− phox mice and was effective as a live vaccine in wild-type mice. PMID:26787719

  9. Mobilome differences between Salmonella enterica serovars Anatum and Typhimurium isolated from cattle and humans and potential impact on virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica is an important group of pathogens capable of inhabiting a range of niches and hosts with varying degrees of impact, from commensal colonization to invasive infection. Recent outbreaks of multi-drug resistant S. enterica, attributed to consumption of contaminated ...

  10. The Impact of 18 Ancestral and Horizontally-Acquired Regulatory Proteins upon the Transcriptome and sRNA Landscape of Salmonella enterica serovar Typhimurium

    PubMed Central

    Colgan, Aoife M.; Diard, Médéric; Hardt, Wolf-Dietrich; Puente, José L.; Sivasankaran, Sathesh K.; Hokamp, Karsten; Hinton, Jay C. D.

    2016-01-01

    We know a great deal about the genes used by the model pathogen Salmonella enterica serovar Typhimurium to cause disease, but less about global gene regulation. New tools for studying transcripts at the single nucleotide level now offer an unparalleled opportunity to understand the bacterial transcriptome, and expression of the small RNAs (sRNA) and coding genes responsible for the establishment of infection. Here, we define the transcriptomes of 18 mutants lacking virulence-related global regulatory systems that modulate the expression of the SPI1 and SPI2 Type 3 secretion systems of S. Typhimurium strain 4/74. Using infection-relevant growth conditions, we identified a total of 1257 coding genes that are controlled by one or more regulatory system, including a sub-class of genes that reflect a new level of cross-talk between SPI1 and SPI2. We directly compared the roles played by the major transcriptional regulators in the expression of sRNAs, and discovered that the RpoS (σ38) sigma factor modulates the expression of 23% of sRNAs, many more than other regulatory systems. The impact of the RNA chaperone Hfq upon the steady state levels of 280 sRNA transcripts is described, and we found 13 sRNAs that are co-regulated with SPI1 and SPI2 virulence genes. We report the first example of an sRNA, STnc1480, that is subject to silencing by H-NS and subsequent counter-silencing by PhoP and SlyA. The data for these 18 regulatory systems is now available to the bacterial research community in a user-friendly online resource, SalComRegulon. PMID:27564394

  11. No Protective Effects of High-Dosage Dietary Zinc Oxide on Weaned Pigs Infected with Salmonella enterica Serovar Typhimurium DT104

    PubMed Central

    Kreuzer, Susanne; Assmus, Jens; Nöckler, Karsten; Brockmann, Gudrun A.

    2013-01-01

    Twenty-eight-day-old weaned pigs were fed diets with a low (LZn), medium (MZn), or high (MZn) Zn concentration (50 to 80, 150, or 2,500 mg Zn/kg of diet, respectively) provided as zinc oxide (ZnO)(24 pigs per group). They were infected orally with Salmonella enterica serovar Typhimurium DT104 on day 32. Salmonellae were cultivated from feces (up to 42 days postinfection [dpi]) and organs (2 and 42 dpi). Activation of the adaptive systemic and mucosal immune systems was investigated by recording anti-Salmonella IgG levels and levels of B and T lymphocyte subpopulations in blood and gut-associated lymphatic tissue. Growth performance was recorded as well. Salmonellae were shed at higher levels and for longer periods in the HZn group (P < 0.05), with no differences in the tissues. At 2 dpi, the relative percentages of CD4+ T helper cells (P < 0.01) and of CD2+ T and NK cells (P < 0.01) in blood were reduced from the relative cell counts obtained at 0 dpi, irrespective of the Zn group. The lowest percentage of cytotoxic T cells was found 14 dpi in the HZn group relative to the MZn (P < 0.05) and LZn (P < 0.01) groups. Supplementation of the feed with 2,500 mg Zn/kg of diet immediately after weaning could positively affect the immune responses of piglets infected with Salmonella Typhimurium, but for a short period only. After 2 weeks, all positive effects disappeared, and rather negative effects, such as higher shedding of salmonellae, lower T cell frequencies, and worse performance, occurred. Thus, supplementation with ZnO at high levels in the pig industry should be limited to 2 to 3 weeks. PMID:23435881

  12. Development of a novel in-water vaccination protocol for DNA adenine methylase deficient Salmonella enterica serovar Typhimurium vaccine in adult sheep.

    PubMed

    Mohler, V L; Heithoff, D M; Mahan, M J; Hornitzky, M A; Thomson, P C; House, J K

    2012-02-14

    Intensive livestock production is associated with an increased incidence of salmonellosis. The risk of infection and the subsequent public health concern is attributed to increased pathogen exposure and disease susceptibility due to multiple stressors experienced by livestock from farm to feedlot. Traditional parenteral vaccine methods can further stress susceptible populations and cause carcass damage, adverse reactions, and resultant increased production costs. As a potential means to address these issues, in-water delivery of live attenuated vaccines affords a low cost, low-stress method for immunization of livestock populations that is not associated with the adverse handling stressors and injection reactions associated with parenteral administration. We have previously established that in-water administration of a Salmonella enterica serovar Typhimurium dam vaccine conferred significant protection in livestock. While these experimental trials hold significant promise, the ultimate measure of the vaccine will not be established until it has undergone clinical testing in the field wherein environmental and sanitary conditions are variable. Here we show that in-water administration of a S. Typhimurium dam attenuated vaccine was safe, stable, and well-tolerated in adult sheep. The dam vaccine did not alter water consumption or vaccine dosing; remained viable under a wide range of temperatures (21-37°C); did not proliferate within fecal-contaminated trough water; and was associated with minimal fecal shedding and clinical disease as a consequence of vaccination. The capacity of Salmonella dam attenuated vaccines to be delivered in drinking water to protect livestock from virulent Salmonella challenge offers an effective, economical, stressor-free Salmonella prophylaxis for intensive livestock production systems. PMID:22214887

  13. The Impact of 18 Ancestral and Horizontally-Acquired Regulatory Proteins upon the Transcriptome and sRNA Landscape of Salmonella enterica serovar Typhimurium.

    PubMed

    Colgan, Aoife M; Kröger, Carsten; Diard, Médéric; Hardt, Wolf-Dietrich; Puente, José L; Sivasankaran, Sathesh K; Hokamp, Karsten; Hinton, Jay C D

    2016-08-01

    We know a great deal about the genes used by the model pathogen Salmonella enterica serovar Typhimurium to cause disease, but less about global gene regulation. New tools for studying transcripts at the single nucleotide level now offer an unparalleled opportunity to understand the bacterial transcriptome, and expression of the small RNAs (sRNA) and coding genes responsible for the establishment of infection. Here, we define the transcriptomes of 18 mutants lacking virulence-related global regulatory systems that modulate the expression of the SPI1 and SPI2 Type 3 secretion systems of S. Typhimurium strain 4/74. Using infection-relevant growth conditions, we identified a total of 1257 coding genes that are controlled by one or more regulatory system, including a sub-class of genes that reflect a new level of cross-talk between SPI1 and SPI2. We directly compared the roles played by the major transcriptional regulators in the expression of sRNAs, and discovered that the RpoS (σ38) sigma factor modulates the expression of 23% of sRNAs, many more than other regulatory systems. The impact of the RNA chaperone Hfq upon the steady state levels of 280 sRNA transcripts is described, and we found 13 sRNAs that are co-regulated with SPI1 and SPI2 virulence genes. We report the first example of an sRNA, STnc1480, that is subject to silencing by H-NS and subsequent counter-silencing by PhoP and SlyA. The data for these 18 regulatory systems is now available to the bacterial research community in a user-friendly online resource, SalComRegulon. PMID:27564394

  14. No protective effects of high-dosage dietary zinc oxide on weaned pigs infected with Salmonella enterica serovar typhimurium DT104.

    PubMed

    Janczyk, Pawel; Kreuzer, Susanne; Assmus, Jens; Nöckler, Karsten; Brockmann, Gudrun A

    2013-05-01

    Twenty-eight-day-old weaned pigs were fed diets with a low (LZn), medium (MZn), or high (MZn) Zn concentration (50 to 80, 150, or 2,500 mg Zn/kg of diet, respectively) provided as zinc oxide (ZnO)(24 pigs per group). They were infected orally with Salmonella enterica serovar Typhimurium DT104 on day 32. Salmonellae were cultivated from feces (up to 42 days postinfection [dpi]) and organs (2 and 42 dpi). Activation of the adaptive systemic and mucosal immune systems was investigated by recording anti-Salmonella IgG levels and levels of B and T lymphocyte subpopulations in blood and gut-associated lymphatic tissue. Growth performance was recorded as well. Salmonellae were shed at higher levels and for longer periods in the HZn group (P < 0.05), with no differences in the tissues. At 2 dpi, the relative percentages of CD4(+) T helper cells (P < 0.01) and of CD2(+) T and NK cells (P < 0.01) in blood were reduced from the relative cell counts obtained at 0 dpi, irrespective of the Zn group. The lowest percentage of cytotoxic T cells was found 14 dpi in the HZn group relative to the MZn (P < 0.05) and LZn (P < 0.01) groups. Supplementation of the feed with 2,500 mg Zn/kg of diet immediately after weaning could positively affect the immune responses of piglets infected with Salmonella Typhimurium, but for a short period only. After 2 weeks, all positive effects disappeared, and rather negative effects, such as higher shedding of salmonellae, lower T cell frequencies, and worse performance, occurred. Thus, supplementation with ZnO at high levels in the pig industry should be limited to 2 to 3 weeks. PMID:23435881

  15. Two Draft Genome Sequences of a New Serovar of Salmonella enterica, Serovar Lubbock

    PubMed Central

    den Bakker, Henk C.; Nightingale, Kendra K.; Brichta-Harhay, Dayna M.; Edrington, Thomas S.; Loneragan, Guy H.

    2015-01-01

    Salmonella enterica is principally a foodborne pathogen that shows considerable serovar diversity. In this report, we present two draft genome sequences of Salmonella enterica subsp. enterica serovar Lubbock, a novel serovar. PMID:25883279

  16. Two draft genome sequences of a new serovar of Salmonella enterica, serovar Lubbock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is principally a foodborne pathogen that shows considerable serovar diversity. In this report, we present two draft genome sequences of Salmonella enterica subsp. enterica serovar Lubbock, a novel serovar....

  17. 15-Deoxy-Δ12,14-prostaglandin J2 inhibits macrophage colonization by Salmonella enterica serovar Typhimurium.

    PubMed

    Buckner, Michelle M C; Antunes, L Caetano M; Gill, Navkiran; Russell, Shannon L; Shames, Stephanie R; Finlay, B Brett

    2013-01-01

    15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) is an anti-inflammatory downstream product of the cyclooxygenase enzymes. It has been implicated to play a protective role in a variety of inflammatory mediated diseases, including rheumatoid arthritis, neural damage, and myocardial infarctions. Here we show that 15d-PGJ2 also plays a role in Salmonella infection. Salmonella enterica Typhimurium is a Gram-negative facultative intracellular pathogen that is able to survive and replicate inside phagocytic immune cells, allowing for bacterial dissemination to systemic sites. Salmonella species cause a wide range of morbidity and mortality due to gastroenteritis and typhoid fever. Previously we have shown that in mouse models of typhoid fever, Salmonella infection causes a major perturbation in the prostaglandin pathway. Specifically, we saw that 15d-PGJ2 production was significantly increased in both liver and feces. In this work we show that 15d-PGJ2 production is also significantly increased in macrophages infected with Salmonella. Furthermore, we show that the addition of 15d-PGJ2 to Salmonella infected RAW264.7, J774, and bone marrow derived macrophages is sufficient to significantly reduce bacterial colonization. We also show evidence that 15d-PGJ2 is reducing bacterial uptake by macrophages. 15d-PGJ2 reduces the inflammatory response of these infected macrophages, as evidenced by a reduction in the production of cytokines and reactive nitrogen species. The inflammatory response of the macrophage is important for full Salmonella virulence, as it can give the bacteria cues for virulence. The reduction in bacterial colonization is independent of the expression of Salmonella virulence genes SPI1 and SPI2, and is independent of the 15d-PGJ2 ligand PPAR-γ. 15d-PGJ2 also causes an increase in ERK1/2 phosphorylation in infected macrophages. In conclusion, we show here that 15d-PGJ2 mediates the outcome of bacterial infection, a previously unidentified role for this

  18. Inactivation of Bacillus cereus and Salmonella enterica serovar Typhimurium by aqueous ozone (O3): Modeling and Uv-Vis spectroscopic analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ozone (O3) is a natural antimicrobial agent with potential applications in food industry. In this study, inactivation of Bacillus cereus and Salmonella enterica Typhimurium by aqueous ozone was evaluated. Ozone gas was generated using a domestic ozone generator with an output of 200 mg/hr (approx. 0...

  19. Selectively Reduced Intracellular Proliferation of Salmonella enterica Serovar Typhimurium within APCs Limits Antigen Presentation and Development of a Rapid CD8 T Cell Response1

    PubMed Central

    Albaghdadi, Homam; Robinson, Nirmal; Finlay, Brett; Krishnan, Lakshmi; Sad, Subash

    2014-01-01

    Ag presentation to CD8+ T cells commences immediately after infection, which facilitates their rapid expansion and control of pathogen. This paradigm is not followed during infection with virulent Salmonella enterica serovar Typhimurium (ST), an intracellular bacterium that causes mortality in susceptible C57BL/6J mice within 7 days and a chronic infection in resistant mice (129 × 1SvJ). Infection of mice with OVA-expressing ST results in the development of a CD8+ T cell response that is detectable only after the second week of infection despite the early detectable bacterial burden. The mechanism behind the delayed CD8+ T cell activation was evaluated, and it was found that dendritic cells/macrophages or mice infected with ST-OVA failed to present Ag to OVA-specific CD8+ T cells. Lack of early Ag presentation was not rescued when mice or dendritic cells/macrophages were infected with an attenuated aroA mutant of ST or with mutants having defective Salmonella pathogenicity island I/II genes. Although extracellular ST proliferated extensively, the replication of ST was highly muted once inside macrophages. This muted intracellular proliferation of ST resulted in the generation of poor levels of intracellular Ag and peptide-MHC complex on the surface of dendritic cells. Additional experiments revealed that ST did not actively inhibit Ag presentation, rather it inhibited the uptake of another intracellular pathogen, Listeria monocytogenes, thereby causing inhibition of Ag presentation against L. monocytogenes. Taken together, this study reveals a dichotomy in the proliferation of ST and indicates that selectively reduced intra-cellular proliferation of virulent pathogens may be an important mechanism of immune evasion. PMID:19692639

  20. A live oral recombinant Salmonella enterica serovar typhimurium vaccine expressing Clostridium perfringens antigens confers protection against necrotic enteritis in broiler chickens.

    PubMed

    Kulkarni, R R; Parreira, V R; Jiang, Y-F; Prescott, J F

    2010-02-01

    Necrotic enteritis (NE) in broiler chickens is caused by Clostridium perfringens, and there is currently no effective vaccine for NE. We previously showed that in broiler chickens protection against NE can be achieved through intramuscular immunization with alpha toxin (AT) and hypothetical protein (HP), and we subsequently identified B-cell epitopes in HP. In the present study, we identified B-cell epitopes in AT recognized by chickens immune to NE. The gene fragments encoding immunodominant epitopes of AT as well as those of HP were codon optimized for Salmonella and cloned into pYA3493, and the resultant plasmid constructs were introduced into an attenuated Salmonella enterica serovar Typhimurium chi9352 vaccine vehicle. The expression of these Clostridium perfringens proteins, alpha toxoid (ATd) and truncated HP (HPt), was confirmed by immunoblotting. The protection of broiler chickens against experimentally induced NE was assessed at both the moderate and the severe levels of challenge. Birds immunized orally with Salmonella expressing ATd were significantly protected against moderate NE, and there was a nonsignificant trend for protection against severe challenge, whereas HPt-immunized birds were significantly protected against both severities of challenge. Immunized birds developed serum IgY and mucosal IgA and IgY antibody responses against Clostridium and Salmonella antigens. In conclusion, this study identified, for the first time, the B-cell epitopes in AT from an NE isolate recognized by chickens and showed the partial protective ability of codon-optimized ATd and HPt against NE in broiler chickens when they were delivered orally by using a Salmonella vaccine vehicle. PMID:20007363

  1. Synthesis of N-acyl homoserine lactone analogues reveals strong activators of SdiA, the Salmonella enterica serovar Typhimurium LuxR homologue.

    PubMed

    Janssens, Joost C A; Metzger, Kristine; Daniels, Ruth; Ptacek, Dave; Verhoeven, Tine; Habel, Lothar W; Vanderleyden, Jos; De Vos, Dirk E; De Keersmaecker, Sigrid C J

    2007-01-01

    N-Acyl homoserine lactones (AHLs) are molecules that are synthesized and detected by many gram-negative bacteria to monitor the population density, a phenomenon known as quorum sensing. Salmonella enterica serovar Typhimurium is an exceptional species since it does not synthesize its own AHLs, while it does encode a LuxR homologue, SdiA, which enables this bacterium to detect AHLs that are produced by other species. To obtain more information about the specificity of the ligand binding by SdiA, we synthesized and screened a limited library of AHL analogues. We identified two classes of analogues that are strong activators of SdiA: the N-(3-oxo-acyl)-homocysteine thiolactones (3O-AHTLs) and the N-(3-oxo-acyl)-trans-2-aminocyclohexanols. To our knowledge, this is the first report of compounds (the 3O-AHTLs) that are able to activate a LuxR homologue at concentrations that are lower than the concentrations of the most active AHLs. SdiA responds with greatest sensitivity to AHTLs that have a keto modification at the third carbon atom and an acyl chain that is seven or eight carbon atoms long. The N-(3-oxo-acyl)-trans-2-aminocyclohexanols were found to be less sensitive to deactivation by lactonase and alkaline pH than the 3O-AHTLs and the AHLs are. We also examined the activity of our library with LuxR of Vibrio fischeri and identified three new inhibitors of LuxR. Finally, we performed preliminary binding experiments which suggested that SdiA binds its activators reversibly. These results increase our understanding of the specificity of the SdiA-ligand interaction, which could have uses in the development of anti-quorum-sensing-based antimicrobials. PMID:17085703

  2. Immunogenicity of a live recombinant Salmonella enterica serovar typhimurium vaccine expressing pspA in neonates and infant mice born from naive and immunized mothers.

    PubMed

    Shi, Huoying; Wang, Shifeng; Roland, Kenneth L; Gunn, Bronwyn M; Curtiss, Roy

    2010-03-01

    We are developing a Salmonella vectored vaccine to prevent infant pneumonia and other diseases caused by Streptococcus pneumoniae. One prerequisite for achieving this goal is to construct and evaluate new recombinant attenuated Salmonella vaccine (RASV) strains suitable for use in neonates and infants. Salmonella enterica serovar Typhimurium strain chi9558(pYA4088) specifies delivery of the pneumococcal protective antigen PspA and can protect adult mice from challenge with S. pneumoniae. This strain is completely safe for oral delivery to day-old and infant mice. Here we assess the colonizing ability, immunogenicity, and protective efficacy of chi9558(pYA4088) in neonatal mice. Colonization was assessed in mice 0, 2, 4, or 7 days of age after oral inoculation. In the presence of maternal antibodies, the colonization of lymphoid tissues was delayed, but the immune responses were enhanced in mice born to immunized mothers. Both oral and intranasal routes were used to assess immunogenicity. All orally or intranasally immunized neonatal and infant mice born to either immunized or naïve mothers developed PspA-specific mucosal and systemic immune responses. Mice born to immunized mothers produced higher titers of PspA-specific antibodies in the blood and mucosa and greater numbers of PspA-specific interleukin-4 (IL-4)-secreting cells than mice born to naïve mothers. More importantly, mice born to immune mothers showed a significant increase in protection against S. pneumoniae challenge. These results suggest that strain chi9558(pYA4088) can circumvent some of the limitations of the immature immune system in neonatal and infant mice, generating enhanced protective immune responses in the presence of maternal antibodies. PMID:20053873

  3. Construction and Immunological Evaluation of Dual Cell Surface Display of HIV-1 Gag and Salmonella enterica Serovar Typhimurium FliC in Lactobacillus acidophilus for Vaccine Delivery

    PubMed Central

    Kajikawa, Akinobu; Zhang, Lin; Long, Julie; Nordone, Shila; Stoeker, Laura; LaVoy, Alora; Bumgardner, Sara; Klaenhammer, Todd

    2012-01-01

    Oral vaccines that elicit a mucosal immune response may be effective against human immunodeficiency virus type 1 (HIV-1) because its transmission occurs mainly at the mucosa. The aim of this study was to construct recombinant Lactobacillus for oral delivery of oral vaccines against HIV-1 and to evaluate their immunogenicity. A recombinant Lactobacillus acidophilus strain expressing the HIV-1 Gag on the bacterial cell surface was established by fusion with the signal peptide and anchor motif of a mucus binding protein (Mub) from L. acidophilus with or without coexpression of Salmonella enterica serovar Typhimurium flagellin (FliC) fused to a different Mub signal peptide and anchor. Using HEK293 cells engineered to express Toll-like receptor 5 (TLR5), the biological activity of FliC on the bacterial cell surfaces was determined. The surface-exposed flagellin retained its TLR5-stimulating activity, suggesting that the recombinant strain with Gag and FliC dual display might provide a different immunopotency than the strain expressing only Gag. The immunological properties of the recombinant strains were assessed by coculture with human myeloid dendritic cells (DCs). The heterologous antigens on the cell surface affected maturation and cytokine responses of DCs. Acquired immune responses were also investigated by intragastric immunization of mice. The enzyme-linked immunosorbent spot assay showed induction of gamma interferon-producing cells at local mucosa after immunization of mice with the Gag-producing strain. Meanwhile, the immunization with L. acidophilus displaying both Gag and FliC resulted in an increase of Gag-specific IgA-secreting cells. These results suggested that the Gag-displaying L. acidophilus elicited specific immune responses and the coexistence of FliC conferred an adjuvant effect on local IgA production. PMID:22761297

  4. Pronounced susceptibility to infection by Salmonella enterica serovar Typhimurium in mice chronically exposed to lead correlates with a shift to Th2-type immune responses

    SciTech Connect

    Fernandez-Cabezudo, Maria J.; Ali, Sumaya A.E.; Ullah, Azim; Hasan, Mohammed Y.; Kosanovic, Melita; Fahim, Mohamed A.; Adem, Abdu; Al-Ramadi, Basel K. . E-mail: ramadi.b@uaeu.ac.ae

    2007-02-01

    Persistent exposure to inorganic lead (Pb) is known to adversely affect the immune system. In the present study, we assessed the effect of chronic Pb exposure on susceptibility to infection by the facultative intracellular pathogen Salmonella enterica serovar Typhimurium. Mice were exposed to 10 mM Pb-acetate in drinking water for {approx} 16 weeks, resulting in a significant level of Pb in the blood (106.2 {+-} 8.9 {mu}g/dl). Pb exposure rendered mice susceptible to Salmonella infection, manifested by increased bacterial burden in target organs and heightened mortality. Flow cytometric analysis of the splenic cellular composition in normal and Pb-exposed mice revealed no gross alteration in the ratios of B and T lymphocytes or myeloid cells. Similarly, the capacity of B and T cells to upregulate the expression of activation antigens in response to mitogenic or inflammatory stimuli was not hindered by Pb exposure. Analysis of the ability of ex vivo-cultured splenocytes to secrete cytokines demonstrated a marked reduction in IFN-{gamma} and IL-12p40 production associated with Pb exposure. In contrast, secretion of IL-4 by splenocytes of Pb-treated mice was 3- to 3.6-fold higher than in normal mice. The increased capacity to produce IL-4 correlated with a shift in the in vivo anti-Salmonella antibody response from the protective IgG2a isotype to the Th2-induced IgG1 isotype. We conclude that chronic exposure to high levels of Pb results in a state of immunodeficiency which is not due to an overt cytotoxic or immunosuppressive mechanism, but rather is largely caused by a shift in immune responsiveness to Th2-type reactions.

  5. Intravaginal Immunization of Mice with Recombinant Salmonella enterica Serovar Typhimurium Expressing Human Papillomavirus Type 16 Antigens as a Potential Route of Vaccination against Cervical Cancer▿

    PubMed Central

    Echchannaoui, Hakim; Bianchi, Matteo; Baud, David; Bobst, Martine; Stehle, Jean-Christophe; Nardelli-Haefliger, Denise

    2008-01-01

    Cervical cancer, the second leading cause of cancer deaths in women, is the consequence of high-risk human papillomavirus (HPV) infections. Toward the development of therapeutic vaccines that can induce both innate and adaptive mucosal immune responses, we analyzed intravaginal (ivag) vaccine delivery of live attenuated Salmonella enterica serovar Typhimurium expressing HPV16L1 as a model antigen. Innate immune responses were examined in cervicovaginal tissues by determining gene expression patterns by microarray analysis using nylon membranes imprinted with cDNA fragments coding for inflammation-associated genes. At 24 h, a wide range of genes, including those for chemokines and Th1- and Th2-type cytokine and chemokine receptors were up-regulated in mice ivag immunized with Salmonella compared to control mice. However, the majority of transcripts returned to their steady-state levels 1 week after immunization, suggesting a transient inflammatory response. Indeed, cervicovaginal histology of immunized mice showed a massive, but transient, infiltration of macrophages and neutrophils, while T cells were still increased after 7 days. Ivag immunization also induced humoral and antitumor immune responses, i.e., serum and vaginal anti-HPV16VLP antibody titers similar to those induced by oral immunization, and significant protection in tumor protection experiments using HPV16-expressing C3 tumor cells. These results show that ivag immunization with live attenuated Salmonella expressing HPV16 antigens modulates the local mucosal gene expression pattern into a transient proinflammatory profile, elicits strong systemic and mucosal immunity against HPV16, and confers protection against HPV16 tumor cells subcutaneously implanted in mice. Examination of the efficacy with which ivag HPV16E7E6 Salmonella induces regression of tumors located in cervicovaginal tissue is warranted. PMID:18332214

  6. FimY of Salmonella enterica serovar Typhimurium functions as a DNA-binding protein and binds the fimZ promoter.

    PubMed

    Wang, Ke-Chuan; Hsu, Yuan-Hsun; Huang, Yi-Ning; Lin, Jiunn-Horng; Yeh, Kuang-Sheng

    2014-01-01

    Salmonella enterica serovar Typhimurium produces type 1 fimbriae with binding specificity to mannose residues. Elements involved in fimbrial structural biosynthesis, transport, and regulation are encoded by the fim gene cluster. FimZ, FimY, FimW, STM0551, and an arginine transfer RNA (fimU) were previously demonstrated to regulate fimbrial expression. The amino acid sequences of the C-terminal portion of FimY revealed similarity with those of LuxR-like proteins. Electrophoretic mobility shift assays indicated that FimY possessed DNA-binding capacity and bound a 605-bp DNA fragment spanning the intergenic region between fimY and fimZ, while a FimY protein harboring a double mutation in the C-terminal helix-turn-helix region containing a glycine (G) to aspartate (D) substitution at residue 189 and isoleucine (I) to lysine (K) substitution at residue 195 lost its ability to bind this DNA fragment. A lux box sequence (5'-TCTGTTATTACATAACAAATACT-3') within the fimZ promoter was required for binding. None of the DNA fragments derived from the promoters for fimA, fimY, or fimW was shifted by FimY. Pull-down assays showed that there were physical protein/protein interactions between FimY and FimZ. We propose that in the regulatory circuit of type 1 fimbriae, FimY functions as a DNA-binding protein to activate fimZ, and a FimY-FimZ protein complex may form to regulate other fim genes. Confirming these proposals requires further study. PMID:24462182

  7. Genomic Analysis of Salmonella enterica Serovar Typhimurium Characterizes Strain Diversity for Recent U.S. Salmonellosis Cases and Identifies Mutations Linked to Loss of Fitness under Nitrosative and Oxidative Stress

    PubMed Central

    Hayden, Hillary S.; Matamouros, Susana; Hager, Kyle R.; Brittnacher, Mitchell J.; Rohmer, Laurence; Radey, Matthew C.; Weiss, Eli J.; Kim, Katie B.; Jacobs, Michael A.; Sims-Day, Elizabeth H.; Yue, Min; Zaidi, Mussaret B.; Schifferli, Dieter M.; Manning, Shannon D.; Walson, Judd L.

    2016-01-01

    ABSTRACT Salmonella enterica serovar Typhimurium is one of the most common S. enterica serovars associated with U.S. foodborne outbreaks. S. Typhimurium bacteria isolated from humans exhibit wide-ranging virulence phenotypes in inbred mice, leading to speculation that some strains are more virulent in nature. However, it is unclear whether increased virulence in humans is related to organism characteristics or initial treatment failure due to antibiotic resistance. Strain diversity and genetic factors contributing to differential human pathogenicity remain poorly understood. We reconstructed phylogeny, resolved genetic population structure, determined gene content and nucleotide variants, and conducted targeted phenotyping assays for S. Typhimurium strains collected between 1946 and 2012 from humans and animals in the United States and abroad. Strains from recent U.S. salmonellosis cases were associated with five S. Typhimurium lineages distributed within three phylogenetic clades, which are not restricted by geography, year of acquisition, or host. Notably, two U.S. strains and four Mexican strains are more closely related to strains associated with human immunodeficiency virus (HIV)-infected individuals in sub-Saharan Africa than to other North American strains. Phenotyping studies linked variants specific to these strains in hmpA and katE to loss of fitness under nitrosative and oxidative stress, respectively. These results suggest that U.S. salmonellosis is caused by diverse S. Typhimurium strains circulating worldwide. One lineage has mutations in genes affecting fitness related to innate immune system strategies for fighting pathogens and may be adapting to immunocompromised humans by a reduction in virulence capability, possibly due to a lack of selection for its maintenance as a result of the worldwide HIV epidemic. PMID:26956590

  8. A multi-pronged search for a common structural motif in the secretion signal of Salmonella enterica serovar Typhimurium type III effector proteins

    PubMed Central

    Buchko, Garry W.; Niemann, George; Baker, Erin S.; Belov, Mikhail E.; Smith, Richard D.; Heffron, Fred; Adkins, Joshua N.; McDermott, Jason E.

    2012-01-01

    Many pathogenic Gram-negative bacteria use a type III secretion system (T3SS) to deliver effector proteins into the host cell where they reprogram host defenses and facilitate pathogenesis. The first 20–30 N-terminal residues usually contain the ‘secretion signal’ that targets effector proteins for translocation, however, a consensus sequence motif has never been discerned. Recent machine-learning approaches, such as support vector machine (SVM)-based Identification and Evaluation of Virulence Effectors (SIEVE), have improved the ability to identify effector proteins from genomics sequence information. While these methods all suggest that the T3SS secretion signal has a characteristic amino acid composition bias, it is still unclear if the amino acid pattern is important and if there are any unifying structural properties that direct recognition. To address these issues a peptide corresponding to the secretion signal for Salmonella enterica serovar Typhimurium effector SseJ was synthesized (residues 1–30, SseJ) along with scrambled peptides of the same amino acid composition that produced high (SseJ-H) and low (SseJ-L) SIEVE scores. The secretion properties of these three peptides were tested using a secretion signal–CyaA fusion assay and their structural properties probed using circular dichroism, nuclear magnetic resonance, and ion mobility spectrometry–mass spectrometry. The secretion predictions from SIEVE matched signal–CyaA fusion experimental results with J774 macrophages suggesting that the SseJ secretion signal has some sequence order dependence. The structural studies showed that the SseJ, SseJ-H, and SseJ-L peptides were intrinsically disordered in aqueous solution with a small predisposition to adopt nascent helical structure only in the presence of structure stabilizing agents such as 1,1,1,3,3,3-hexafluoroisopropanol. Intrinsic disorder may be a universal feature of effector secretion signals as similar conclusions were reached following

  9. A multi-pronged search for a common structural motif in the secretion signal of Salmonella enterica serovar Typhimurium type III effector proteins

    SciTech Connect

    Buchko, Garry W.; Niemann, George; Baker, Erin Shammel; Belov, Mikhail E.; Smith, Richard D.; Heffron, Fred; Adkins, Joshua N.; McDermott, Jason E.

    2010-11-08

    Many pathogenic Gram-negative bacteria use a type III secretion system (T3SS) to deliver effector proteins into the host cell where they reprogram host defenses and facilitate pathogenesis. While it has been determined that the first 20 - 30 N-terminal residues usually contain the ‘secretion signal’ that targets effector proteins for translocation, the molecular basis for recognition of this signal is not understood. Recent machine-learning approaches, such as SVM-based Identification and Evaluation of Virulence Effectors (SIEVE), have improved the ability to identify effector proteins from genomics sequence information. While these methods all suggest that the T3SS secretion signal has a characteristic amino acid composition bias, it is still unclear if the amino acid pattern is important and if there are any unifying structural properties that direct recognition. To address these issues a peptide corresponding to the secretion signal for Salmonella enterica serovar Typhimurium effector SseJ was synthesized (residues 1-30, SseJ) along with scrambled peptides of the same amino acid composition that produced high (SseJ-H) and low (SseJ-L) SIEVE scores. The secretion properties of these three peptides were tested using a secretion signal-CyaA fusion assay and their structures systematically probed using circular dichroism, nuclear magnetic resonance, and ion mobility spectrometry-mass spectrometry. The signal-CyaA fusion assay showed that the native and SseJ-H fusion constructs were secreted into J774 macrophage at similar levels via the SPI-2 secretion pathway while secretion of the SseJ-L fusion construct was substantially retarded, suggesting that the SseJ secretion signal was sequence order dependent. The structural studies showed that the SseJ, SseJ-H, and SseJ-L peptides were intrinsically disordered in aqueous solution with only a small predisposition to adopt nascent helical structure in the presence of the powerful structure stabilizing agent, 1

  10. New decontamination method based on caprylic acid in combination with citric acid or vanillin for eliminating Cronobacter sakazakii and Salmonella enterica serovar Typhimurium in reconstituted infant formula.

    PubMed

    Choi, M J; Kim, S A; Lee, N Y; Rhee, M S

    2013-09-16

    The antimicrobial effects of natural compounds (caprylic acid, CA; citric acid, CTA; and vanillin, VNL) on the inactivation of Cronobacter sakazakii and Salmonella enterica serovar Typhimurium were examined in reconstituted infant formula. The samples were treated with: 1) CA, CTA, or VNL alone (0, 10, 20, 30, 40, 60, and 80 mM); 2) a combination of CA (10 and 20 mM) and CTA (15 and 30 mM); and 3) a combination of CA (10 and 20 mM) and VNL (15 and 30 mM), at mild feeding temperatures (40 °C and 45 °C), and the bacterial populations were assayed periodically (0, 5, 10, and 30 min). For both bacteria, the combined treatments had marked synergistic antimicrobial effects compared with the sum of the effects of each individual treatment. For example, there was no noticeable reduction (P > 0.05) in the population of C. sakazakii following an individual treatment with 20 mM CA or 30 mM CTA for 5 min at 40 °C, whereas the population was reduced to undetectable levels (reduction > 7.3 log CFU/ml) following treatment with a combination of CA and CTA (20 CA+30 CTA for 5 min at 40 °C). As the temperature increased, the bactericidal effect was stronger at all time points with a synergistic effect. In a validation assay using a low level inoculum (approximately 10³ CFU/ml) of desiccation-stressed bacteria in certain conditions, the combined treatments (e.g., CA 10 mM+CTA 30 mM for 5 min at 45 °C for C. sakazakii, and CA 10mM+VNL 15 mM for 10 min at 45 °C for S. Typhimurium) completely destroyed the bacteria with no recovery of cell viability. Disintegration of the membrane and changes in the cell structure or morphology, such as plasmolysis and membrane disruption, were detected by flow cytometry and electron microscopy, respectively. These methods use antimicrobials that could be applied as food additives in infant formula, which may help to eliminate bacteria. PMID:24042002

  11. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorate is a bactericide that has potential as a pre-slaughter feed additive to improve food safety of meat products. The aims of the present study were to examine the effects of chlorate (5mM), molybdate (1 mM), and shikimate (0.34 mM) on the growth and chlorate-resistance of Salmonella enterica ...

  12. The agricultural antibiotic carbadox induces generalized transducing phage in multidrug-resistant Salmonella enterica serovar Typhimurium DT104

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-typhoidal Salmonella, a leading cause of U.S. foodborne disease and food-related deaths, often asymptomatically colonizes food-producing animals. In fact, >50% of U.S. swine production facilities test positive for Salmonella. The multidrug-resistant (MDR) Salmonella Typhimurium DT104 NCTC13348 c...

  13. Levels of Expression and Immunogenicity of Attenuated Salmonella enterica Serovar Typhimurium Strains Expressing Escherichia coli Mutant Heat-Labile Enterotoxin

    PubMed Central

    Covone, M. Giuseppina; Brocchi, Marcelo; Palla, Emanuela; da Silveira, W. Dias; Rappuoli, Rino; Galeotti, Cesira L.

    1998-01-01

    The effects of heterologous gene dosage as well as Salmonella typhimurium strain variability on immune response toward both the heterologous antigen, the nontoxic mutant of the Escherichia coli heat-labile enterotoxin LTK63, and the carrier Salmonella strain have been analyzed. Effects of a single integration into the host DNA and different-copy-number episomal vectors were compared in S. typhimurium Δcya Δcrp Δasd strains of two different serotypes, UK-1 and SR-11. Expression of the enterotoxin in the different Salmonella isolates in vitro was found to vary considerably and, for the episomal vectors, to correlate with the plasmid copy number. LTK63-specific serum immunoglobulin G (IgG) and mucosal immunoglobulin A (IgA) antibodies were highest in mice immunized with the high-level-expression strain. High anti-LTK63 IgG and IgA titers were found to correspond to higher anti-Salmonella immunity, suggesting that LTK63 exerts an adjuvant effect on response to the carrier. Statistically significant differences in anti-LTK63 immune response were observed between groups of mice immunized with the attenuated Δcya Δcrp UK-1 and SR-11 derivatives producing the antigen at the same rate. These data indicate that the same attenuation in S. typhimurium strains of different genetic backgrounds can influence significantly the immune response toward the heterologous antigen. Moreover, delivery of the LTK63 enterotoxin to the immune system by attenuated S. typhimurium strains is effective only when synthesis of the antigen is very high during the initial phase of invasion, while persistence of the S. typhimurium strain in deep tissues has only marginal influence. PMID:9423862

  14. Improvement of bacterial clearance and relief of clinical signs of Salmonella enterica serovar Typhimurium infection in pigs through upregulation of Th 1-specific responses by administration of a combination of two silicate minerals, biotite and bentonite

    PubMed Central

    LEE, Jin-A; JUNG, Bock-Gie; KIM, Tae-Hoon; KIM, Yun-Mi; KOH, Hong-Bum; LEE, Bong-Joo

    2015-01-01

    Biotite and bentonite are phyllosilicate minerals that were originally used in industrial applications. Several beneficial activities of them have recently been reported, especially regulation of the immune system and antimicrobial effects. Therefore, we investigated the immune-enhancing and bacterial clearance effects of a biotite and bentonite mixture (BBM) on experimental infection of Salmonella enterica serovar Typhimurium (S. Typhimurium) to determine whether the BBM could be used as an alternative antibiotic. We administered 1% or 2% BBM as a feed supplement. We then evaluated the bacterial clearance effects of the BBM against S. Typhimurium. We also evaluated the immune-enhancing effect of the BBM through several immunological experiments that included examination of the lysozyme activity, CD4+/CD8+ T lymphocyte ratio and the T-helper type 1 (Th 1) cytokine profile. The clinical signs of S. Typhimurium and the number of viable bacteria in feces and tissues were significantly decreased in both BBM groups, especially in the 2% BBM group. The BBM also markedly enhanced the lysozyme activity, CD4+/CD8+ T lymphocyte ratio and expression levels of IFN-γ and IL-12 in S. Typhimurium-challenged pigs. Therefore, the BBM could be a good candidate as an alternative antibiotic that improves Th 1-specific immune responses and the bacterial clearance effect. PMID:25947887

  15. Dam methylation regulates the expression of SPI-5-encoded sopB gene in Salmonella enterica serovar Typhimurium.

    PubMed

    Giacomodonato, Mónica N; Llana, Mariángeles Noto; Castañeda, María del Rosario Aya; Buzzola, Fernanda; García, Mauro D; Calderón, Marina Gallo; Sarnacki, Sebastián H; Cerquetti, María C

    2014-08-01

    DNA adenine methylation is an essential factor in Salmonella virulence. Here, we investigate the involvement of DNA adenine methylase (Dam) in the expression and translocation of a SPI-5-encoded effector of S. Typhimurium. SopB expression and secretion were determined using SopB-FLAG-tagged wild type and dam strains of S. Typhimurium. Western blot and quantitative reverse transcriptase PCR analysis showed that the dam mutant expresses lower levels of SopB protein and sopB mRNA than the wild type strain under SPI-1 and SPI-2 inducing conditions in vitro. SopB secretion was also considerably impaired in the absence of dam. In agreement with in vitro experiments, SopB synthesis in dam mutants recovered from infected epithelial cells and from murine mesenteric lymph nodes was reduced by 40% respect to the wild type strain (p < 0.05). SopB translocation was neither detected in the cytosol of epithelial cells nor in the cytosol of cells isolated from mesenteric lymph nodes infected with the dam mutant. Taken together, our results demonstrate that, in S. Typhimurium, Dam methylation modulates the expression and translocation of SPI-5-encoded SopB effector. PMID:24947562

  16. The small regulatory RNA molecule MicA is involved in Salmonella enterica serovar Typhimurium biofilm formation

    PubMed Central

    2010-01-01

    Background LuxS is the synthase enzyme of the quorum sensing signal AI-2. In Salmonella Typhimurium, it was previously shown that a luxS deletion mutant is impaired in biofilm formation. However, this phenotype could not be complemented by extracellular addition of quorum sensing signal molecules. Results Analysis of additional S. Typhimurium luxS mutants indicated that the LuxS enzyme itself is not a prerequisite for a wild type mature biofilm. However, in close proximity of the luxS coding sequence, a small RNA molecule, MicA, is encoded on the opposite DNA strand. Interference with the MicA expression level showed that a balanced MicA level is essential for mature Salmonella biofilm formation. Several MicA targets known to date have previously been reported to be implicated in biofilm formation in Salmonella or in other bacterial species. Additionally, we showed by RT-qPCR analysis that MicA levels are indeed altered in some luxS mutants, corresponding to their biofilm formation phenotype. Conclusions We show that the S. Typhimurium biofilm formation phenotype of a luxS mutant in which the complete coding region is deleted, is dependent on the sRNA molecule MicA, encoded in the luxS adjacent genomic region, rather than on LuxS itself. Future studies are required to fully elucidate the role of MicA in Salmonella biofilm formation. PMID:21044338

  17. An attenuated Salmonella enterica serovar Typhimurium strain reduces disease severity, fecal shedding, and gastrointestinal colonization in swine due to virulent S. Typhimurium challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Salmonella serovars frequently colonize swine without causing overt disease. Pathogen interventions are needed to limit Salmonella colonization in swine. Vaccination with an attenuated Salmonella strain may reduce pathogen carriage in swine and enhance food safety. Methods: Swine study ...

  18. Acquisition of Mn(II) in Addition to Fe(II) Is Required for Full Virulence of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Boyer, E.; Bergevin, I.; Malo, D.; Gros, P.; Cellier, M. F. M.

    2002-01-01

    The roles of the genes feoB (ABC ferrous iron transporter), mntH (proton-dependent manganese transporter), and sitABCD (putative ABC iron and/or manganese transporter) in Salmonella pathogenicity were investigated by using mutant strains deficient in one, two, or three transporters. Our results indicated that sitABCD encodes an important transporter of Mn(II) and Fe(II) which is required for full virulence in susceptible animals (Nramp1−/−) and for replication inside Nramp1−/− macrophages in vitro. The mntH sitABCD double mutant (mutant MS) showed minimal Mn(II) uptake and increased sensitivity to H2O2 and to the divalent metal chelator 2,2′-dipyridyl (DP) and was defective for replication in macrophages. In vivo MS appeared to be as virulent as the sitABCD mutant in Nramp1−/− animals. The ferrous iron transporter Feo was required for full virulence in 129/Sv Nramp1−/− mice, and infection with multiple mutants lacking FeoB was not fatal. The sitABCD feoB mutant (mutant SF) and the mntH sitABCD feoB mutant (mutant MSF) showed minimal Fe(II) uptake and were slightly impaired for replication in susceptible macrophages. MSF showed reduced growth in minimal medium deficient in divalent cations. The role of the mntH gene, which is homologous to mammalian Nramp genes, was also investigated after overexpression in the double mutant MS. MntH preferred Mn(II) over Fe(II) and could suppress MS sensitivity to H2O2 and to DP, and it also improved the intracellular survival in Nramp1−/− macrophages. This study indicates that acquisition of Mn(II), in addition to Fe(II), is required for intracellular survival and replication of Salmonella enterica serovar Typhimurium in macrophages in vitro and for virulence in vivo. PMID:12379679

  19. NsrR: a key regulator circumventing Salmonella enterica serovar Typhimurium oxidative and nitrosative stress in vitro and in IFN-gamma-stimulated J774.2 macrophages.

    PubMed

    Gilberthorpe, Nicola J; Lee, Margaret E; Stevanin, Tania M; Read, Robert C; Poole, Robert K

    2007-06-01

    Over the past decade, the flavohaemoglobin Hmp has emerged as the most significant nitric oxide (NO)-detoxifying protein in many diverse micro-organisms, particularly pathogenic bacteria. Its expression in enterobacteria is dramatically increased on exposure to NO and other agents of nitrosative stress as a result of transcriptional regulation of hmp gene expression, mediated by (at least) four regulators. One such regulator, NsrR, has recently been shown to be responsible for repression of hmp transcription in the absence of NO in Escherichia coli and Salmonella, but the roles of other members of this regulon in Salmonella, particularly in surviving nitrosative stresses in vitro and in vivo, have not been elucidated. This paper demonstrates that an nsrR mutant of Salmonella enterica Serovar Typhimurium expresses high levels of Hmp both aerobically and anaerobically, exceeding those that can be elicited in vitro by supplementing media with S-nitrosoglutathione (GSNO). Elevated transcription of ytfE, ygbA, hcp and hcp is also observed, but no evidence was obtained for tehAB upregulation. The hyper-resistance to GSNO of an nsrR mutant is attributable solely to Hmp, since an nsrR hmp double mutant has a wild-type phenotype. However, overexpression of NsrR-regulated genes other than hmp confers some resistance of respiratory oxygen consumption to NO. The ability to enhance, by mutating NsrR, Hmp levels without recourse to exposure to nitrosative stress was used to test the hypothesis that control of Hmp levels is required to avoid oxidative stress, Hmp being a potent generator of superoxide. Within IFN-gamma-stimulated J774.2 macrophages, in which high levels of nitrite accumulated (indicative of NO production) an hmp mutant was severely compromised in survival. Surprisingly, under these conditions, an nsrR mutant (as well as an nsrR hmp double mutant) was also disadvantaged relative to the wild-type bacteria, attributable to the combined oxidative effect of the

  20. Salmonella enterica serovar Typhimurium immunotherapy for B-cell lymphoma induces broad anti-tumour immunity with therapeutic effect

    PubMed Central

    Grille, Sofía; Moreno, María; Bascuas, Thais; Marqués, Juan M; Muñoz, Natalia; Lens, Daniela; Chabalgoity, Jose A

    2014-01-01

    Despite the efficacy of current immune-chemotherapy for treatment of B-cell non-Hodgkin lymphoma, a substantial proportion of patients relapse, highlighting the need for new therapeutic modalities. The use of live microorganisms to develop anti-tumoural therapies has evolved since Coley's toxin and is now receiving renewed attention. Salmonella Typhimurium has been shown to be highly effective as an anti-tumour agent in many solid cancer models, but it has not been used in haemato-oncology. Here, we report that intra-tumoural administration of LVR01 (attenuated S. Typhimurium strain with safety profile) elicits local and systemic anti-tumour immunity, resulting in extended survival in a lymphoma model. LVR01 induces intra-tumoural recruitment of neutrophils and activated CD8+ T cells, as well as increasing the natural killer cell activation status. Furthermore, a systemic specific anti-tumour response with a clear T helper type 1 profile was observed. This approach is an alternative therapeutic strategy for lymphoma patients that could be easily moved into clinical trials. PMID:24834964

  1. Evidence of metabolic switching and implications for food safety from the phenome(s) of Salmonella enterica serovar Typhimurium DT104 cultured at selected points across the pork production food chain.

    PubMed

    Martins, Marta; McCusker, Matthew P; McCabe, Evonne M; O'Leary, Denis; Duffy, Geraldine; Fanning, Séamus

    2013-09-01

    Salmonella enterica serovar Typhimurium DT104 is a recognized food-borne pathogen that displays a multidrug-resistant phenotype and that is associated with systemic infections. At one extreme of the food chain, this bacterium can infect humans, limiting the treatment options available and thereby contributing to increased morbidity and mortality. Although the antibiotic resistance profile is well defined, little is known about other phenotypes that may be expressed by this pathogen at key points across the pork production food chain. In this study, 172 Salmonella enterica serovar Typhimurium DT104/DT104b isolated from an extensive "farm-to-fork" surveillance study, focusing on the pork food chain, were characterized in detail. Isolates were cultured from environmental, processing, retail, and clinical sources, and the study focused on phenotypes that may have contributed to persistence/survival in these different niches. Molecular subtypes, along with antibiotic resistance profiles, tolerance to biocides, motility, and biofilm formation, were determined. As a basis for human infection, acid survival and the ability to utilize a range of energy sources and to adhere to and/or invade Caco-2 cells were also studied. Comparative alterations to biocide tolerance were observed in isolates from retail. l-Tartaric acid and d-mannose-1-phosphate induced the formation of biofilms in a preselected subset of strains, independent of their origin. All clinical isolates were motile and demonstrated an enhanced ability to survive in acidic conditions. Our data report on a diverse phenotype, expressed by S. Typhimurium isolates cultured from the pork production food chain. Extending our understanding of the means by which this pathogen adapts to environmental niches along the "farm-to-fork" continuum will facilitate the protection of vulnerable consumers through targeted improvements in food safety measures. PMID:23770904

  2. Evidence of Metabolic Switching and Implications for Food Safety from the Phenome(s) of Salmonella enterica Serovar Typhimurium DT104 Cultured at Selected Points across the Pork Production Food Chain

    PubMed Central

    Martins, Marta; McCusker, Matthew P.; McCabe, Evonne M.; O'Leary, Denis; Duffy, Geraldine

    2013-01-01

    Salmonella enterica serovar Typhimurium DT104 is a recognized food-borne pathogen that displays a multidrug-resistant phenotype and that is associated with systemic infections. At one extreme of the food chain, this bacterium can infect humans, limiting the treatment options available and thereby contributing to increased morbidity and mortality. Although the antibiotic resistance profile is well defined, little is known about other phenotypes that may be expressed by this pathogen at key points across the pork production food chain. In this study, 172 Salmonella enterica serovar Typhimurium DT104/DT104b isolated from an extensive “farm-to-fork” surveillance study, focusing on the pork food chain, were characterized in detail. Isolates were cultured from environmental, processing, retail, and clinical sources, and the study focused on phenotypes that may have contributed to persistence/survival in these different niches. Molecular subtypes, along with antibiotic resistance profiles, tolerance to biocides, motility, and biofilm formation, were determined. As a basis for human infection, acid survival and the ability to utilize a range of energy sources and to adhere to and/or invade Caco-2 cells were also studied. Comparative alterations to biocide tolerance were observed in isolates from retail. l-Tartaric acid and d-mannose-1-phosphate induced the formation of biofilms in a preselected subset of strains, independent of their origin. All clinical isolates were motile and demonstrated an enhanced ability to survive in acidic conditions. Our data report on a diverse phenotype, expressed by S. Typhimurium isolates cultured from the pork production food chain. Extending our understanding of the means by which this pathogen adapts to environmental niches along the “farm-to-fork” continuum will facilitate the protection of vulnerable consumers through targeted improvements in food safety measures. PMID:23770904

  3. Genes Required for the Fitness of Salmonella enterica Serovar Typhimurium during Infection of Immunodeficient gp91-/- phox Mice.

    PubMed

    Grant, Andrew J; Oshota, Olusegun; Chaudhuri, Roy R; Mayho, Matthew; Peters, Sarah E; Clare, Simon; Maskell, Duncan J; Mastroeni, Pietro

    2016-04-01

    Salmonella entericacauses systemic diseases (typhoid and paratyphoid fever), nontyphoidal septicemia (NTS), and gastroenteritis in humans and other animals worldwide. An important but underrecognized emerging infectious disease problem in sub-Saharan Africa is NTS in children and immunocompromised adults. A current goal is to identifySalmonellamutants that are not pathogenic in the absence of key components of the immune system such as might be found in immunocompromised hosts. Such attenuated strains have the potential to be used as live vaccines. We have used transposon-directed insertion site sequencing (TraDIS) to screen mutants ofSalmonella entericaserovar Typhimurium for their ability to infect and grow in the tissues of wild-type and immunodeficient mice. This was to identify bacterial genes that might be deleted for the development of live attenuated vaccines that would be safer to use in situations and/or geographical areas where immunodeficiencies are prevalent. The relative fitness of each of 9,356 transposon mutants, representing mutations in 3,139 different genes, was determined ingp91(-/-)phoxmice. Mutations in certain genes led to reduced fitness in both wild-type and mutant mice. To validate these results, these genes were mutated by allelic replacement, and resultant mutants were retested for fitness in the mice. A defined deletion mutant ofcysEwas attenuated in C57BL/6 wild-type mice and immunodeficientgp91(-/-)phoxmice and was effective as a live vaccine in wild-type mice. PMID:26787719

  4. Effects of cattle feeding regimen and soil management type on the fate of Escherichia coli O157:H7 and salmonella enterica serovar typhimurium in manure, manure-amended soil, and lettuce.

    PubMed

    Franz, Eelco; van Diepeningen, Anne D; de Vos, Oscar J; van Bruggen, Ariena H C

    2005-10-01

    Survival of the green fluorescent protein-transformed human pathogens Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium was studied in a laboratory-simulated lettuce production chain. Dairy cows were fed three different roughage types: high-digestible grass silage plus maize silage (6:4), low-digestible grass silage, and straw. Each was adjusted with supplemental concentrates to high and low crude protein levels. The pathogens were added to manure, which was subsequently mixed (after 56 and 28 days for E. coli O157:H7 and Salmonella serovar Typhimurium, respectively) with two pairs of organically and conventionally managed loamy and sandy soil. After another 14 days, iceberg lettuce seedlings were planted and then checked for pathogens after 21 days of growth. Survival data were fitted to a logistic decline function (exponential for E. coli O157:H7 in soil). Roughage type significantly influenced the rate of decline of E. coli O157:H7 in manure, with the fastest decline in manure from the pure straw diet and the slowest in manure from the diet of grass silage plus maize silage. Roughage type showed no effect on the rate of decline of Salmonella serovar Typhimurium, although decline was significantly faster in the manure derived from straw than in the manure from the diet of grass silage plus maize silage. The pH and fiber content of the manure were significant explanatory factors and were positively correlated with the rate of decline. With E. coli O157:H7 there was a trend of faster decline in organic than in conventional soils. No pathogens were detected in the edible lettuce parts. The results indicate that cattle diet and soil management are important factors with respect to the survival of human pathogens in the environment. PMID:16204535

  5. Transcriptional response of selected genes of Salmonella enterica serovar Typhimurium biofilm cells during inactivation by superheated steam.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun; Yoon, Hyunjin

    2015-01-01

    Superheated steam (SHS), produced by the addition of heat to saturated steam (SS) at the same pressure, has great advantages over conventional heat sterilization due to its high temperature and accelerated drying rate. We previously demonstrated that treatment with SHS at 200°C for 10 sec inactivated Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilm cells on the surface of stainless steel to below the detection limit. However, bacteria withstanding heat stress become more resistant to other stress conditions, and may be more virulent when consumed by a host. Herein, we studied the transcriptional regulation of genes important for stress resistance and virulence in Salmonella biofilms after SHS treatments. Genes encoding heat shock proteins and general stress resistance proteins showed transcriptional surges after 1 sec of SHS treatment at 200°C, with parallel induction of stress-related regulator genes including rpoE, rpoS, and rpoH. Interestingly, Salmonella biofilm cells exposed to SHS showed decreased transcription of flagella and Salmonella pathogenicity island-1 (SPI-1) genes required for motility and invasion of host cells, respectively, whereas increased transcription of SPI-2 genes, important for bacterial survival and replication inside host cells, was detected. When the transcriptional response was compared between cells treated with SHS (200°C) and SS (100°C), SHS caused immediate changes in gene expression by shorter treatments. Understanding the status of Salmonella virulence and stress resistance induced by SHS treatments is important for wider application of SHS in controlling Salmonella biofilm formation during food production. PMID:25440555

  6. Cold plasma inactivation of internalised bacteria and biofilms for Salmonella enterica serovar Typhimurium, Listeria monocytogenes and Escherichia coli.

    PubMed

    Ziuzina, Dana; Han, Lu; Cullen, Patrick J; Bourke, Paula

    2015-10-01

    Microbial biofilms and bacteria internalised in produce tissue may reduce the effectiveness of decontamination methods. In this study, the inactivation efficacy of in-package atmospheric cold plasma (ACP) afterglow was investigated against Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli in the forms of planktonic cultures, biofilms formed on lettuce and associated bacteria internalised in lettuce tissue. Prepared lettuce broth (3%) was inoculated with bacteria resulting in a final concentration of ~7.0 log10 CFU/ml. For biofilm formation and internalisation, lettuce pieces (5 × 5 cm) were dip-inoculated in bacterial suspension of ~7.0 log10 CFU/ml for 2 h and further incubated for 0, 24 and 48 h at either 4 °C or room temperature (~22 °C) in combination with light/dark photoperiod or at 4 °C under dark conditions. Inoculated samples were sealed inside a rigid polypropylene container and indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (80 kVRMS) air ACP with subsequent storage for 24 h at 4 °C. ACP treatment for 30s reduced planktonic populations of Salmonella, L. monocytogenes and E. coli suspended in lettuce broth to undetectable levels. Depending on storage conditions, bacterial type and age of biofilm, 300 s of treatment resulted in reduction of biofilm populations on lettuce by a maximum of 5 log10 CFU/sample. Scanning electron and confocal laser microscopy pointed to the incidence of bacterial internalisation and biofilm formation, which influenced the inactivation efficacy of ACP. Measured intracellular reactive oxygen species (ROS) revealed that the presence of organic matter in the bacterial suspension might present a protective effect against the action of ROS on bacterial cells. This study demonstrated that high voltage in-package ACP could be a potential technology to overcome bacterial challenges associated with food produce. However, the existence of biofilms and internalised bacteria should be

  7. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791).

    PubMed

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J; Payne, Justin; Allard, Marc W; Hoffmann, Maria

    2016-01-01

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791). PMID:26988049

  8. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791)

    PubMed Central

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J.; Payne, Justin; Allard, Marc W.

    2016-01-01

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791). PMID:26988049

  9. Mutational analysis of the Escherichia coli PhoQ sensor kinase: differences with the Salmonella enterica serovar Typhimurium PhoQ protein and in the mechanism of Mg2+ and Ca2+ sensing.

    PubMed

    Regelmann, Adam G; Lesley, Joseph A; Mott, Christina; Stokes, Lissette; Waldburger, Carey D

    2002-10-01

    The PhoP-PhoQ two-component system plays a role in Mg2+ homeostasis and/or the virulence properties of a number of bacterial species. A Salmonella enterica serovar Typhimurium PhoQ sensor kinase mutant, in which the threonine at residue 48 in the periplasmic sensor domain is changed to an isoleucine, was shown previously to result in elevated expression of PhoP-activated genes and to affect mouse virulence, epithelial cell invasion, and sensitivity to macrophage killing. We characterized a complete set of proteins having amino acid substitutions at position 48 in the closely related Escherichia coli PhoQ protein. Numerous mutant proteins having amino acid substitutions with side chains of various sizes and characters displayed signaling phenotypes similar to that of the wild-type protein, indicating that interactions mediated by the wild-type threonine side chain are not required for normal protein function. Changes to amino acids with aromatic side chains had little impact on signaling in response to extracellular Mg2+ but resulted in reduced sensitivity to extracellular Ca2+, suggesting that the mechanisms of signal transduction in response to these two divalent cations are different. Surprisingly, the Ile48 protein displayed a defective phenotype rather than the hyperactive phenotype seen with the S. enterica serovar Typhimurium protein. We also describe a mutant PhoQ protein lacking the extracellular sensor domain with a defect in the ability to activate PhoP. The defect does not appear to be due to reduced autokinase activity but rather appears to be due to an effect on the stability of the aspartyl-phosphate bond of phospho-PhoP. PMID:12218035

  10. Simultaneous Near-Infrared Radiant Heating and UV Radiation for Inactivating Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in Powdered Red Pepper (Capsicum annuum L.)

    PubMed Central

    Ha, Jae-Won

    2013-01-01

    This study was conducted to investigate the efficacy of the simultaneous application of near-infrared (NIR) heating and UV irradiation for reducing populations of food-borne pathogens, including Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 in red pepper powder and to clarify the mechanisms of the lethal effect of the NIR-UV combined treatment. Also, the effect of the combination treatment on quality was determined by measuring changes in color and pungency constituents. Simultaneous NIR-UV combined treatment for 5 min achieved 3.34- and 2.78-log CFU reductions in S. Typhimurium and E. coli O157:H7, respectively, which involved 1.86- and 1.31-log CFU reductions, respectively, which were attributed to the synergistic effect. Through qualitative and quantitative analyses, damage to the cell envelope was identified as the main factor contributing to the synergistic lethal effect of NIR-UV combined treatment. Color values and capsaicin and dihydrocapsaicin content of NIR-UV simultaneously treated red pepper powder were not significantly (P > 0.05) different from those of untreated samples. These results suggest that simultaneous application of NIR and UV treatment can be effectively used to control food-borne pathogens in powdered red pepper without affecting quality. PMID:23956394

  11. Emergence of a multidrug-resistant (ASSuTTm) strain of Salmonella enterica serovar Typhimurium DT120 in England in 2011 and the use of multiple-locus variable-number tandem-repeat analysis in supporting outbreak investigations.

    PubMed

    Paranthaman, Karthikeyan; Haroon, Sophie; Latif, Samia; Vinnyey, Natalie; de Souza, Valerie; Welfare, William; Tahir, Mamoona; Cooke, Edward; Stone, Kirsten; Lane, Chris; Peters, Tansy; Puleston, Richard

    2013-10-01

    In summer 2011, two outbreaks of a unique, multidrug-resistant strain of Salmonella enterica serovar Typhimurium phage type 120 (DT120) occurred mainly in the Midlands, England. The first outbreak occurred among guests attending a wedding in July 2011 ('Wedding outbreak'), followed by a more geographically dispersed outbreak in August and September 2011 ('Midlands outbreak'). Fifty-one cases were confirmed. Detailed epidemiological and environmental health investigations suggested that pork was the most likely source of both outbreaks. All human samples and one pork sample showed the specific multiple-locus variable-number tandem-repeat analysis (MLVA) profile 3-11-12-NA-0211, with at most two loci variations. Trace-back investigations suggested a link to a butcher's shop and a pig farm in the East Midlands. The investigations highlight the utility of molecular analysis (MLVA) in supporting epidemiological investigations of outbreaks caused by S. Typhimurium DT120. Safe handling and cooking of pork by food business operators and consumers are key interventions to prevent future outbreaks. PMID:23869962

  12. A comprehensive study of the contribution of Salmonella enterica serovar Typhimurium SPI2 effectors to bacterial colonization, survival, and replication in typhoid fever, macrophage, and epithelial cell infection models.

    PubMed

    Buckner, Michelle M C; Croxen, Matthew A; Arena, Ellen T; Finlay, B Brett

    2011-01-01

    Salmonella enterica serovars are Gram-negative bacterial pathogens responsible for human diseases including gastroenteritis and typhoid fever. After ingestion, Salmonella cross the intestinal epithelial barrier, where they are phagocytosed by macrophages and dendritic cells, which then enables their spread to systemic sites during cases of typhoid fever. Salmonella use two type 3 secretion systems encoded by Salmonella pathogenicity islands (SPI) 1 and 2 to inject virulence proteins into host cells to modify cellular functions. SPI1 is involved in host cell invasion and inflammation, whereas SPI2 is required for intracellular survival and replication within phagocytes, and systemic spread. In this study the contribution of nearly all known SPI2 effectors was examined in an in vivo model of murine typhoid fever and cell culture models of macrophage and epithelial cell infection. Unmarked, in-frame deletions of SPI2 effectors were engineered in S. enterica serovar Typhimurium and the ability of the 16 different mutants to colonize and replicate was examined. In the typhoid model, we found that ΔspvB and ΔspiC mutants were attenuated for colonization of intestinal and systemic sites, while the ΔsseF mutant was attenuated in systemic organs. In epithelial cells, all mutants replicated to the same extent as the wild-type. In macrophages, ΔspiC, ΔsteC, ΔspvB, ΔssseK1/K2/K3, ΔsifA, and ΔsifB strains replicated poorly in comparison to wild-type Salmonella. This study provides a thorough screen of the majority of the known SPI2 effectors evaluated under the same conditions in various models of infection, providing a foundation for comparative examination of the roles and interactions of these effectors. PMID:21540636

  13. The distribution of Salmonella enterica serovars and subtypes in surface water from five agricultural regions across Canada.

    PubMed

    Jokinen, C C; Koot, J; Cole, L; Desruisseau, A; Edge, T A; Khan, I U H; Koning, W; Lapen, D R; Pintar, K D M; Reid-Smith, R; Thomas, J L; Topp, E; Wang, L Y; Wilkes, G; Ziebell, K; van Bochove, E; Gannon, V P J

    2015-06-01

    Serovar prevalence of the zoonotic pathogen, Salmonella enterica, was compared among 1624 surface water samples collected previously from five different Canadian agricultural watersheds over multiple years. Phagetyping, pulsed field gel electrophoresis (PFGE), and antimicrobial resistance subtyping assays were performed on serovars Enteritidis, Typhimurium, and Heidelberg. Serovars and subtypes from surface water were compared with those from animal feces, human sewage, and serovars reported to cause salmonellosis in Canadians. Sixty-five different serovars were identified in surface water; only 32% of these were isolated from multiple watersheds. Eleven of the 13 serovars most commonly reported to cause salmonellosis in Canadians were identified in surface water; isolates of these serovars constituted >40% of the total isolates. Common phagetypes and PFGE subtypes of serovars associated with illness in humans such as S. Enteritidis and S. Typhimurium were also isolated from surface water and animal feces. Antimicrobial resistance was generally low, but was highest among S. Typhimurium. Monitoring of these rivers helps to identify vulnerable areas of a watershed and, despite a relatively low prevalence of S. enterica overall, serovars observed in surface water are an indication of the levels of specific S. enterica serovars present in humans and animals. PMID:25799976

  14. Modulation of Biofilm-Formation in Salmonella enterica Serovar Typhimurium by the Periplasmic DsbA/DsbB Oxidoreductase System Requires the GGDEF-EAL Domain Protein STM3615

    PubMed Central

    Römling, Ute; Rhen, Mikael

    2014-01-01

    In Salmonella enterica serovar Typhimurium (S. Typhimurium), biofilm-formation is controlled by the cytoplasmic intracellular small-molecular second messenger cyclic 3′, 5′-di- guanosine monophosphate (c-di-GMP) through the activities of GGDEF and EAL domain proteins. Here we describe that deleting either dsbA or dsbB, respectively encoding a periplasmic protein disulfide oxidase and a cytoplasmic membrane disulfide oxidoreductase, resulted in increased biofilm-formation on solid medium. This increased biofilm-formation, defined as a red, dry and rough (rdar) colony morphotype, paralleled with enhanced expression of the biofilm master regulator CsgD and the biofilm-associated fimbrial subunit CsgA. Deleting csgD in either dsb mutant abrogated the enhanced biofilm-formation. Likewise, overexpression of the c-di-GMP phosphodiesterase YhjH, or mutationally inactivating the CsgD activator EAL-domain protein YdiV, reduced biofilm-formation in either of the dsb mutants. Intriguingly, deleting the GGDEF-EAL domain protein gene STM3615 (yhjK), previously not connected to rdar morphotype development, also abrogated the escalated rdar morphotype formation in dsb mutant backgrounds. Enhanced biofilm-formation in dsb mutants was furthermore annulled by exposure to the protein disulfide catalyst copper chloride. When analyzed for the effect of exogenous reducing stress on biofilm-formation, both dsb mutants initially showed an escalated rdar morphotype development that later dissolved to reveal a smooth mucoid colony morphotype. From these results we conclude that biofilm-development in S. Typhimurium is affected by periplasmic protein disulphide bond status through CsgD, and discuss the involvement of selected GGDEF/EAL domain protein(s) as signaling mediators. PMID:25153529

  15. The Vi Capsular Polysaccharide Enables Salmonella enterica Serovar Typhi to Evade Microbe-Guided Neutrophil Chemotaxis

    PubMed Central

    Wangdi, Tamding; Lee, Cheng-Yuk; Spees, Alanna M.; Yu, Chenzhou; Kingsbury, Dawn D.; Winter, Sebastian E.; Hastey, Christine J.; Wilson, R. Paul

    2014-01-01

    Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium) is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a) and C5a receptor (C5aR). Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi) capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis. PMID:25101794

  16. Effect of drinking-water administration of experimental chlorate ion preparations on Salmonella enterica serovar Typhimurium colonization in weaned and finished pigs.

    PubMed

    Anderson, R C; Hume, M E; Genovese, K J; Callaway, T R; Jung, Y S; Edrington, T S; Poole, T L; Harvey, R B; Bischoff, K M; Nisbet, D J

    2004-04-01

    Foodborne disease caused by Salmonella is of public health and economic significance. In order to assess the practical effectiveness of a new intervention strategy, experimental chlorate preparations (ECP) were administered via the drinking water to weaned and finished pigs that had been orally challenged the previous day with 10(9)-10(10) colony-forming units of Salmonella serovar Typhimurium. After 24 or 36 h ad libitum access to 0X, 1X or 2X ECP treatment (where X is the concentration estimated to deliver a minimal daily effective dose), the pigs were euthanized and gut contents and lymph tissue collected at necropsy were cultured for the challenge Salmonella. Drinking water administration of ECP effectively reduced (p < 0.05) caecal Salmonella concentrations and, with the weaned pigs, tended (p < or = 0.10) to reduce rectal Salmonella concentrations. No negative effects of ECP treatment on water intake and animal wellbeing were observed and only marginal effects on gut fermentation characteristics occurred. The bactericidal effect of administering ECP in drinking water was relatively rapid, with reductions in caecal Salmonella concentrations occurring within 24 h. These results suggest that ECP administered to pigs just days before slaughter may reduce gut concentrations of Salmonella; however, the impacts of such reductions on slaughter hygiene have yet to be determined. PMID:15074764

  17. Influence of moisture content on inactivation of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in powdered red and black pepper spices by radio-frequency heating.

    PubMed

    Jeong, Seul-Gi; Kang, Dong-Hyun

    2014-04-17

    The influence of moisture content during radio-frequency (RF) heating on heating rate, dielectric properties, and inactivation of foodborne pathogens was investigated. The effect of RF heating on the quality of powdered red and black pepper spices with different moisture ranges was also investigated. Red pepper (12.6%, 15.2%, 19.1%, and 23.3% dry basis, db) and black pepper (10.1%, 17.2%, 23.7%, and 30.5% db) inoculated with Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium were treated in a RF heating system with 27.12 MHz. The heating rate of the sample was dependent on moisture content up to 19.1% (db) of red pepper and 17.2% (db) of black pepper, but there was a significant decrease in the heating rate when the moisture content was increased beyond these levels. The dielectric properties of both samples increased with a rise in moisture content. As the moisture content increased, treatment time required to reduce E. coli O157:H7 and S. Typhimurium by more than 7 log CFU/g (below the detection limit, 1 log CFU/g) decreased and then increased again without affecting product quality when the moisture content exceeded a level corresponding to the peak heating rate. RF treatment significantly (P<0.05) reduced moisture content of both spices. These results suggest that RF heating can be effectively used to not only control pathogens but also reduce moisture levels in spices and that the effect of inactivation is dependent on moisture content. PMID:24555992

  18. Salmonella enterica: Survival, Colonization, and Virulence Differences among Serovars

    PubMed Central

    Andino, A.; Hanning, I.

    2015-01-01

    Data indicate that prevalence of specific serovars of Salmonella enterica in human foodborne illness is not correlated with their prevalence in feed. Given that feed is a suboptimal environment for S. enterica, it appears that survival in poultry feed may be an independent factor unrelated to virulence of specific serovars of Salmonella. Additionally, S. enterica serovars appear to have different host specificity and the ability to cause disease in those hosts is also serovar dependent. These differences among the serovars may be related to gene presence or absence and expression levels of those genes. With a better understanding of serovar specificity, mitigation methods can be implemented to control Salmonella at preharvest and postharvest levels. PMID:25664339

  19. Molecular differentiation between Salmonella enterica subsp enterica serovar Pullorum and Salmonella enterica subsp enterica serovar Gallinarum

    PubMed Central

    Ribeiro, Simone Alves Mendes; de Paiva, Jaqueline Boldrin; Zotesso, Fábio; Lemos, Manoel Victor Franco; Berchieri Jánior, Ângelo

    2009-01-01

    S. Pullorum (SP) and S. Gallinarum (SG) are very similar. They are the agents of pullorum disease and fowl typhoid, respectively, and the two diseases are responsible for economic losses in poultry production. Although SP and SG are difficult to be differentiated in routine laboratory procedures, the ability to metabolize ornithine is a biochemical test that may be used to achieve this aim. While SP is able to decarboxylate this amino acid, SG is not. However, the isolation of strains showing atypical biochemical behavior has made this differentiation difficult. One of the genes associated with the metabolization of the amino acid ornithine is called speC, and is found in both serovars. The analysis of 21 SP and 15 SG strains by means of PCR did not enable the differentiation of the two serovars, because fragments produced were identical. However, after enzymatic treatment with restriction enzyme Eco RI, the band pattern of each serovar showed to be different, even in samples of atypical biochemical behavior. This fact enabled the standardization of the technique for a quick and safe differentiation of serovars Pullorum and Gallinarum. PMID:24031341

  20. Infection with Salmonella enterica Serovar Typhimurium Leads to Increased Proportions of F4/80+ Red Pulp Macrophages and Decreased Proportions of B and T Lymphocytes in the Spleen

    PubMed Central

    Rosche, Kristin L.; Aljasham, Alanoud T.; Kipfer, James N.; Piatkowski, Bryan T.; Konjufca, Vjollca

    2015-01-01

    Infection of mice with Salmonella enterica serovar Typhimurium (Salmonella) causes systemic inflammatory disease and enlargement of the spleen (splenomegaly). Splenomegaly has been attributed to a general increase in the numbers of phagocytes, lymphocytes, as well as to the expansion of immature CD71+Ter119+ reticulocytes. The spleen is important for recycling senescent red blood cells (RBCs) and for the capture and eradication of blood-borne pathogens. Conservation of splenic tissue architecture, comprised of the white pulp (WP), marginal zone (MZ), and red pulp (RP) is essential for initiation of adaptive immune responses to captured pathogens. Using flow cytometry and four color immunofluorescence microscopy (IFM), we show that Salmonella-induced splenomegaly is characterized by drastic alterations of the splenic tissue architecture and cell population proportions, as well as in situ cell distributions. A major cause of splenomegaly appears to be the significant increase in immature RBC precursors and F4/80+ macrophages that are important for recycling of heme-associated iron. In contrast, the proportions of B220+, CD4+ and CD8+ lymphocytes, as well as MZ MOMA+ macrophages decrease significantly as infection progresses. Spleen tissue sections show visible tears and significantly altered tissue architecture with F4/80+ macrophages and RBCs expanding beyond the RP and taking over most of the spleen tissue. Additionally, F4/80+ macrophages actively phagocytose not only RBCs, but also lymphocytes, indicating that they may contribute to declining lymphocyte proportions during Salmonella infection. Understanding how these alterations of spleen microarchitecture impact the generation of adaptive immune responses to Salmonella has implications for understanding Salmonella pathogenesis and for the design of more effective Salmonella-based vaccines. PMID:26068006

  1. Sublethal Exposure to Commercial Formulations of the Herbicides Dicamba, 2,4-Dichlorophenoxyacetic Acid, and Glyphosate Cause Changes in Antibiotic Susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium

    PubMed Central

    Kurenbach, Brigitta; Marjoshi, Delphine; Amábile-Cuevas, Carlos F.; Ferguson, Gayle C.; Godsoe, William; Gibson, Paddy

    2015-01-01

    ABSTRACT Biocides, such as herbicides, are routinely tested for toxicity but not for sublethal effects on microbes. Many biocides are known to induce an adaptive multiple-antibiotic resistance phenotype. This can be due to either an increase in the expression of efflux pumps, a reduced synthesis of outer membrane porins, or both. Exposures of Escherichia coli and Salmonella enterica serovar Typhimurium to commercial formulations of three herbicides—dicamba (Kamba), 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate (Roundup)—were found to induce a changed response to antibiotics. Killing curves in the presence and absence of sublethal herbicide concentrations showed that the directions and the magnitudes of responses varied by herbicide, antibiotic, and species. When induced, MICs of antibiotics of five different classes changed up to 6-fold. In some cases the MIC increased, and in others it decreased. Herbicide concentrations needed to invoke the maximal response were above current food maximum residue levels but within application levels for all herbicides. Compounds that could cause induction had additive effects in combination. The role of soxS, an inducer of the AcrAB efflux pump, was tested in β-galactosidase assays with soxS-lacZ fusion strains of E. coli. Dicamba was a moderate inducer of the sox regulon. Growth assays with Phe-Arg β-naphtylamide (PAβN), an efflux pump inhibitor, confirmed a significant role of efflux in the increased tolerance of E. coli to chloramphenicol in the presence of dicamba and to kanamycin in the presence of glyphosate. Pathways of exposure with relevance to the health of humans, domestic animals, and critical insects are discussed. PMID:25805724

  2. Effect of Electropermeabilization by Ohmic Heating for Inactivation of Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium, and Listeria monocytogenes in Buffered Peptone Water and Apple Juice

    PubMed Central

    Park, Il-Kyu

    2013-01-01

    The effect of electric field-induced ohmic heating for inactivation of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in buffered peptone water (BPW) (pH 7.2) and apple juice (pH 3.5; 11.8 °Brix) was investigated in this study. BPW and apple juice were treated at different temperatures (55°C, 58°C, and 60°C) and for different times (0, 10, 20, 25, and 30 s) by ohmic heating compared with conventional heating. The electric field strength was fixed at 30 V/cm and 60 V/cm for BPW and apple juice, respectively. Bacterial reduction resulting from ohmic heating was significantly different (P < 0.05) from that resulting from conventional heating at 58°C and 60°C in BPW and at 55°C, 58°C, and 60°C in apple juice for intervals of 0, 10, 20, 25, and 30 s. These results show that electric field-induced ohmic heating led to additional bacterial inactivation at sublethal temperatures. Transmission electron microscopy (TEM) observations and the propidium iodide (PI) uptake test were conducted after treatment at 60°C for 0, 10, 20, 25 and 30 s in BPW to observe the effects on cell permeability due to electroporation-caused cell damage. PI values when ohmic and conventional heating were compared were significantly different (P < 0.05), and these differences increased with increasing levels of inactivation of three food-borne pathogens. These results demonstrate that ohmic heating can more effectively reduce bacterial populations at reduced temperatures and shorter time intervals, especially in acidic fruit juices such as apple juice. Therefore, loss of quality can be minimized in a pasteurization process incorporating ohmic heating. PMID:23995939

  3. Effect of electropermeabilization by ohmic heating for inactivation of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in buffered peptone water and apple juice.

    PubMed

    Park, Il-Kyu; Kang, Dong-Hyun

    2013-12-01

    The effect of electric field-induced ohmic heating for inactivation of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in buffered peptone water (BPW) (pH 7.2) and apple juice (pH 3.5; 11.8 °Brix) was investigated in this study. BPW and apple juice were treated at different temperatures (55°C, 58°C, and 60°C) and for different times (0, 10, 20, 25, and 30 s) by ohmic heating compared with conventional heating. The electric field strength was fixed at 30 V/cm and 60 V/cm for BPW and apple juice, respectively. Bacterial reduction resulting from ohmic heating was significantly different (P<0.05) from that resulting from conventional heating at 58°C and 60°C in BPW and at 55°C, 58°C, and 60°C in apple juice for intervals of 0, 10, 20, 25, and 30 s. These results show that electric field-induced ohmic heating led to additional bacterial inactivation at sublethal temperatures. Transmission electron microscopy (TEM) observations and the propidium iodide (PI) uptake test were conducted after treatment at 60°C for 0, 10, 20, 25 and 30 s in BPW to observe the effects on cell permeability due to electroporation-caused cell damage. PI values when ohmic and conventional heating were compared were significantly different (P<0.05), and these differences increased with increasing levels of inactivation of three food-borne pathogens. These results demonstrate that ohmic heating can more effectively reduce bacterial populations at reduced temperatures and shorter time intervals, especially in acidic fruit juices such as apple juice. Therefore, loss of quality can be minimized in a pasteurization process incorporating ohmic heating. PMID:23995939

  4. Interaction of the carbon monoxide-releasing molecule Ru(CO)3Cl(glycinate) (CORM-3) with Salmonella enterica serovar Typhimurium: in situ measurements of carbon monoxide binding by integrating cavity dual-beam spectrophotometry.

    PubMed

    Rana, Namrata; McLean, Samantha; Mann, Brian E; Poole, Robert K

    2014-12-01

    Carbon monoxide (CO) is a toxic gas that binds to haems, but also plays critical signalling and cytoprotective roles in mammalian systems; despite problems associated with systemic delivery by inhalation of the gas, it may be employed therapeutically. CO delivered to cells and tissues by CO-releasing molecules (CO-RMs) has beneficial and toxic effects not mimicked by CO gas; CO-RMs are also attractive candidates as novel antimicrobial agents. Salmonella enterica serovar Typhimurium is an enteropathogen causing gastroenteritis in humans. Recent studies have implicated haem oxygenase-1 (HO-1), the protein that catalyses the degradation of haem into biliverdin, free iron and CO, in the host immune response to Salmonella infection. In several studies, CO administration via CO-RMs elicited many of the protective roles of HO-1 induction and so we investigated the effects of a well-characterized water-soluble CO-RM, Ru(CO)3Cl(glycinate) (CORM-3), on Salmonella. CORM-3 exhibits toxic effects at concentrations significantly lower than those reported to cause toxicity to RAW 264.7 macrophages. We demonstrated here, through oxyhaemoglobin assays, that CORM-3 did not release CO spontaneously in phosphate buffer, buffered minimal medium or very rich medium. CORM-3 was, however, accumulated to high levels intracellularly (as shown by inductively coupled plasma MS) and released CO inside cells. Using growing Salmonella cultures without prior concentration, we showed for the first time that sensitive dual-beam integrating cavity absorption spectrophotometry can detect directly the CO released from CORM-3 binding in real-time to haems of the bacterial electron transport chain. The toxic effects of CO-RMs suggested potential applications as adjuvants to antibiotics in antimicrobial therapy. PMID:25085864

  5. The role of QseC quorum-sensing sensor kinase in colonization and norepinephrine-enhanced motility of Salmonella enterica serovar Typhirmurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcriptional analysis of Salmonella enterica serovar Typhimurium in the presence of the mammalian hormone Norepinephrine (NE) revealed up-regulation of chemotaxis and motility genes. Motility assays confirmed enhanced motility of wild-type S. Typhimurium in the presence of NE that could be block...

  6. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Mishmarhaemek Isolated from Bovine Feces

    PubMed Central

    Cooper, Ashley; Lambert, Dominic; Koziol, Adam G.; Seyer, Karine

    2015-01-01

    Salmonella enterica subsp. enterica serovar Mishmarhaemek is a Gram-negative, non-spore-forming, rod-shaped bacterium implicated in human clinical disease. Here, we report a 4.8-Mbp draft genome sequence of a nalidixic acid-resistant isolate of S. serovar Mishmarhaemek. PMID:26472847

  7. Salmonella enterica Typhimurium infection causes metabolic changes in chicken muscle involving AMPK, fatty acid and insulin/mTOR signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (ST) infection of chickens more than a few days old results in asymptomatic cecal colonization with persistent shedding of bacteria. We hypothesized that while the bacteria colonize and persist locally in the cecum, it has systemic effects influencing the phy...

  8. Virulence of Broad- and Narrow-Host-Range Salmonella enterica Serovars in the Streptomycin-Pretreated Mouse Model

    PubMed Central

    Suar, Mrutyunjay; Jantsch, Jonathan; Hapfelmeier, Siegfried; Kremer, Marcus; Stallmach, Thomas; Barrow, Paul A.; Hardt, Wolf-Dietrich

    2006-01-01

    Salmonella enterica subspecies I serovars are common bacterial pathogens causing diseases ranging from enterocolitis to systemic infections. Some serovars are adapted to specific hosts, whereas others have a broad host range. The molecular mechanisms defining the virulence characteristics and the host range of a given S. enterica serovar are unknown. Streptomycin pretreated mice provide a surrogate host model for studying molecular aspects of the intestinal inflammation (colitis) caused by serovar Typhimurium (S. Hapfelmeier and W. D. Hardt, Trends Microbiol. 13:497-503, 2005). Here, we studied whether this animal model is also useful for studying other S. enterica subspecies I serovars. All three tested strains of the broad-host-range serovar Enteritidis (125109, 5496/98, and 832/99) caused pronounced colitis and systemic infection in streptomycin pretreated mice. Different levels of virulence were observed among three tested strains of the host-adapted serovar Dublin (SARB13, SD2229, and SD3246). Several strains of host restricted serovars were also studied. Two serovar Pullorum strains (X3543 and 449/87) caused intermediate levels of colitis. No intestinal inflammation was observed upon infection with three different serovar Paratyphi A strains (SARB42, 2804/96, and 5314/98) and one serovar Gallinarum strain (X3796). A second serovar Gallinarum strain (287/91) was highly virulent and caused severe colitis. This strain awaits future analysis. In conclusion, the streptomycin pretreated mouse model can provide an additional tool to study virulence factors (i.e., those involved in enteropathogenesis) of various S. enterica subspecies I serovars. Five of these strains (125109, 2229, 287/91, 449/87, and SARB42) are subject of Salmonella genome sequencing projects. The streptomycin pretreated mouse model may be useful for testing hypotheses derived from this genomic data. PMID:16369020

  9. The agricultural antibiotic carbadox induces prophage and antibiotic resistance gene transfer in multidrug-resistant salmonella enterica serovar typhimurium DT104

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-typhoidal Salmonella strains cause ~1 million cases of foodborne disease each year in the U.S. and are a leading cause of food-related deaths. The prevalence of multidrug-resistant (MDR) Salmonella serovars has increased over the last few decades, and infection with these strains has an increase...

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

    PubMed Central

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael

    2015-01-01

    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 flagellum-chemotaxis regulon between these clinically relevant pathogens. PMID:26056383

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

    PubMed

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael; Gal-Mor, Ohad

    2015-09-01

    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 flagellum-chemotaxis regulon between these clinically relevant pathogens. PMID:26056383

  12. Transfer of Salmonella enterica serovar Typhimurium from contaminated irrigation water to parsley is dependent on curli and cellulose, the biofilm matrix components.

    PubMed

    Lapidot, Anat; Yaron, Sima

    2009-03-01

    Enteric pathogens can contaminate fresh produce, and this contaminated produce can be a significant potential source of human illness. The objective of this study was to determine a possible mode of transfer of Salmonella Typhimurium from contaminated irrigation water to mature parsley plants and to investigate the role of bacterial cellulose and curli. Parsley plants were drip irrigated with water containing green fluorescent protein-labeled Salmonella Typhimurium. Stems and leaves were harvested 1 day after the third irrigation and examined for the presence of Salmonella Typhimurium. Three weeks after harvesting, the presence of Salmonella was again confirmed in the regrown plants. During this period, bacterial numbers on leaves declined from 4.1 (+/- 0.3) to 2.3 (+/- 0.1) log CFU g(-1) (P < 0.05). Numbers in the soil were constant (5 log CFU g(-1)). Results demonstrated the ability of Salmonella Typhimurium to transfer from irrigation water to the edible parts of the plants. Confocal laser scanning microscopic images revealed that Salmonella Typhimurium formed aggregates at a depth of 8 to 32 microm beneath the leaf surface. Penetration might be achieved through the roots or the phyllosphere. The importance of the bacterial cellulose and curli was determined by comparing the wild-type strain with its mutants, which lack the ability to synthesize cellulose and curli. Counts of the double mutant were 2-log higher in the soil but 1-log lower in the leaves (P < 0.05). Deletion of the agfBA gene (for curli) was more effective than deletion of bcsA (for cellulose). Thus, curli and cellulose play a role in the transfer or survival of Salmonella Typhimurium in the plant, as they do for plant pathogens. PMID:19343953

  13. Impacts of Salmonella enterica Serovar Typhimurium and Its speG Gene on the Transcriptomes of In Vitro M Cells and Caco-2 Cells

    PubMed Central

    Wang, Ke-Chuan; Huang, Chih-Hung; Huang, Ching-Jou

    2016-01-01

    Microfold or membranous (M) cells are specialized intestinal epithelial cells responsible for host immunity. The speG mutant of Salmonella Typhimurium (S. Typhimurium) is a nonreplicating strain within human cells to be a candidate vaccine vector for interacting with M cells. We conducted this study to identify the genes are differently expressed between in vitro M cells and Caco-2 cells, and to determine whether S. Typhimurium and speG affect the transcriptomes of both cell types. In vitro M cells and Caco-2 cells were infected with wild-type (WT) S. Typhimurium, its ΔspeG mutant, or none for 1 h for RNA microarrays; the transcriptomes among the 6 pools were pairwisely compared. Genetic loci encoding scaffold (e.g., HSCHR7_CTG4_4, HSCHR9_CTG9_35), long noncoding RNA, membrane-associated protein (PITPNB), neuron-related proteins (OR8D1, OR10G9, and NTNG2), and transporter proteins (MICU2 and SLC28A1) were significantly upregulated in uninfected M cells compared with uninfected Caco-2 cells; and their encoding proteins are promising M-cell markers. Significantly upregulated HSCHR7_CTG4_4 of uninfected in vitro M cells were speG-independently downregulated by S. Typhimurium infection that is a remarkable change representing an important but unreported characteristic of M cells. The immune responses of in vitro M cells and Caco-2 cells can differ and reply on speG or not, with speG-dependent regulation of KYL4, SCTR, IL6, TNF, and CELF4 in Caco-2 cells, JUN, KLF6, and KCTD11 in M cells, or speG-independent modulation of ZFP36 in both cells. This study facilitates understanding of the immune responses of in vitro M cells after administering the S. Typhimurium ΔspeG mutant as a future vaccine vector. PMID:27064787

  14. RNA-seq analysis of prophage induction in multidrug-resistant salmonella enterica serovar typhimurium DT104 following exposure to the agricultural antibiotic carbadox

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-typhoidal Salmonella is a leading cause of U.S. foodborne disease and food-related deaths. Multidrug-resistant (MDR) Salmonella Typhimurium DT104 contains 5 prophages in the genome that may be induced to produce phage under various environmental conditions, including antibiotic exposure. We inve...

  15. Multidrug-Resistant Salmonella enterica Serovar Infantis, Israel

    PubMed Central

    Valinsky, Lea; Weinberger, Miriam; Guy, Sara; Jaffe, Joseph; Schorr, Yosef Ilan; Raisfeld, Abraham; Agmon, Vered; Nissan, Israel

    2010-01-01

    To determine whether rapid emergence of Salmonella enterica serovar Infantis in Israel resulted from an increase in different biotypes or spread of 1 clone, we characterized 87 serovar Infantis isolates on the genotypic and phenotypic levels. The emerging strain comprised 1 genetic clone with a distinct pulsed-field gel electrophoresis profile and a common antimicrobial drug resistance pattern. PMID:21029536

  16. Characterization of Virulence-Associated Genes, Antimicrobial Resistance Genes, and Class 1 Integrons in Salmonella enterica serovar Typhimurium Isolates from Chicken Meat and Humans in Egypt.

    PubMed

    Ahmed, Heba A; El-Hofy, Fatma I; Shafik, Saleh M; Abdelrahman, Mahmoud A; Elsaid, Gamilat A

    2016-06-01

    Foodborne pathogens are leading causes of illness especially in developing countries. The current study aimed to characterize virulence-associated genes and antimicrobial resistance in 30 Salmonella Typhimurium isolates of chicken and human origin at Mansoura, Egypt. The results showed that invA, avrA, mgtC, stn, and bcfC genes were identified in all the examined isolates, while 96.7% and 6.7% were positive for sopB and pef genes, respectively. The highest resistance frequencies of the isolates were to chloramphenicol and trimethoprim-sulfamethoxazole (73.3%, each), followed by streptomycin (56.7%), tetracycline and ampicillin (53.3%, each), and gentamicin (30%). However, only 2.7% of the isolates were resistant to cefotaxime and ceftriaxone each. Different resistance-associated genes, including blaTEM, aadB, aadC, aadA1, aadA2, floR, tetA(A), tetA(B), and sul1, were identified in Salmonella Typhimurium isolates with the respective frequencies of 53.3%, 6.7%, 23.3%, 46.7%, 63.3%, 73.3%, 60%, 20%, and 96.7%. None of the isolates was positive for blaSHV, blaOXA, and blaCMY genes. The results showed that the intI1 gene was detected in 24 (80%) of the examined Salmonella Typhimurium isolates. Class 1 integrons were found in 19 (79.2%) isolates that were intI1 positive. Seven integron profiles (namely: P-I to P-VII) were identified with P-V (gene cassette dfrA15, aadA2), the most prevalent profile. To the best of our knowledge, this is the first study to characterize the unusual gene cassette array dfrA12-OrfF-aadA27 from Salmonella Typhimurium isolates in Egypt. PMID:26977940

  17. The Genomic Blueprint of Salmonella enterica subspecies enterica serovar Typhi P-stx-12

    PubMed Central

    Ong, Su Yean; Pratap, Chandra Bhan; Wan, Xuehua; Hou, Shaobin; Rahman, Ahmad Yamin Abdul; Saito, Jennifer A.; Nath, Gopal; Alam, Maqsudul

    2013-01-01

    Salmonella enterica subspecies enterica serovar Typhi is a rod-shaped, Gram-negative, facultatively anaerobic bacterium. It belongs to the family Enterobacteriaceae in the class Gammaproteobacteria, and has the capability of residing in the human gallbladder by forming a biofilm and hence causing the person to become a typhoid carrier. Here we present the complete genome of Salmonella enterica subspecies enterica serotype Typhi strain P-stx-12, which was isolated from a chronic carrier in Varanasi, India. The complete genome comprises a 4,768,352 bp chromosome with a total of 98 RNA genes, 4,691 protein-coding genes and a 181,431 bp plasmid. Genome analysis revealed that the organism is closely related to Salmonella enterica serovar Typhi strain Ty2 and Salmonella enterica serovar Typhi strain CT18, although their genome structure is slightly different. PMID:24019994

  18. Pyroptosis and adaptive immunity mechanisms are promptly engendered in mesenteric lymph-nodes during pig infections with Salmonella enterica serovar Typhimurium

    PubMed Central

    2013-01-01

    In this study, we explored the transcriptional response and the morphological changes occurring in porcine mesenteric lymph-nodes (MLN) along a time course of 1, 2 and 6 days post infection (dpi) with Salmonella Typhimurium. Additionally, we analysed the expression of some Salmonella effectors in tissue to complete our view of the processes triggered in these organs upon infection. The results indicate that besides dampening apoptosis, swine take advantage of the flagellin and prgJ expression by Salmonella Typhimuriun to induce pyroptosis in MLN, preventing bacterial dissemination. Furthermore, cross-presentation of Salmonella antigens was inferred as a mechanism that results in a rapid clearance of pathogen by cytotoxic T cells. In summary, although the Salmonella Typhimurium strain employed in this study was able to express some of its major virulence effectors in porcine MLN, a combination of early innate and adaptive immunity mechanisms might overcome virulence strategies employed by the pathogen, enabling the host to protect itself against bacterial spread beyond gut-associated lymph-nodes. Interestingly, we deduced that clathrin-mediated endocytosis could contribute to mechanisms of pathogen virulence and/or host defence in MLN of Salmonella infected swine. Taken together, our results are useful for a better understanding of the critical protective mechanisms against Salmonella that occur in porcine MLN to prevent the spread of infection beyond the intestine. PMID:24308825

  19. Prevalence of Salmonella Isolates from Chicken and Pig Slaughterhouses and Emergence of Ciprofloxacin and Cefotaxime Co-Resistant S. enterica Serovar Indiana in Henan, China

    PubMed Central

    Bai, Li; Lan, Ruiting; Zhang, Xiuli; Cui, Shenghui; Xu, Jin; Guo, Yunchang; Li, Fengqin; Zhang, Ding

    2015-01-01

    The prevalence of Salmonella from chicken and pig slaughterhouses in Henan, China and antimicrobial susceptibility of these isolates to antibiotics was determined. From 283 chicken samples and 240 pig samples collected, 128 and 70 Salmonella isolates were recovered with an isolation rate of 45.2 and 29.2% respectively. The predominant serovars in chicken samples were S. enterica serovar Enteritidis, S. enterica serovar Hadar and S. enterica serovar Indiana, while those in pig samples were S. enterica serovar Typhimurium, S. enterica serovar Derby and S. enterica serovar Enteritidis. Resistance to ciprofloxacin was 8.6 and 10.0% for isolates from chickens and pigs respectively, whereas resistance to cefotaxime was 5.5 and 8.6%, respectively. Multidrug resistance (resistance to three or more classes of antimicrobial agent) was markedly higher in pig isolates (57.1%) than in chicken isolates (39.8%). Of particular concern was the detection of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana isolates, which pose risk to public health. All 16 S. enterica serovar Indiana isolates detected were resistant to ciprofloxacin, among which 11 were co-resistant to cefotaxime. The S. enterica serovar Indiana isolates accumulated point mutations in quinolone resistance determination regions of gyrA (S83F/D87G or S83F/D87N) and parC (T57S/S80R). Two plasmid mediated quinolone resistant determinants were found with aac (6')-Ib-cr and oqxAB in 16 and 12 S. enterica serovar Indiana isolates respectively. Cefotaxime-resistance of S. enterica serovar Indiana was associated with the acquisition of a blaCTX-M-65 gene. The potential risk of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana infection is a significant concern due to limited alternative treatment options. Reduction of Salmonella in chicken and pig slaughterhouses, in particular, ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana will be an important measure to reduce

  20. Inactivation kinetics of Listeria monocytogenes and Salmonella enterica serovar Typhimurium on fresh-cut bell pepper treated with slightly acidic electrolyzed water combined with ultrasound and mild heat.

    PubMed

    Luo, Ke; Oh, Deog-Hwan

    2016-02-01

    The goal of this study was to enhance the antimicrobial effect of slightly acidic electrolyzed water (SAEW) through addition of synergistic treatment with ultrasound (US) and mild heat treatment in order to improve the microbial safety of fresh-cut bell pepper. To evaluate the synergistic effects, the Weibull model was used to mathematically measure the effectiveness of the individual and combined treatments against Listeria monocytogenes and Salmonella Typhimurium on the pepper. The combined treatment (SAEW+US+60 °C) resulted in the TR values of 0.04 and 0.09 min for L. monocytogenes and S. Typhimurium, respectively, as consequence of the minimum value. Subsequently, texture analysis was carried out to test the potential effect on quality of the samples due to the involved mild heat and ultrasound treatment. When compared to the control, there was no significant change (p ≥ 0.05) in the texture (color and hardness) of the samples that were treated by 1 min of the combined treatment (SAEW+US+60 °C) during storage at 4 °C for 7 days. This combined treatment achieved approximately 3.0 log CFU/g reduction in the two pathogens. The results demonstrate that the involved hurdle factors which are ultrasound and mild heat achieved the synergistic effect of SAEW against the two pathogens. According to the results of texture analysis, 1 min of SAEW+US+60 °C is the optimal condition due to without negative influence on the quality of the samples during the storage. The optimal condition shows the enhanced antimicrobial effect of SAEW and enables to improve microbial safety of fresh bell pepper in food industry as a consequence of hurdle approach. PMID:26678144

  1. Mapping B-cell responses to Salmonella enterica serovars Typhimurium and Enteritidis in chickens for the discrimination of infected from vaccinated animals.

    PubMed

    Naqid, Ibrahim A; Owen, Jonathan P; Maddison, Ben C; Spiliotopoulos, Anastasios; Emes, Richard D; Warry, Andrew; Flynn, Robin J; Martelli, Francesca; Gosling, Rebecca J; Davies, Robert H; La Ragione, Roberto M; Gough, Kevin C

    2016-01-01

    Serological surveillance and vaccination are important strategies for controlling infectious diseases of food production animals. However, the compatibility of these strategies is limited by a lack of assays capable of differentiating infected from vaccinated animals (DIVA tests) for established killed or attenuated vaccines. Here, we used next generation phage-display (NGPD) and a 2-proportion Z score analysis to identify peptides that were preferentially bound by IgY from chickens infected with Salmonella Typhimurium or S. Enteritidis compared to IgY from vaccinates, for both an attenuated and an inactivated commercial vaccine. Peptides that were highly enriched against IgY from at least 4 out of 10 infected chickens were selected: 18 and 12 peptides for the killed and attenuated vaccines, respectively. The ten most discriminatory peptides for each vaccine were identified in an ELISA using a training set of IgY samples. These peptides were then used in multi-peptide assays that, when analysing a wider set of samples from infected and vaccinated animals, diagnosed infection with 100% sensitivity and specificity. The data describes a method for the development of DIVA assays for conventional attenuated and killed vaccines. PMID:27510219

  2. Mapping B-cell responses to Salmonella enterica serovars Typhimurium and Enteritidis in chickens for the discrimination of infected from vaccinated animals

    PubMed Central

    Naqid, Ibrahim A.; Owen, Jonathan P.; Maddison, Ben C.; Spiliotopoulos, Anastasios; Emes, Richard D.; Warry, Andrew; Flynn, Robin J.; Martelli, Francesca; Gosling, Rebecca J.; Davies, Robert H.; La Ragione, Roberto M.; Gough, Kevin C.

    2016-01-01

    Serological surveillance and vaccination are important strategies for controlling infectious diseases of food production animals. However, the compatibility of these strategies is limited by a lack of assays capable of differentiating infected from vaccinated animals (DIVA tests) for established killed or attenuated vaccines. Here, we used next generation phage-display (NGPD) and a 2-proportion Z score analysis to identify peptides that were preferentially bound by IgY from chickens infected with Salmonella Typhimurium or S. Enteritidis compared to IgY from vaccinates, for both an attenuated and an inactivated commercial vaccine. Peptides that were highly enriched against IgY from at least 4 out of 10 infected chickens were selected: 18 and 12 peptides for the killed and attenuated vaccines, respectively. The ten most discriminatory peptides for each vaccine were identified in an ELISA using a training set of IgY samples. These peptides were then used in multi-peptide assays that, when analysing a wider set of samples from infected and vaccinated animals, diagnosed infection with 100% sensitivity and specificity. The data describes a method for the development of DIVA assays for conventional attenuated and killed vaccines. PMID:27510219

  3. Whole-genome sequencing of Salmonella enterica subsp. enterica serovar Cubana strains isolated from agricultural sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report draft genomes of Salmonella enterica subsp. enterica Serovar Cubana strain CVM42234 isolated from chick feed in 2012 and Salmonella Cubana strain 76814 isolated from swine in 2004. The genome sizes are 4,975,046 and 4,936,251 base pairs, respectively....

  4. Complete Genome Sequence and Methylome of Salmonella enterica subsp. enterica Cerro, a Frequent Dairy Cow Serovar

    PubMed Central

    Haley, Bradd J.; Pirone, Cary; Muruvanda, Tim; Brown, Eric; Allard, Marc; Karns, Jeffrey S.

    2016-01-01

    Salmonella enterica subsp. enterica serovar Cerro is an infrequent pathogen of humans and other mammals but is frequently isolated from the hindgut of asymptomatic cattle in the United States. To further understand the genomic determinants of S. Cerro specificity for the bovine hindgut, the genome of isolate CFSAN001588 was fully sequenced and deposited in the GenBank database. PMID:26823571

  5. Whole-Genome Sequencing of Salmonella enterica subsp. enterica Serovar Ouakam Isolated from Ground Turkey

    PubMed Central

    Marasini, Daya; Abo-Shama, Usama H.

    2016-01-01

    In this report, we announce the first whole-genome sequencing of Salmonella enterica subsp. enterica serovar Ouakam strain GNT-01, isolated from ground turkey retail meat. The strain has a chromosome of 5,088,451 bp long, with a G+C content of 52.3%, and a plasmid of 109,715 bp. PMID:26798110

  6. Complete genome sequence of salmonella enterica subsp. enterica Serovar Thompson Strain RM6836

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson (S. Thompson) strain RM6836 was isolated from lettuce in 2002. We report the complete sequence and annotation of the genome of S. Thompson strain RM6836. This is the first reported complete genome sequence for S. Thompson and will provide a point ...

  7. Characterization of FimH adhesins expressed by Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum: reconstitution of mannose-binding properties by single amino acid substitution.

    PubMed

    Kisiela, Dagmara; Sapeta, Anna; Kuczkowski, Maciej; Stefaniak, Tadeusz; Wieliczko, Alina; Ugorski, Maciej

    2005-09-01

    Recombinant FimH adhesins of type 1 fimbriae from Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum, in contrast to those of Salmonella enterica serovar Typhimurium, did not bind to high-mannose oligosaccharides or to human colon carcinoma HT-29 cells. However, mutated FimH proteins from biovar Gallinarum and biovar Pullorum, in which the isoleucine at position 78 was replaced by the threonine found in S. enterica serovar Typhimurium, bound well to glycoproteins carrying high-mannose oligosaccharides and colon carcinoma cells. The loss of sugar-binding properties by biovar Gallinarum and biovar Pullorum FimH adhesins, which are a part of the type 1 fimbriae, is most probably the result of a single T78I mutation, as was proven by site-directed mutagenesis of FimH proteins. PMID:16113346

  8. Characterization of a pore-forming cytotoxin expressed by Salmonella enterica serovars typhi and paratyphi A.

    PubMed

    Oscarsson, Jan; Westermark, Marie; Löfdahl, Sven; Olsen, Björn; Palmgren, Helena; Mizunoe, Yoshimitsu; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2002-10-01

    Cytolysin A (ClyA) is a pore-forming cytotoxic protein encoded by the clyA gene that has been characterized so far only in Escherichia coli. Using DNA sequence analysis and PCR, we established that clyA is conserved in the human-specific typhoid Salmonella enterica serovars Typhi and Paratyphi A and that the entire clyA gene locus is absent in many other S. enterica serovars, including Typhimurium. The gene products, designated ClyA(STy) and ClyA(SPa), show >/=90% amino acid identity to E. coli cytolysin A, ClyA(EC), and they are immunogenically related. The Salmonella proteins showed a pore-forming activity and are hence functional homologues to ClyA(EC). The chromosomal clyA(STy) gene locus was expressed at detectable levels in the serovar Typhi strains S2369/96 and S1112/97. Furthermore, in the serovar Typhi vaccine strain Ty21a, expression of clyA(STy) reached phenotypic levels, as detected on blood agar plates. The hemolytic phenotype was abolished by the introduction of an in-frame deletion in the clyA(STy) chromosomal locus of Ty21a. Transcomplementation of the mutant with a cloned clyA(STy) gene restored the hemolytic phenotype. To our knowledge, Ty21a is the first reported phenotypically hemolytic Salmonella strain in which the genetic determinant has been identified. PMID:12228306

  9. Limited Genetic Diversity in Salmonella enterica Serovar Enteritidis PT13

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis has emerged as a significant food-borne pathogen throughout the world and it is commonly characterized by phage typing (PT). In Canada, PT4, 8 and 13 are the predominant PTs. Epidemiological subtyping of Salmonella is typically done by PFGE but plasmid profil...

  10. Method for the detection of Salmonella enterica serovar Enteritidis

    DOEpatents

    Agron, Peter G.; Andersen, Gary L.; Walker, Richard L.

    2008-10-28

    Described herein is the identification of a novel Salmonella enterica serovar Enteritidis locus that serves as a marker for DNA-based identification of this bacterium. In addition, three primer pairs derived from this locus that may be used in a nucleotide detection method to detect the presence of the bacterium are also disclosed herein.

  11. Limited genetic diversity in Salmonella enterica Serovar Enteritidis PT13

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis has emerged as a significant foodborne pathogen throughout the world and is commonly characterized by phage typing. In Canada phage types (PT) 4, 8 and 13 predominate and in 2005 a large foodborne PT13 outbreak occurred in the province of Ontario. The ability ...

  12. Effects of prior coinfection with different Salmonella serovars on the progression of a Salmonella enterica serovar enteritidis infection in hens undergoing induced molt.

    PubMed

    Holt, Peter S; Gast, Richard K

    2004-01-01

    Four trials were conducted to evaluate whether prior infection with Salmonella enterica serovar typhimurium (S. typhimurium) or Salmonella enterica serovar muenchen (S. muenchen) would modify the severity or the transmission of Salmonella enterica serovar enteritidis (S. enteritidis) challenge in hens undergoing molt via feed withdrawal. Hens were separated into two groups where one group received a prior S. typhimurium or S. muenchen infection, whereas the other group remained untreated until S. enteritidis challenge. In trials 1 and 2, one group of hens was infected with S. typhimurium 5 days prior to feed withdrawal. Both groups of hens were then challenged with S. enteritidis on day 4 post feed withdrawal. In trials 3 and 4, one group of hens received S. typhimurium or S. muenchen, respectively, 1 day after feed was withdrawn. Transmission of S. enteritidis was evaluated by challenging the center hen in rows of 11 hens per row with S. enteritidis at 4 days post feed withdrawal and following the progression of the S. enteritidis down the row of hens over time. In trials 1 and 2, where hens received S. typhimurium 5 days prior to feed withdrawal, shedding of the S. enteritidis challenge was significantly reduced in hens on day 10 postchallenge in trial 1 and on days 3 and 10 postchallenge in trial 2 compared with the hens subjected only to the molt procedure. Significantly fewer S. enteritidis were recovered in livers and spleens at day 9 postchallenge in trial 2 from hens receiving the prior S. typhimurium infection. In trial 3, where hens received S. typhimurium 1 day after feed withdrawal, S. enteritidis transmission was significantly reduced in these hens on days 3, 10, and 24 postchallenge. In trial 4, similar in methodology to trial 3 except that, rather than S. typhimurium, hens received S. muenchen, a Salmonella organism totally lacking any antigen cross-reactive with S. enteritidis, S. enteritidis transmission was significantly reduced on days 3, 10, 17

  13. Involvement of a Salmonella Genomic Island 1 Gene in the Rumen Protozoan-Mediated Enhancement of Invasion for Multiple-Antibiotic-Resistant Salmonella enterica Serovar Typhimurium▿

    PubMed Central

    Carlson, Steve A.; Sharma, Vijay K.; McCuddin, Zoe P.; Rasmussen, Mark A.; Franklin, Sharon K.

    2007-01-01

    Multiple-antibiotic-resistant Salmonella enterica serotype Typhimurium is a food-borne pathogen that may be more virulent than related strains lacking the multiresistance phenotype. Salmonella enterica serotype Typhimurium phage type DT104 is the most prevalent of these multiresistant/hypervirulent strains. Multiresistance in DT104 is conferred by an integron structure, designated Salmonella genomic island 1 (SGI1), while we recently demonstrated DT104 hyperinvasion mediated by rumen protozoa (RPz) that are normal flora of cattle. Hyperinvasion was also observed in other Salmonella strains, i.e., other S. enterica serovar Typhimurium phage types and other S. enterica serovars, like S. enterica serovar Infantis, possessing SGI1, while DT104 strains lacking SGI1 were not hyperinvasive. Herein we attempted to identify SGI1 genes involved in the RPz-mediated hyperinvasion of Salmonella strains bearing SGI1. Transposon mutagenesis, coupled with a novel reporter system, revealed the involvement of an SGI1 gene previously designated SO13. Disruption of SO13 expression led to an abrogation of hyperinvasion as assessed by tissue culture invasion assays and by bovine challenge experiments. However, hyperinvasion was not observed in non-SGI1-bearing strains of Salmonella engineered to express SO13. That is, SO13 and another SGI1 gene(s) may coordinately upregulate invasion in DT104 exposed to RPz. PMID:17145942

  14. Complete and Closed Genome Sequences of 10 Salmonella enterica subsp. enterica Serovar Anatum Isolates from Human and Bovine Sources

    PubMed Central

    Nguyen, Scott V.; Bono, James L.; Smith, Timothy P. L.; Fields, Patricia I.; Dinsmore, Blake A.; Santovenia, Monica; Kelley, Christy M.; Wang, Rong; Bosilevac, Joseph M.; Harhay, Gregory P.

    2016-01-01

    Salmonella enterica is an important pathogen transmitted by numerous vectors. Genomic comparisons of Salmonella strains from disparate hosts have the potential to further our understanding of mechanisms underlying host specificities and virulence. Here, we present the closed genome and plasmid sequences of 10 Salmonella enterica subsp. enterica serovar Anatum isolates from bovine and human sources. PMID:27257192

  15. Complete and Closed Genome Sequences of 10 Salmonella enterica subsp. enterica Serovar Anatum Isolates from Human and Bovine Sources.

    PubMed

    Nguyen, Scott V; Harhay, Dayna M; Bono, James L; Smith, Timothy P L; Fields, Patricia I; Dinsmore, Blake A; Santovenia, Monica; Kelley, Christy M; Wang, Rong; Bosilevac, Joseph M; Harhay, Gregory P

    2016-01-01

    Salmonella enterica is an important pathogen transmitted by numerous vectors. Genomic comparisons of Salmonella strains from disparate hosts have the potential to further our understanding of mechanisms underlying host specificities and virulence. Here, we present the closed genome and plasmid sequences of 10 Salmonella enterica subsp. enterica serovar Anatum isolates from bovine and human sources. PMID:27257192

  16. Complete Genome Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica Serovar Thompson Associated with Cilantro

    PubMed Central

    Huynh, Steven; Gorski, Lisa; Cooper, Kerry K.; Miller, William G.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH-99A2345) are associated with a 1999 outbreak in contaminated cilantro. We report here the complete genome sequences and annotation of these two S. Thompson strains. These genomes are distinct and provide additional data for our understanding of S. enterica. PMID:26586897

  17. Complete Genome Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica Serovar Thompson Associated with Cilantro.

    PubMed

    Parker, Craig T; Huynh, Steven; Gorski, Lisa; Cooper, Kerry K; Miller, William G

    2015-01-01

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH-99A2345) are associated with a 1999 outbreak in contaminated cilantro. We report here the complete genome sequences and annotation of these two S. Thompson strains. These genomes are distinct and provide additional data for our understanding of S. enterica. PMID:26586897

  18. Chromosome-Mediated Multidrug Resistance in Salmonella enterica Serovar Typhi

    PubMed Central

    Alam, Munirul; Kuo, Jung-Che; Liu, Yen-Yi; Wang, Pei-Jen

    2014-01-01

    A salmonella genomic island, designated SGI11, was found in 18 of 26 multidrug-resistant Salmonella enterica serovar Typhi isolates from Bangladesh. SGI11 was an IS1 composite transposon and carried 7 resistance genes that conferred resistance to 5 first-line antimicrobials. Eleven of the 18 SGI11-carrying S. Typhi isolates had developed resistance to high levels of ciprofloxacin. PMID:25367917

  19. Serovar distribution, antimicrobial resistance profiles, and PFGE typing of Salmonella enterica strains isolated from 2007–2012 in Guangdong, China

    PubMed Central

    2014-01-01

    Background Salmonella enterica includes the major serovars associated with human salmonellosis. In this study, 1764 clinical Salmonella enterica isolates from diarrhea outpatients were collected from fifteen cities in Guangdong province, China, between 2007 and 2012. These isolates represent all of the Salmonella isolates collected from the province during that period. Methods The isolates were characterized by serovar determination, antimicrobial susceptibility tests and PFGE fingerprint typing. Results The serovar distribution results demonstrated that Salmonella Typhimurium (n = 523, 29.65%) and Salmonella 4,5,12:i:- (n = 244, 13.83%) are the most common serovars causing infant salmonellosis, whereas Salmonella Enteritidis (n = 257, 14.57%) mainly causes human salmonellosis in adults. The serovar shift from Salmonella Enteritidis to Salmonella Typhimurium occurred in 2008. Antimicrobial susceptibility data showed a high burden of multidrug resistance (MDR) (n = 1128, 56.58%), and a 20%-30% increase in the number of isolates resistant to ciprofloxacin (n = 142, 8.05%) and third-generation cephalosporins (n = 88, 4.99%) from 2007–2012. Only 9.97% of isolates (n = 176) were fully susceptible to all agents tested. A high burden of MDR was observed in Salmonella Typhimurium and Salmonella 4,5,12:i:- for all age groups, and a reduced susceptibility to third-generation cephalosporins and quinolones occurred particularly in infants (≤6 years). The dominant PFGE patterns were JPXX01.GD0004, JEGX01.GD0006-7 and JNGX01.GD0006-7. ACSSuT was the predominant MDR profile in the Salmonella Typhimurium & 4,5,12:i:- complexes, while ASSuT-Nal and ASSu-Nal were the major MDR profiles in Salmonella Enteritidis. The predominant PFGE patterns of the Salmonella Typhimurium & 4,5,12:i:- complexes and Salmonella Stanley were most prevalent in infants (≤6 years). However, no obvious relationship was observed between these PFGE profiles and geographic

  20. Genome-scale screening and validation of targets for identification of Salmonella enterica and serovar prediction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is the most common foodborne pathogen worldwide, with a great diversity of 2500 recognized serovars. Detection of S. enterica and its classification into serovars are essential for food safety surveillance and clinical diagnosis. Recently, the polymerase chain reaction (PCR) meth...

  1. Physiological and Immunological Regulations in Caenorhabditis elegans Infected with Salmonella enterica serovar Typhi.

    PubMed

    Sivamaruthi, Bhagavathi Sundaram; Balamurugan, Krishnaswamy

    2014-03-01

    Studies pertaining to Salmonella enterica serovar Typhimurium infection by utilizing model systems failed to mimic the essential aspects of immunity induced by Salmonella enterica serovar Typhi, as the determinants of innate immunity are distinct. The present study investigated the physiological and innate immune responses of S. Typhi infected Caenorhabditis elegans and also explored the Ty21a mediated immune enhancement in C. elegans. Ty21a is a known live vaccine for typhoidal infection in human beings. Physiological responses of C. elegans infected with S. Typhi assessed by survival and behavioral assays revealed that S. Typhi caused host mortality by persistent infection. However, Ty21a exposure to C. elegans was not harmful. Ty21a pre-exposed C. elegans, exhibited significant resistance against S. Typhi infection. Elevated accumulation of S. Typhi inside the infected host was observed when compared to Ty21a exposures. Transcript analysis of candidate innate immune gene (clec-60, clec-87, lys-7, ilys-3, scl-2, cpr-2, F08G5.6, atf-7, age-1, bec-1 and daf-16) regulations in the host during S. Typhi infection have been assessed through qPCR analysis to understand the activation of immune signaling pathways during S. Typhi infections. Gene silencing approaches confirmed that clec-60 and clec-87 has a major role in the defense system of C. elegans during S. Typhi infection. In conclusion, the study revealed that preconditioning of host with Ty21a protects against subsequent S. Typhi infection. PMID:24426167

  2. Pseudogenization of sopA and sopE2 is functionally linked and contributes to virulence of Salmonella enterica serovar Typhi.

    PubMed

    Valenzuela, L M; Hidalgo, A A; Rodríguez, L; Urrutia, I M; Ortega, A P; Villagra, N A; Paredes-Sabja, D; Calderón, I L; Gil, F; Saavedra, C P; Mora, G C; Fuentes, J A

    2015-07-01

    The difference in host range between Salmonella enterica serovar Typhimurium (S. Typhimurium) and S. enterica serovar Typhi (S. Typhi) can be partially attributed to pseudogenes. Pseudogenes are genomic segments homologous to functional genes that do not encode functional products due to the presence of genetic defects. S. Typhi lacks several protein effectors implicated in invasion or other important processes necessary for full virulence of S. Typhimurium. SopA and SopE2, effectors that have been lost by pseudogenization in S. Typhi, correspond to an ubiquitin ligase involved in cytokine production by infected cells, and to a guanine exchange factor necessary for invasion of epithelial cells, respectively. We hypothesized that sopA and/or sopE pseudogenization contributed to the virulence of S. Typhi. In this work, we found that S. Typhi expressing S. Typhimurium sopE2 exhibited a decreased invasion in different epithelial cell lines compared with S. Typhi WT. S. Typhimurium sopA completely abolished the hypo-invasive phenotype observed in S. Typhi expressing S. Typhimurium sopE2, suggesting that functional SopA and SopE2 participate concertedly in the invasion process. Finally, the expression of S. Typhimurium sopA and/or sopE2 in S. Typhi, determined changes in the secretion of IL-8 and IL-18 in infected epithelial cells. PMID:25913156

  3. Genome-Scale Screening and Validation of Targets for Identification of Salmonella enterica and Serovar Prediction.

    PubMed

    Zhou, Xiujuan; Zhang, Lida; Shi, Chunlei; Fratamico, Pina M; Liu, Bin; Paoli, George C; Dan, Xianlong; Zhuang, Xiaofei; Cui, Yan; Wang, Dapeng; Shi, Xianming

    2016-03-01

    Salmonella enterica is the most common foodborne pathogen worldwide, with 2,500 recognized serovars. Detection of S. enterica and its classification into serovars are essential for food safety surveillance and clinical diagnosis. The PCR method is useful for these applications because of its rapidity and high accuracy. We obtained 412 candidate detection targets for S. enterica using a comparative genomics mining approach. Gene ontology (GO) functional enrichment analysis of these candidate targets revealed that the GO term with the largest number of unigenes with known function (38 of 177, 21.5%) was significantly involved in pathogenesis (P < 10(-24)). All the candidate targets were then evaluated by PCR assays. Fifteen targets showed high specificity for the detection of S. enterica by verification with 151 S. enterica strains and 34 non-Salmonella strains. The phylogenetic trees of verified targets were highly comparable with those of housekeeping genes, especially for differentiating S. enterica strains into serovars. The serovar prediction ability was validated by sequencing one target (S9) for 39 S. enterica strains belonging to six serovars. Identical mutation sites existed in the same serovar, and different mutation sites were found in diverse serovars. Our findings revealed that 15 verified targets can be potentially used for molecular detection, and some of them can be used for serotyping of S. enterica strains. PMID:26939647

  4. Clinical and veterinary isolates of Salmonella enterica serovar Enteritidis defective in lipopolysaccharide O-chain polymerization

    SciTech Connect

    Guard-Petter, J.; Parker, C.T.; Asokan, K.; Carlson, R.W.

    1999-05-01

    Twelve human and chicken isolates of Salmonella enterica serovar Enteritidis belonging to phage types 4, 8, 13a, and 23 were characterized for variability in lipopolysaccharide (LPS) composition. Isolates were differentiated into two groups, i.e., those that lacked immunoreactive O-chain, termed rough isolates, and those that had immunoreactive O-chain, termed smooth isolates. Isolates within these groups could be further differentiated by LPS compositional differences as detected by gel electrophoresis and gas liquid chromatography of samples extracted with water, which yielded significantly more LPS in comparison to phenol-chloroform extraction. The rough isolates were of two types, the O-antigen synthesis mutants and the O-antigen polymerization (wzy) mutants. Smooth isolates were also of two types, one producing low-molecular-weight (LMW) LPS and the other producing high-molecular-weight (HMW) LPS. To determine the genetic basis for the O-chain variability of the smooth isolates, the authors analyzed the effects of a null mutation in the O-chain length determinant gene, wzz (cld) of serovar Typhimurium. This mutation results in a loss of HMW LPS; however, the LMW LPS of this mutant was longer and more glucosylated than that from clinical isolates of serovar Enteritidis. Cluster analysis of these data and of those from two previously characterized isogenic strains of serovar Enteritidis that had different virulence attributes indicated that glucosylation of HMW LPS (via oafR function) is variable and results in two types of HMW structures, one that is highly glucosylated and one that is minimally glucosylated. These results strongly indicate that naturally occurring variability in wzy, wzz, and oafR function can be used to subtype isolates of serovar Enteritidis during epidemiological investigations.

  5. Salmonella enterica Serovar Typhi conceals the invasion-associated type three secretion system from the innate immune system by gene regulation.

    PubMed

    Winter, Sebastian E; Winter, Maria G; Poon, Victor; Keestra, A Marijke; Sterzenbach, Torsten; Faber, Franziska; Costa, Luciana F; Cassou, Fabiane; Costa, Erica A; Alves, Geraldo E S; Paixão, Tatiane A; Santos, Renato L; Bäumler, Andreas J

    2014-07-01

    Delivery of microbial products into the mammalian cell cytosol by bacterial secretion systems is a strong stimulus for triggering pro-inflammatory host responses. Here we show that Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, tightly regulates expression of the invasion-associated type III secretion system (T3SS-1) and thus fails to activate these innate immune signaling pathways. The S. Typhi regulatory protein TviA rapidly repressed T3SS-1 expression, thereby preventing RAC1-dependent, RIP2-dependent activation of NF-κB in epithelial cells. Heterologous expression of TviA in S. enterica serovar Typhimurium (S. Typhimurium) suppressed T3SS-1-dependent inflammatory responses generated early after infection in animal models of gastroenteritis. These results suggest that S. Typhi reduces intestinal inflammation by limiting the induction of pathogen-induced processes through regulation of virulence gene expression. PMID:24992093

  6. Salmonella enterica Serovar Typhi Conceals the Invasion-Associated Type Three Secretion System from the Innate Immune System by Gene Regulation

    PubMed Central

    Winter, Sebastian E.; Winter, Maria G.; Poon, Victor; Keestra, A. Marijke; Sterzenbach, Torsten; Faber, Franziska; Costa, Luciana F.; Cassou, Fabiane; Costa, Erica A.; Alves, Geraldo E. S.; Paixão, Tatiane A.; Santos, Renato L.; Bäumler, Andreas J.

    2014-01-01

    Delivery of microbial products into the mammalian cell cytosol by bacterial secretion systems is a strong stimulus for triggering pro-inflammatory host responses. Here we show that Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, tightly regulates expression of the invasion-associated type III secretion system (T3SS-1) and thus fails to activate these innate immune signaling pathways. The S. Typhi regulatory protein TviA rapidly repressed T3SS-1 expression, thereby preventing RAC1-dependent, RIP2-dependent activation of NF-κB in epithelial cells. Heterologous expression of TviA in S. enterica serovar Typhimurium (S. Typhimurium) suppressed T3SS-1-dependent inflammatory responses generated early after infection in animal models of gastroenteritis. These results suggest that S. Typhi reduces intestinal inflammation by limiting the induction of pathogen-induced processes through regulation of virulence gene expression. PMID:24992093

  7. Salmonella serovars differentially stimulate bovine leukocyte responses in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The majority of Salmonella serovars cause no clinical signs in cattle, while some serovars, such as Salmonella enterica serovar Typhimurium (ST) and Dublin (SD), may cause severe disease. Mechanisms underlying the difference in pathogenesis between different serovars are not clear. The objective of ...

  8. Draft Genome Sequences of Salmonella enterica subsp. enterica Serovar Berta ATCC 8392 and a Nalidixic Acid-Resistant Isolate of This Strain

    PubMed Central

    Cooper, Ashley; Koziol, Adam G.; Carrillo, Catherine D.

    2016-01-01

    Salmonella enterica subspecies enterica serovar Berta has been isolated in multiple animal species and has been implicated in human disease. Here, we report a 4.7-Mbp draft genome sequence of S. enterica serovar Berta (ATCC strain 8392) and a nalidixic acid-resistant isolate derived from this strain. PMID:27103707

  9. Egg contamination by Salmonella serovar enteritidis following vaccination with Delta-aroA Salmonella serovar typhimurium.

    PubMed

    Parker, C; Asokan, K; Guard-Petter, J

    2001-02-01

    The efficacy of an aroA Salmonella serovar typhimurium modified live vaccine to decrease internal egg contamination after oral challenge of hens with egg-contaminating Salmonella serovar enteritidis was assessed. Challenge was with a mixed phenotype of S. enteritidis that had virulence characteristics previously associated with enhanced oral invasiveness and egg contamination in chickens. Immunized birds had fewer positive ovary/oviduct pools and lower cfu g(-1) cecal contents than did non-immunized birds, but the differences were not significant. The number of positive intestinal (duodenum, jejunum, ileum) and organ (spleen, kidney, liver) pools following challenge from each treatment group were equivalent. Most importantly, immunization did not decrease egg contamination. These results suggest that the ability of modified live vaccines to reduce internal egg contamination by S. serovar enteritidis can be assessed using characterized strains for challenge. PMID:11166998

  10. Complete genomic sequences of two outbreak strains of Salmonella enterica subsp. enterica serovar Thompson associated with cilantro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH -99A2345) are clinical isolates from 1999, putatively related to an outbreak in California from contaminated cilantro. We report the complete genome sequences and annotation of these two S. Thompson...

  11. Genome Sequences of Salmonella enterica subsp. enterica Serovar Lubbock Strains Isolated from Liver Abscesses of Feedlot Cattle

    PubMed Central

    Amachawadi, Raghavendra G.; Thomas, Milton

    2016-01-01

    The genome sequencing of 13 Salmonella enterica subsp. enterica serovar Lubbock strains isolated from liver abscesses of feedlot cattle is reported here. The availability of these genomes will help to further understand the etiologic role of Salmonella strains in liver abscesses of cattle and will serve as references in microbial trace-back studies to improve food safety. PMID:27151794

  12. The complete genome sequence and methylome of Salmonella enterica subsp. enterica serovar Cerro, a frequent dairy cow strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Cerro is an infrequent pathogen of humans and other mammals, but is frequently isolated from the hindgut of asymptomatic cattle in the United States. To further understand the genomic determinants of S. Cerro specificity for the bovine hindgut, the genome ...

  13. Complete Genomic Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica serovar Thompson Associated with Cilantro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH -99A2345) are clinical isolates from 1999, putatively related to an outbreak in California from contaminated cilantro. We report the complete genome sequences and annotation of these two S. Thompson...

  14. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen

    PubMed Central

    Hart, Peter J.; O’Shaughnessy, Colette M.; Siggins, Matthew K.; Bobat, Saeeda; Kingsley, Robert A.; Goulding, David A.; Crump, John A.; Reyburn, Hugh; Micoli, Francesca; Dougan, Gordon; Cunningham, Adam F.; MacLennan, Calman A.

    2016-01-01

    Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies. PMID:26741681

  15. Complete Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate B/SF/13/03/195 Associated with a Typhoid Carrier in Pasir Mas, Kelantan, Malaysia

    PubMed Central

    Sim, Kee-Shin; Mohd Nor, Fauziah; Mat Hussin, Hani; Hamzah, Wan Mansor; Najimudin, Nazalan

    2015-01-01

    We report here the complete genome sequence of Salmonella enterica subsp. enterica serovar Typhi B/SF/13/03/195 obtained from a typhoid carrier, who is a food handler in Pasir Mas, Kelantan. PMID:26564035

  16. Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate PM016/13 from Untreated Well Water Associated with a Typhoid Outbreak in Pasir Mas, Kelantan, Malaysia.

    PubMed

    Muhamad Harish, Salwani; Sim, Kee-Shin; Najimudin, Nazalan; Aziah, Ismail

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Even though it is a human-restricted pathogen, the bacterium is also isolated from environments such as groundwater and pond water. Here, we describe the genome sequence of the Salmonella enterica subsp. enterica serovar Typhi PM016/13 which was isolated from well water during a typhoid outbreak in Kelantan, Malaysia, in 2013. PMID:26564032

  17. Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate PM016/13 from Untreated Well Water Associated with a Typhoid Outbreak in Pasir Mas, Kelantan, Malaysia

    PubMed Central

    Sim, Kee-Shin; Najimudin, Nazalan

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Even though it is a human-restricted pathogen, the bacterium is also isolated from environments such as groundwater and pond water. Here, we describe the genome sequence of the Salmonella enterica subsp. enterica serovar Typhi PM016/13 which was isolated from well water during a typhoid outbreak in Kelantan, Malaysia, in 2013. PMID:26564032

  18. Analysis of Plasmid and Chromosomal DNA of Multidrug-Resistant Salmonella enterica Serovar Typhi from Asia

    PubMed Central

    Mirza, S.; Kariuki, S.; Mamun, K. Z.; Beeching, N. J.; Hart, C. A.

    2000-01-01

    Molecular analysis of chromosomal DNA from 193 multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates from 1990 to 1995 from Pakistan, Kuwait, Malaysia, Bangladesh, and India produced a total of five major different pulsed-field gel electrophoresis (PFGE) patterns. Even within a particular country MDR S. enterica serovar Typhi DNA was found to be in different PFGE groups. Similar self-transferable 98-MDa plasmids belonging to either incompatibility group incHI1 or incHI1/FIIA were implicated in the MDR phenotype in S. enterica serovar Typhi isolates from all the locations except Quetta, Pakistan, where the majority were of incFIA. A total of five different PFGE genotypes with six different plasmids, based on incompatibility and restriction endonuclease analysis groups, were found among these MDR S. enterica serovar Typhi isolates. PMID:10747124

  19. Analysis of the ArcA regulon in anaerobically grown Salmonella enterica sv. Typhimurium

    PubMed Central

    2011-01-01

    Background Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative pathogen that must successfully adapt to the broad fluctuations in the concentration of dissolved dioxygen encountered in the host. In Escherichia coli, ArcA (Aerobic Respiratory Control) helps the cells to sense and respond to the presence of dioxygen. The global role of ArcA in E. coli is well characterized; however, little is known about its role in anaerobically grown S. Typhimurium. Results We compared the transcriptional profiles of the virulent wild-type (WT) strain (ATCC 14028s) and its isogenic arcA mutant grown under anaerobic conditions. We found that ArcA directly or indirectly regulates 392 genes (8.5% of the genome); of these, 138 genes are poorly characterized. Regulation by ArcA in S. Typhimurium is similar, but distinct from that in E. coli. Thus, genes/operons involved in core metabolic pathways (e.g., succinyl-CoA, fatty acid degradation, cytochrome oxidase complexes, flagellar biosynthesis, motility, and chemotaxis) were regulated similarly in the two organisms. However, genes/operons present in both organisms, but regulated differently by ArcA in S. Typhimurium included those coding for ethanolamine utilization, lactate transport and metabolism, and succinate dehydrogenases. Salmonella-specific genes/operons regulated by ArcA included those required for propanediol utilization, flagellar genes (mcpAC, cheV), Gifsy-1 prophage genes, and three SPI-3 genes (mgtBC, slsA, STM3784). In agreement with our microarray data, the arcA mutant was non-motile, lacked flagella, and was as virulent in mice as the WT. Additionally, we identified a set of 120 genes whose regulation was shared with the anaerobic redox regulator, Fnr. Conclusion(s) We have identified the ArcA regulon in anaerobically grown S. Typhimurium. Our results demonstrated that in S. Typhimurium, ArcA serves as a transcriptional regulator coordinating cellular metabolism, flagella biosynthesis, and

  20. Integrative Analysis of Salmonellosis Outbreaks in Israel 1999-2012 Revealed an Invasive S. enterica Serovar 9,12:l,v:- and Endemic S. Typhimurium DT104 strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is the leading etiologic agent of bacterial foodborne outbreaks worldwide. Methods. Laboratory-based statistical surveillance, molecular and genomics analyses were applied to characterize Salmonella outbreaks pattern in Israel. 65,087 Salmonella isolates reported to the National ...

  1. Osteomyelitis caused by Salmonella enterica serovar derby in boa constrictor.

    PubMed

    de Souza, Suyene O; Casagrande, Renata A; Guerra, Priscila R; Cruz, Cláudio E F; Veit, Evandro; Cardoso, Marisa R I; Driemeier, David

    2014-09-01

    After demonstrating chronic weight loss, prostration, and muscle flaccidness, a captive-bred 9-mo-old boa constrictor (Boa constrictor constrictor) died and was submitted for necropsy. Along the spinal column there were multiple, yellowish white, macroscopic nodules of 1-5 mm in diameter in the ventral side of the vertebral body and in the intervertebral spaces. Severe multifocal necrotizing osteomyelitis associated with granulomatous inflammation was the main histologic finding in the vertebral column. In the liver, there was discrete but similar granulomatous changes. Positive anti-Salmonella immunostaining was observed in the spinal column and in the liver. Salmonella enterica serovar Derby was isolated from fragments of the spinal column. These bacteria are important cause of disease in captive reptiles. PMID:25314834

  2. Differences in attachment of Salmonella enterica serovars to cabbage and lettuce leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the ability of five Salmonella enterica serovars to attach to and colonize intact and cut lettuce (Iceberg, Romaine) and cabbage surfaces. Biofilm assay and attachment of Salmonella serovars to intact and cut leaves were determined. Bacterial populations of loosely and strong...

  3. The genome sequence of Salmonella enterica serovar Choleraesuis, a highly invasive and resistant zoonotic pathogen

    PubMed Central

    Chiu, Cheng-Hsun; Tang, Petrus; Chu, Chishih; Hu, Songnian; Bao, Qiyu; Yu, Jun; Chou, Yun-Ying; Wang, Hsin-Shih; Lee, Ying-Shiung

    2005-01-01

    Salmonella enterica serovar Choleraesuis (S.Choleraesuis), a highly invasive serovar among non-typhoidal Salmonella, usually causes sepsis or extra-intestinal focal infections in humans. S.Choleraesuis infections have now become particularly difficult to treat because of the emergence of resistance to multiple antimicrobial agents. The 4.7 Mb genome sequence of a multidrug-resistant S.Choleraesuis strain SC-B67 was determined. Genome wide comparison of three sequenced Salmonella genomes revealed that more deletion events occurred in S.Choleraesuis SC-B67 and S.Typhi CT18 relative to S.Typhimurium LT2. S.Choleraesuis has 151 pseudogenes, which, among the three Salmonella genomes, include the highest percentage of pseudogenes arising from the genes involved in bacterial chemotaxis signal-transduction pathways. Mutations in these genes may increase smooth swimming of the bacteria, potentially allowing more effective interactions with and invasion of host cells to occur. A key regulatory gene of TetR/AcrR family, acrR, was inactivated through the introduction of an internal stop codon resulting in overexpression of AcrAB that appears to be associated with ciprofloxacin resistance. While lateral gene transfer providing basic functions to allow niche expansion in the host and environment is maintained during the evolution of different serovars of Salmonella, genes providing little overall selective benefit may be lost rapidly. Our findings suggest that the formation of pseudogenes may provide a simple evolutionary pathway that complements gene acquisition to enhance virulence and antimicrobial resistance in S.Choleraesuis. PMID:15781495

  4. A novel phage element of Salmonella enterica serovar Enteritidis P125109 contributes to accelerated type III secretion system 2-dependent early inflammation kinetics in a mouse colitis model.

    PubMed

    Vishwakarma, Vikalp; Periaswamy, Balamurugan; Bhusan Pati, Niladri; Slack, Emma; Hardt, Wolf-Dietrich; Suar, Mrutyunjay

    2012-09-01

    Salmonella enterica subsp. I serovar Enteritidis exhibits type III secretion system 2 (TTSS2)-dependent early colonization and inflammation kinetics faster than those of closely related S. enterica serovar Typhimurium. To investigate the accelerated TTSS-2-dependent pathogenic potential of S. Enteritidis, we focused on its genome. Results of a previously published comparative genomic study revealed the presence of mutually exclusive genes in both serovars. In this study, we investigated the roles of six S. Enteritidis-specific genes in vivo by using differential fluorescence induction (DFI) through putative gene-specific promoters. The promoter construct associated with the gene locus SEN1140 induced green fluorescent protein (GFP) expression in the gut lumen, lamina propria, mesenteric lymph nodes, and related systemic organs. To further investigate the potential role of SEN1140, we compared a SEN1140 deletion mutant with S. Typhimurium in a TTSS1-deficient background. Interestingly, the S. Enteritidis mutant lacking SEN1140 did not show the unique TTSS-2-dependent early colonization and inflammation kinetic phenotype of S. Typhimurium. Consistent with this result, complementation of SEN1140 restored the TTSS-2-dependent accelerated inflammatory potential of S. Enteritidis. This report presents a suitable screening strategy that uses a combination of DFI, fluorescence-activated cell sorting, quantitative PCR, and wild-type isogenic tagged-strain techniques to explore the unique roles of S. Enteritidis-specific genes in bacterial pathogenesis. PMID:22753379

  5. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Napoli Strain SN310, Cause of a Multischool Outbreak in Milan, Italy, in 2014.

    PubMed

    Huedo, Pol; Gori, Maria; Scaltriti, Erika; Morganti, Marina; Casadei, Gabriele; Amato, Ettore; Pontello, Mirella

    2015-01-01

    We report the draft genome sequence of Salmonella enterica subsp. enterica serovar Napoli strain SN310, isolated from a stool sample of an affected pupil during a multischool outbreak in 2014 in Milan, Italy. This represents the first reported draft genome sequence of the emerging serovar Napoli. PMID:26358605

  6. Evaluation and comparison of molecular techniques for epidemiological typing of Salmonella enterica subsp. enterica serovar dublin.

    PubMed Central

    Liebisch, B; Schwarz, S

    1996-01-01

    A total of 28 unrelated isolates of the Salmonella enterica subsp. enterica serovar dublin (S. dublin) collected during a 6-year period, as well as four samples of the S. dublin live vaccine strain Bovisaloral and its prototype strain S. dublin 442/039, were investigated by different molecular typing methods for the following reasons: (i) to find the most discriminatory method for the epidemiological typing of isolates belonging to this Salmonella serovar and (ii) to evaluate these methods for their capacity to discriminate among the live vaccine strain Bovisaloral, its prototype strain S. dublin 442/039, and field isolates of the serovar dublin. Five different plasmid profiles were observed; a virulence plasmid of 76 kbp as identified by hybridization with an spvB-spvC gene probe was present in all isolates. The detection of 16S rRNA genes and that of IS200 elements proved to be unsuitable for the epidemiological typing of S. dublin; only one hybridization pattern could be observed with each of these methods. The results obtained from macrorestriction analysis strongly depended on the choice of restriction enzyme. While the enzyme NotI yielded the lowest discriminatory index among all enzymes tested, it was the only enzyme that allowed discrimination between the Bovisaloral vaccine strain and its prototype strain. In contrast to the enzymes XbaI and SpeI, which only differentiated among the S. dublin field isolates, XhoI as well as AvrII also produced restriction fragment patterns of the Bovisaloral strain and of its prototype strain that were not shared by any of the S. dublin field isolates. Macrorestriction analysis proved to be the most discriminatory method not only for the epidemiological typing of S. dublin field isolates but also for the identification of the S. dublin live vaccine strain Bovisaloral. PMID:8904430

  7. CTX-M-27 Producing Salmonella enterica Serotypes Typhimurium and Indiana Are Prevalent among Food-Producing Animals in China

    PubMed Central

    Zhang, Wen-Hui; Lin, Xiang-Yan; Xu, Liang; Gu, Xi-Xi; Yang, Ling; Li, Wan; Ren, Si-Qi; Liu, Ya-Hong; Zeng, Zhen-Ling; Jiang, Hong-Xia

    2016-01-01

    Salmonella spp. is one of the most important food-borne pathogens causing digestive tract and invasive infections in both humans and animals. Extended-spectrum β-lactamases (ESBLs) especially the CTX-M-type ESBLs are increasingly being reported worldwide and in China. These studies seldom focused on Salmonella isolates from food-producing animals. The aim of this study was to characterize the antimicrobial resistance profiles, serotypes and ESBLs and in particular, CTX-M producing Salmonella isolates from chickens and pigs in China. Salmonella isolates were identified by API20E system and polymerase chain reaction (PCR) assay; serotypes were determined using slide agglutination with hyperimmune sera; antimicrobial susceptibility was tested using the ager dilution method; the prevalence of ESBLs and PMQR genes were screened by PCR; CTX-M-producing isolates were further characterized by conjugation along with genetic relatedness and plasmid replicon type. In total, 159 Salmonella strains were identified, among which 95 strains were Salmonella enterica serovar Typhimurium, 63 strains were S. enterica serovar Indiana, and 1 strain was S. enterica serovar Enteritidis. All of these isolates presented multi-drug resistant phenotypes. Forty-five isolates carried blaCTX-M genes, the most common subtype was CTX-M-27(34), followed by CTX-M-65(7) and CTX-M-14(4). Most blaCTX-M genes were transmitted by non-typeable or IncN/IncFIB/IncP/IncA/C/IncHI2 plasmids with sizes ranging from 80 to 280 kb. In particular, all the 14 non-typeable plasmids were carrying blaCTX-M-27 gene and had a similar size. PFGE profiles indicated that CTX-M-positive isolates were clonally related among the same serotype, whilst the isolates of different serotypes were genetically divergent. This suggested that both clonal spread of resistant strains and horizontal transmission of the resistance plasmids contributed to the dissemination of blaCTX-M-9G-positive Salmonella isolates. The presence and spread

  8. CTX-M-27 Producing Salmonella enterica Serotypes Typhimurium and Indiana Are Prevalent among Food-Producing Animals in China.

    PubMed

    Zhang, Wen-Hui; Lin, Xiang-Yan; Xu, Liang; Gu, Xi-Xi; Yang, Ling; Li, Wan; Ren, Si-Qi; Liu, Ya-Hong; Zeng, Zhen-Ling; Jiang, Hong-Xia

    2016-01-01

    Salmonella spp. is one of the most important food-borne pathogens causing digestive tract and invasive infections in both humans and animals. Extended-spectrum β-lactamases (ESBLs) especially the CTX-M-type ESBLs are increasingly being reported worldwide and in China. These studies seldom focused on Salmonella isolates from food-producing animals. The aim of this study was to characterize the antimicrobial resistance profiles, serotypes and ESBLs and in particular, CTX-M producing Salmonella isolates from chickens and pigs in China. Salmonella isolates were identified by API20E system and polymerase chain reaction (PCR) assay; serotypes were determined using slide agglutination with hyperimmune sera; antimicrobial susceptibility was tested using the ager dilution method; the prevalence of ESBLs and PMQR genes were screened by PCR; CTX-M-producing isolates were further characterized by conjugation along with genetic relatedness and plasmid replicon type. In total, 159 Salmonella strains were identified, among which 95 strains were Salmonella enterica serovar Typhimurium, 63 strains were S. enterica serovar Indiana, and 1 strain was S. enterica serovar Enteritidis. All of these isolates presented multi-drug resistant phenotypes. Forty-five isolates carried bla CTX-M genes, the most common subtype was CTX-M-27(34), followed by CTX-M-65(7) and CTX-M-14(4). Most bla CTX-M genes were transmitted by non-typeable or IncN/IncFIB/IncP/IncA/C/IncHI2 plasmids with sizes ranging from 80 to 280 kb. In particular, all the 14 non-typeable plasmids were carrying bla CTX-M-27 gene and had a similar size. PFGE profiles indicated that CTX-M-positive isolates were clonally related among the same serotype, whilst the isolates of different serotypes were genetically divergent. This suggested that both clonal spread of resistant strains and horizontal transmission of the resistance plasmids contributed to the dissemination of bla CTX-M-9G-positive Salmonella isolates. The presence and

  9. Salmonella enterica serovar Kentucky isolates from dairy cows and poultry demonstrate different evolutionary histories and host-specific polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Kentucky is commonly isolated from dairy cows and poultry in the United States. Although it is not among the most frequently isolated serovars from cases of human salmonellosis, its high prevalence in livestock and poultry indicate it is a potential public...

  10. First report of iliacus abscess caused by Salmonella enterica serovar Othmarschen.

    PubMed

    Jha, Babita; Kim, Choon-Mee; Kim, Dong-Min; Chung, Jong-Hoon; Yoon, Na-Ra; Jha, Piyush; Kim, Seok Won; Jang, Sook Jin; Kim, Seon Gyeong; Chung, Jae Keun

    2016-02-01

    The non-typhoidal bacterium Salmonella enterica subspecies enterica serovar Othmarschen (Salmonella Othmarschen) is a rare human pathogen. Abscess formation due to non-typhoidal Salmonella infections is a very rare complication in this antibiotic era. We report the first case of iliacus abscess after a short period of gastroenteritis which was caused by non-typhoidal Salmonella enterica belonging to group C1, serovar Othmarschen in a patient without any underlying conditions. A young female presented in our hospital complaining of pain in right hip joint area. She gave a history of watery diarrhea 3 days before the onset of pain. On examination the patient was ill-looking and there was tenderness in the right hip joint area. S. enterica was identified using 16S rRNA gene amplification by PCR and serotyped to be serovar Othmarschen from the pus sample of iliacus abscess. This is the first reported case of iliacus abscess due to Salmonella serover Othmarschen infection. Our case suggests that S. enterica serovar Othmarschen can cause severe focal infections associated with gastroenteritis. The literature on the rare association of Salmonella enterica and abscess formation is reviewed. PMID:26482919

  11. Genes ycfR, sirA and yigG Contribute to the Surface Attachment of Salmonella enterica Typhimurium and Saintpaul to Fresh Produce

    PubMed Central

    Salazar, Joelle K.; Deng, Kaiping; Tortorello, Mary Lou; Brandl, Maria T.; Wang, Hui; Zhang, Wei

    2013-01-01

    Salmonella enterica is a frequent contaminant of minimally-processed fresh produce linked to major foodborne disease outbreaks. The molecular mechanisms underlying the association of this enteric pathogen with fresh produce remain largely unexplored. In our recent study, we showed that the expression of a putative stress regulatory gene, ycfR, was significantly induced in S. enterica upon exposure to chlorine treatment, a common industrial practice for washing and decontaminating fresh produce during minimal processing. Two additional genes, sirA involved in S. enterica biofilm formation and yigG of unknown function, were also found to be differentially regulated under chlorine stress. To further characterize the roles of ycfR, sirA, and yigG in S. enterica attachment and survival on fresh produce, we constructed in-frame deletions of all three genes in two different S. enterica serovars, Typhimurium and Saintpaul, which have been implicated in previous disease outbreaks linked to fresh produce. Bacterial attachment to glass and polystyrene microtiter plates, cell aggregation and hydrophobicity, chlorine resistance, and surface attachment to intact spinach leaf and grape tomato were compared among wild-type strains, single-gene deletion mutants, and their respective complementation mutants. The results showed that deletions of ycfR, sirA, and yigG reduced bacterial attachment to glass and polystyrene as well as fresh produce surface with or without chlorine treatment in both Typhimurium and Saintpaul. Deletion of ycfR in Typhimurium significantly reduced bacterial chlorine resistance and the attachment to the plant surfaces after chlorinated water washes. Deletions of ycfR in Typhimurium and yigG in Saintpaul resulted in significant increase in cell aggregation. Our findings suggest that ycfR, sirA, and yigG collectively contribute to S. enterica surface attachment and survival during post-harvest minimal processing of fresh produce. PMID:23451197

  12. Genes ycfR, sirA and yigG contribute to the surface attachment of Salmonella enterica Typhimurium and Saintpaul to fresh produce.

    PubMed

    Salazar, Joelle K; Deng, Kaiping; Tortorello, Mary Lou; Brandl, Maria T; Wang, Hui; Zhang, Wei

    2013-01-01

    Salmonella enterica is a frequent contaminant of minimally-processed fresh produce linked to major foodborne disease outbreaks. The molecular mechanisms underlying the association of this enteric pathogen with fresh produce remain largely unexplored. In our recent study, we showed that the expression of a putative stress regulatory gene, ycfR, was significantly induced in S. enterica upon exposure to chlorine treatment, a common industrial practice for washing and decontaminating fresh produce during minimal processing. Two additional genes, sirA involved in S. enterica biofilm formation and yigG of unknown function, were also found to be differentially regulated under chlorine stress. To further characterize the roles of ycfR, sirA, and yigG in S. enterica attachment and survival on fresh produce, we constructed in-frame deletions of all three genes in two different S. enterica serovars, Typhimurium and Saintpaul, which have been implicated in previous disease outbreaks linked to fresh produce. Bacterial attachment to glass and polystyrene microtiter plates, cell aggregation and hydrophobicity, chlorine resistance, and surface attachment to intact spinach leaf and grape tomato were compared among wild-type strains, single-gene deletion mutants, and their respective complementation mutants. The results showed that deletions of ycfR, sirA, and yigG reduced bacterial attachment to glass and polystyrene as well as fresh produce surface with or without chlorine treatment in both Typhimurium and Saintpaul. Deletion of ycfR in Typhimurium significantly reduced bacterial chlorine resistance and the attachment to the plant surfaces after chlorinated water washes. Deletions of ycfR in Typhimurium and yigG in Saintpaul resulted in significant increase in cell aggregation. Our findings suggest that ycfR, sirA, and yigG collectively contribute to S. enterica surface attachment and survival during post-harvest minimal processing of fresh produce. PMID:23451197

  13. Multiple antimicrobial resistant Salmonella enterica serovar Paratyphi B variant Java in cattle: a case report.

    PubMed

    Evans, S J; Davies, R H; Binns, S H; Liebana, E; Jones, T W H; Millar, M F; Threlfall, E J; Ward, L R; Hopkins, K L; Mackay, P H S; Gayford, P J R

    2005-03-12

    An epidemiological investigation of a calf rearing premises and a closely associated dairy herd was carried out after the isolation of Salmonella enterica serovar Paratyphi B variant Java phage type 3b variant 2 from clinically diseased calves on the premises. The isolate was resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, tetracyclines, trimethoprim and cefoperazone. The organism was widespread on the calf unit and was also recovered from the dairy premises, mainly from groups of weaned calves. The investigation was extended to 10 epidemiologically linked farms but no S Java was isolated from any of the 40 to 60 samples collected from each premises. Molecular studies showed that the S Java isolates were genetically most similar to isolates from cases of human disease associated with ornamental fish tanks or feed. Long PCR and resistance gene profiling identified a resistance island which was indistinguishable from the human 'fish tank' strain of S Java and animal and human epidemic strains of S Typhimurium DT104. The isolates were clearly distinguished from multi-resistant S Java strains commonly associated with continental poultry. This is the first report of S Java with this resistance pattern in Great Britain. PMID:15789647

  14. Evaluation of regulated delayed attenuation strategies for Salmonella enterica serovar Typhi vaccine vectors in neonatal and infant mice.

    PubMed

    Shi, Huoying; Wang, Shifeng; Curtiss, Roy

    2013-06-01

    We developed regulated delayed attenuation strategies for Salmonella vaccine vectors. In this study, we evaluated the combination of these strategies in recombinant attenuated Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium vaccine vectors with similar genetic backgrounds in vitro and in vivo. Our goal is to develop a vaccine to prevent Streptococcus pneumoniae infection in newborns; thus, all strains delivered a pneumococcal antigen PspA and the impact of maternal antibodies was evaluated. The results showed that all strains with the regulated delayed attenuated phenotype (RDAP) displayed an invasive ability stronger than that of the S. Typhi vaccine strain, Ty21a, but weaker than that of their corresponding wild-type parental strains. The survival curves of different RDAP vaccine vectors in vitro and in vivo exhibited diverse regulated delayed attenuation kinetics, which was different from S. Typhi Ty21a and the wild-type parental strains. Under the influence of maternal antibody, the persistence of the S. Typhimurium RDAP strain displayed a regulated delayed attenuation trend in nasal lymphoid tissue (NALT), lung, and Peyer's patches, while the persistence of S. Typhi RDAP strains followed the curve only in NALT. The bacterial loads of S. Typhi RDAP strains were lower in NALT, lung, and Peyer's patches in mice born to immune mothers than in those born to naive mothers. In accordance with these results, RDAP vaccine strains induced high titers of IgG antibodies against PspA and against Salmonella lipopolysaccharides. Immunization of mothers with S. Typhi RDAP strains enhanced the level of vaginal mucosal IgA, gamma interferon (IFN-γ), and interleukin 4 (IL-4) and resulted in a higher level of protection against S. pneumoniae challenge. PMID:23616408

  15. Transposon Mutagenesis of Salmonella enterica Serovar Enteritidis Identifies Genes That Contribute to Invasiveness in Human and Chicken Cells and Survival in Egg Albumen

    PubMed Central

    Zhou, Xiaohui; Kim, Hye-Young; Call, Douglas R.; Guard, Jean

    2012-01-01

    Salmonella enterica serovar Enteritidis is an important food-borne pathogen, and chickens are a primary reservoir of human infection. While most knowledge about Salmonella pathogenesis is based on research conducted on Salmonella enterica serovar Typhimurium, S. Enteritidis is known to have pathobiology specific to chickens that impacts epidemiology in humans. Therefore, more information is needed about S. Enteritidis pathobiology in comparison to that of S. Typhimurium. We used transposon mutagenesis to identify S. Enteritidis virulence genes by assay of invasiveness in human intestinal epithelial (Caco-2) cells and chicken liver (LMH) cells and survival within chicken (HD-11) macrophages as a surrogate marker for virulence. A total of 4,330 transposon insertion mutants of an invasive G1 Nalr strain were screened using Caco-2 cells. This led to the identification of attenuating mutations in a total of 33 different loci, many of which include genes previously known to contribute to enteric infection (e.g., Salmonella pathogenicity island 1 [SPI-1], SPI-4, SPI-5, CS54, fliH, fljB, csgB, spvR, and rfbMN) in S. Enteritidis and other Salmonella serovars. Several genes or genomic islands that have not been reported previously (e.g., SPI-14, ksgA, SEN0034, SEN2278, and SEN3503) or that are absent in S. Typhimurium or in most other Salmonella serovars (e.g., pegD, SEN1152, SEN1393, and SEN1966) were also identified. Most mutants with reduced Caco-2 cell invasiveness also showed significantly reduced invasiveness in chicken liver cells and impaired survival in chicken macrophages and in egg albumen. Consequently, these genes may play an important role during infection of the chicken host and also contribute to successful egg contamination by S. Enteritidis. PMID:22988017

  16. Reduced transaminase B (IlvE) activity caused by the lack of yjgF is dependent on the status of threonine deaminase (IlvA) in Salmonella enterica serovar Typhimurium.

    PubMed

    Schmitz, George; Downs, Diana M

    2004-02-01

    The YjgF/YER057c/UK114 family is a highly conserved class of proteins that is represented in the three domains of life. Thus far, a biochemical function demonstrated for these proteins in vivo or in vitro has yet to be defined. In several organisms, strains lacking a YjgF homolog have a defect in branched-chain amino acid biosynthesis. This study probes the connection between yjgF and isoleucine biosynthesis in Salmonella enterica. In strains lacking yjgF the specific activity of transaminase B, catalyzing the last step in the synthesis of isoleucine, was reduced. In the absence of yjgF, transaminase B activity could be restored by inhibiting threonine deaminase, the first enzymatic step in isoleucine biosynthesis. Strains lacking yjgF showed an increased sensitivity to sulfometruron methyl, a potent inhibitor of acetolactate synthase. Based on work described here and structural reports in the literature, we suggest a working model in which YjgF has a role in protecting the cell from toxic effects of imbalanced ketoacid pools. PMID:14729707

  17. Specific Monoclonal Antibody Overcomes the Salmonella enterica Serovar Typhimurium’s Adaptive Mechanisms of Intramacrophage Survival and Replication

    PubMed Central

    Aribam, Swarmistha Devi; Harada, Tomoyuki; Elsheimer-Matulova, Marta; Iwata, Taketoshi; Kanehira, Katsushi; Hikono, Hirokazu; Matsui, Hidenori; Ogawa, Yohsuke; Shimoji, Yoshihiro; Eguchi, Masahiro

    2016-01-01

    Salmonella-specific antibodies play an important role in host immunity; however, the mechanisms of Salmonella clearance by pathogen-specific antibodies remain to be completely elucidated since previous studies on antibody-mediated protection have yielded inconsistent results. These inconsistencies are at least partially attributable to the use of polyclonal antibodies against Salmonella antigens. Here, we developed a new monoclonal antibody (mAb)-449 and identified its related immunogen that protected BALB/c mice from infection with Salmonella enterica serovar Typhimurium. In addition, these data indicate that the mAb-449 immunogen is likely a major protective antigen. Using in vitro infection studies, we also analyzed the mechanism by which mAb-449 conferred host protection. Notably, macrophages infected with mAb-449-treated S. Typhimurium showed enhanced pathogen uptake compared to counterparts infected with control IgG-treated bacteria. Moreover, these macrophages produced elevated levels of pro-inflammatory cytokine TNFα and nitric oxide, indicating that mAb-449 enhanced macrophage activation. Finally, the number of intracellular bacteria in mAb-449-activated macrophages decreased considerably, while the opposite was found in IgG-treated controls. Based on these findings, we suggest that, although S. Typhimurium has the potential to survive and replicate within macrophages, host production of a specific antibody can effectively mediate macrophage activation for clearance of intracellular bacteria. PMID:26986057

  18. Escherichia coli O157:H7 Induces Stronger Plant Immunity than Salmonella enterica Typhimurium SL1344

    PubMed Central

    Roy, Debanjana; Panchal, Shweta; Rosa, Bruce A

    2014-01-01

    Consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. In this study, we assessed plant defense responses induced by the fully pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium SL1344 in both Arabidopsis thaliana and lettuce (Lactuca sativa). Unlike SL1344, O157:H7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. For instance, O157:H7 triggered stomatal closure even under high relative humidity (RH); an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 as compared to SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis resulting in low bacterial titers in the plant apoplast suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies. PMID:23301812

  19. Variable Carbon Catabolism among Salmonella enterica Serovar Typhi Isolates

    PubMed Central

    Chai, Lay Ching; Kong, Boon Hong; Elemfareji, Omar Ismail; Thong, Kwai Lin

    2012-01-01

    Background Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. Methodology/Principal Findings To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas oftyphoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates) was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. Conclusion The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen. PMID:22662115

  20. SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION MODULATES DIVERSE FUNCTIONAL PROCESSES OF CHICKEN MACROPHAGE AT THE TRANSCRIPTIONAL LEVEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) is a major etiologic agent of non-typhoid salmonellosis. The organisms colonize adult chicken hosts without causing overt clinical signs. The immunological mechanisms underlying the silent and persistent infection of chickens by SE are not clearly underst...

  1. Extremely Drug-Resistant Salmonella enterica Serovar Senftenberg Infections in Patients in Zambia

    PubMed Central

    Joensen, Katrine Grimstrup; Lukwesa-Musyani, Chileshe; Kalondaa, Annie; Leekitcharoenphon, Pimlapas; Nakazwe, Ruth; Aarestrup, Frank M.; Hasman, Henrik; Mwansa, James C. L.

    2013-01-01

    Two cases of extremely drug-resistant Salmonella enterica serovar Senftenberg isolated from patients in Zambia were investigated by utilizing MIC determinations and whole-genome sequencing. The isolates were resistant to, and harbored genes toward, nine drug classes, including fluoroquinolones and extended-spectrum cephalosporins, contained two plasmid replicons, and differed by 93 single-nucleotide polymorphisms. PMID:23077128

  2. Potential International Spread of Multidrug-Resistant Invasive Salmonella enterica Serovar Enteritidis

    PubMed Central

    Rodicio, M. Rosario; Guerra, Beatriz; Hopkins, Katie L.

    2012-01-01

    In developing countries, Salmonella enterica serovar Enteritidis causes substantial illness and death, and drug resistance is increasing. Isolates from the United Kingdom containing virulence-resistance plasmids were characterized. They mainly caused invasive infections in adults linked to Africa. The common features in isolates from these continents indicate the role of human travel in their spread. PMID:22709653

  3. Transcriptional Response of Chicken Macrophages to Salmonella enterica serovar Enteritidis Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) continues to be the predominant etiologic agent of salmonellosis, with contaminated egg products being the primary source of infection. At the present time, the molecular and immunological mechanisms involved in SE colonization of chicken hosts are not we...

  4. TRANSCRIPTIONAL RESPONSE OF CHICKEN MACROPHAGES TO SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transcriptional profiles of chicken macrophages (HD11) infected with Salmonella enterica serovar Enteritidis (SE) were analyzed by using avian macrophage microarray and real time RT-PCR. Out of 4,906 array elements interrogated, 269 genes exhibited a 2-fold change (P < 0.001) over a 24-hour time...

  5. Genome Sequence of Salmonella enterica Serovar Typhi Oral Vaccine Strain Ty21a.

    PubMed

    Xu, Deqi; Cisar, John O; Poly, Frédéric; Yang, Jinghua; Albanese, Jason; Dharmasena, Madushini; Wai, Tint; Guerry, Patricia; Kopecko, Dennis J

    2013-01-01

    Attenuated Salmonella enterica serovar Typhi strain Ty21a is an important vaccine for controlling typhoid fever and serves as an oral vector for delivering heterologous antigens. The key attenuating features of this randomly mutated strain remain in question. Genome sequencing has revealed 679 single nucleotide polymorphisms (SNPs), and will help define alterations contributing to Ty21a safety and immunogenicity. PMID:23969054

  6. Complete Genome Sequence of Salmonella enterica Serovar Agona Pulsed-Field Type SAGOXB.0066, Cause of a 2008 Pan-European Outbreak.

    PubMed

    McCusker, Matthew P; Hokamp, Karsten; Buckley, James F; Wall, Patrick G; Martins, Marta; Fanning, Séamus

    2014-01-01

    Salmonella enterica serovar Agona is in the top 10 most common nontyphoidal serovars reported in humans in the European Union. Here we report the complete genome sequence of an S. enterica serovar Agona isolate, designated 24249, that was the cause of a pan-European outbreak in 2008 with 163 confirmed cases reported. PMID:24459278

  7. Rapid multiplex PCR and Real-Time TaqMan PCR assays for detection of Salmonella enterica and the highly virulent serovars Choleraesuis and Paratyphi C

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is a human pathogen with over 2,500 serovars characterized. S. enterica serovars Choleraesuis (Cs) and Paratyphi C (Pc) are two globally distributed serovars. We have developed a rapid molecular typing method to detect Cs and Pc in food samples by using a comparative genomics ap...

  8. Repeated isolation of Salmonella enterica Goverdhan, a very rare serovar, from Danish poultry surveillance samples.

    PubMed

    Pedersen, Karl; Sørensen, Gitte; Szabo, Istvan; Hächler, Herbert; Le Hello, Simon

    2014-12-01

    We report here the appearance of a very rare serovar of Salmonella, S. enterica subsp. enterica serovar Goverdhan, in routine Salmonella surveillance samples from Danish poultry production. S. Goverdhan was found on nine occasions: in one broiler breeder farm in October 2010, four broiler farms and one broiler breeder farm in June-September 2012, two broiler breeder flocks simultaneously in June 2013, and one layer flock in July 2013. The five isolates from 2012 and the three isolates from 2013 had identical pulsed-field gel electrophoresis profiles, whereas the profile of the isolate from 2010 deviated in a single band. It is the first time this serovar has been described in samples from poultry. The origin of the bacterium is still unknown, but it is suggested that it may have been a pseudo-outbreak caused by contaminated sampling material. PMID:25448451

  9. Molecular identification of Salmonella enterica subsp. enterica serovar Gallinarum biovars Gallinarum and Pullorum by a duplex PCR assay.

    PubMed

    Batista, Diego Felipe Alves; de Freitas Neto, Oliveiro Caetano; de Almeida, Adriana Maria; Barrow, Paul Andrew; de Oliveira Barbosa, Fernanda; Berchieri Junior, Angelo

    2016-07-01

    Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (S Gallinarum) and biovar Pullorum (S Pullorum) are 2 poultry pathogens that cause major economic losses to the poultry industry worldwide. Control of both diseases mainly relies on the adoption of biosecurity programs, and success is dependent on accurate and fast detection. Based on this concept, we developed a duplex PCR assay, targeting 2 chromosomal sequences, which allowed us to precisely identify and differentiate S Gallinarum and S Pullorum field strains. This assay was validated by testing genomic DNA from 40 S Gallinarum and 29 S Pullorum field strains, 87 other Salmonella serovars, and 7 non-Salmonella strains. The serovar identifier region (SIR) primers produced a fragment only in S Gallinarum and S Pullorum strains, whereas the fragment from the ratA coding sequence, which was previously demonstrated to differentiate the 2 biovars, was also amplified from other Salmonella serovars. Our results showed that the combination of both SIR and ratA amplifications could be used to identify as well as to differentiate colonies of S Gallinarum and S Pullorum reliably. Thus, we believe this methodology can be a useful ancillary tool for routine veterinary diagnostic laboratories by providing rapid, accurate results. PMID:27216724

  10. Draft Genome Sequence of a Salmonella enterica subsp. enterica Serovar Gallinarum bv. Gallinarum Isolate Associated with Fowl Typhoid Outbreaks in Brazil

    PubMed Central

    De Carli, Silvia; Gräf, Tiago; Mayer, Fabiana Q.; Cibulski, Samuel; Lehmann, Fernanda K. M.; Fonseca, André S. K.; Ikuta, Nilo

    2016-01-01

    Salmonella enterica subsp. enterica serovar Gallinarum bv. Gallinarum strains are bird pathogens causing fowl typhoid (FT). Isolate BR_RS12 was obtained from a poultry flock with FT in 2014. The sequencing of this genome will enable to track the origin of the recent outbreaks in Brazil. PMID:26950322

  11. Draft Genome Sequence and Annotation of Phyllosphere-Persisting Salmonella enterica subsp. enterica Serovar Livingstone Strain CKY-S4, Isolated from an Urban Lake in Regina, Canada.

    PubMed

    Tambalo, Dinah D; Perry, Benjamin J; Fitzgerald, Stephen F; Cameron, Andrew D S; Yost, Christopher K

    2015-01-01

    Here, we report the first draft genome sequence of Salmonella enterica subsp. enterica serovar Livingstone. This S. Livingstone strain CKY-S4 displayed biofilm formation and cellulose production and could persist on lettuce. This genome may help the study of mechanisms by which enteric pathogens colonize food crops. PMID:26272568

  12. Draft Genome Sequence and Annotation of Phyllosphere-Persisting Salmonella enterica subsp. enterica Serovar Livingstone Strain CKY-S4, Isolated from an Urban Lake in Regina, Canada

    PubMed Central

    Tambalo, Dinah D.; Perry, Benjamin J.; Fitzgerald, Stephen F.; Cameron, Andrew D. S.

    2015-01-01

    Here, we report the first draft genome sequence of Salmonella enterica subsp. enterica serovar Livingstone. This S. Livingstone strain CKY-S4 displayed biofilm formation and cellulose production and could persist on lettuce. This genome may help the study of mechanisms by which enteric pathogens colonize food crops. PMID:26272568

  13. A Phylogenetic and Phenotypic Analysis of Salmonella enterica Serovar Weltevreden, an Emerging Agent of Diarrheal Disease in Tropical Regions.

    PubMed

    Makendi, Carine; Page, Andrew J; Wren, Brendan W; Le Thi Phuong, Tu; Clare, Simon; Hale, Christine; Goulding, David; Klemm, Elizabeth J; Pickard, Derek; Okoro, Chinyere; Hunt, Martin; Thompson, Corinne N; Phu Huong Lan, Nguyen; Tran Do Hoang, Nhu; Thwaites, Guy E; Le Hello, Simon; Brisabois, Anne; Weill, François-Xavier; Baker, Stephen; Dougan, Gordon

    2016-02-01

    Salmonella enterica serovar Weltevreden (S. Weltevreden) is an emerging cause of diarrheal and invasive disease in humans residing in tropical regions. Despite the regional and international emergence of this Salmonella serovar, relatively little is known about its genetic diversity, genomics or virulence potential in model systems. Here we used whole genome sequencing and bioinformatics analyses to define the phylogenetic structure of a diverse global selection of S. Weltevreden. Phylogenetic analysis of more than 100 isolates demonstrated that the population of S. Weltevreden can be segregated into two main phylogenetic clusters, one associated predominantly with continental Southeast Asia and the other more internationally dispersed. Subcluster analysis suggested the local evolution of S. Weltevreden within specific geographical regions. Four of the isolates were sequenced using long read sequencing to produce high quality reference genomes. Phenotypic analysis in Hep-2 cells and in a murine infection model indicated that S. Weltevreden were significantly attenuated in these models compared to the classical S. Typhimurium reference strain SL1344. Our work outlines novel insights into this important emerging pathogen and provides a baseline understanding for future research studies. PMID:26867150

  14. A Phylogenetic and Phenotypic Analysis of Salmonella enterica Serovar Weltevreden, an Emerging Agent of Diarrheal Disease in Tropical Regions

    PubMed Central

    Makendi, Carine; Page, Andrew J.; Wren, Brendan W.; Le Thi Phuong, Tu; Clare, Simon; Hale, Christine; Goulding, David; Klemm, Elizabeth J.; Pickard, Derek; Okoro, Chinyere; Hunt, Martin; Thompson, Corinne N.; Phu Huong Lan, Nguyen; Tran Do Hoang, Nhu; Thwaites, Guy E.; Le Hello, Simon; Brisabois, Anne; Weill, François-Xavier; Baker, Stephen; Dougan, Gordon

    2016-01-01

    Salmonella enterica serovar Weltevreden (S. Weltevreden) is an emerging cause of diarrheal and invasive disease in humans residing in tropical regions. Despite the regional and international emergence of this Salmonella serovar, relatively little is known about its genetic diversity, genomics or virulence potential in model systems. Here we used whole genome sequencing and bioinformatics analyses to define the phylogenetic structure of a diverse global selection of S. Weltevreden. Phylogenetic analysis of more than 100 isolates demonstrated that the population of S. Weltevreden can be segregated into two main phylogenetic clusters, one associated predominantly with continental Southeast Asia and the other more internationally dispersed. Subcluster analysis suggested the local evolution of S. Weltevreden within specific geographical regions. Four of the isolates were sequenced using long read sequencing to produce high quality reference genomes. Phenotypic analysis in Hep-2 cells and in a murine infection model indicated that S. Weltevreden were significantly attenuated in these models compared to the classical S. Typhimurium reference strain SL1344. Our work outlines novel insights into this important emerging pathogen and provides a baseline understanding for future research studies. PMID:26867150

  15. Identification of Salmonella enterica serovar Dublin-specific sequences by subtractive hybridization and analysis of their role in intestinal colonization and systemic translocation in cattle.

    PubMed

    Pullinger, Gillian D; Dziva, Francis; Charleston, Bryan; Wallis, Timothy S; Stevens, Mark P

    2008-11-01

    Salmonella enterica serovar Dublin is a host-restricted serovar associated with typhoidal disease in cattle. In contrast, the fowl-associated serovar S. enterica serovar Gallinarum is avirulent in calves, yet it invades ileal mucosa and induces enteritis at levels comparable to those induced by S. enterica serovar Dublin. Suppression subtractive hybridization was employed to identify S. enterica serovar Dublin strain SD3246 genes absent from S. enterica serovar Gallinarum strain SG9. Forty-one S. enterica serovar Dublin fragments were cloned and sequenced. Among these, 24 mobile-element-associated genes were identified, and 12 clones exhibited similarity with sequences of known or predicted function in other serovars. Three S. enterica serovar Dublin-specific regions were homologous to regions from the genome of Enterobacter sp. strain 638. Sequencing of fragments adjacent to these three sequences revealed the presence of a 21-kb genomic island, designated S. enterica serovar Dublin island 1 (SDI-1). PCR analysis and Southern blotting showed that SDI-1 is highly conserved within S. enterica serovar Dublin isolates but rarely found in other serovars. To probe the role of genes identified by subtractive hybridization in vivo, 24 signature-tagged S. enterica serovar Dublin SD3246 mutants lacking loci not present in Salmonella serovar Gallinarum SG9 were created and screened by oral challenge of cattle. Though attenuation of tagged SG9 and SD3246 Salmonella pathogenicity island-1 (SPI-1) and SPI-2 mutant strains was detected, no obvious defects of these 24 mutants were detected. Subsequently, a DeltaSDI-1 mutant was found to exhibit weak but significant attenuation compared with the parent strain in coinfection of calves. SDI-1 mutation did not impair invasion, intramacrophage survival, or virulence in mice, implying that SDI-1 does not influence fitness per se and may act in a host-specific manner. PMID:18794283

  16. Autoinducer-2 controls virulence of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial communication via quorum sensing (QS) has been reported to be important in the production of virulence factors, antibiotic sensitivity, and biofilm development. Three QS systems, known as the autoinducer (AI) - AI-1, AI-2, and AI-3 systems, have been identified previously in the foodborne ...

  17. Mitsuokella jalaludinii inhibits growth of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of Salmonella. Anaerobic culture supernatants of 973 bacterial isolates from the gastrointestinal tr...

  18. Mitsuokella jalaludinii inhibits growth of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of Salmonella. Anaerobic culture supernates of 973 bacterial isolates from the gastrointestinal trac...

  19. Salmonella enterica serovars Typhimurium and Typhi as model organisms

    PubMed Central

    Garai, Preeti; Gnanadhas, Divya Prakash; Chakravortty, Dipshikha

    2012-01-01

    The lifestyle of intracellular pathogens has always questioned the skill of a microbiologist in the context of finding the permanent cure to the diseases caused by them. The best tool utilized by these pathogens is their ability to reside inside the host cell, which enables them to easily bypass the humoral immunity of the host, such as the complement system. They further escape from the intracellular immunity, such as lysosome and inflammasome, mostly by forming a protective vacuole-bound niche derived from the host itself. Some of the most dreadful diseases are caused by these vacuolar pathogens, for example, tuberculosis by Mycobacterium or typhoid fever by Salmonella. To deal with such successful pathogens therapeutically, the knowledge of a host-pathogen interaction system becomes primarily essential, which further depends on the use of a model system. A well characterized pathogen, namely Salmonella, suits the role of a model for this purpose, which can infect a wide array of hosts causing a variety of diseases. This review focuses on various such aspects of research on Salmonella which are useful for studying the pathogenesis of other intracellular pathogens. PMID:22722237

  20. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum

    PubMed Central

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; Farris Hanna, Leigh; Schifferli, Dieter M.; Maloy, Stanley; Dinsdale, Elizabeth A.; Edwards, Robert A.

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars. PMID:26039056

  1. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum.

    PubMed

    Matthews, T David; Schmieder, Robert; Silva, Genivaldo G Z; Busch, Julia; Cassman, Noriko; Dutilh, Bas E; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J; Farris Hanna, Leigh; Schifferli, Dieter M; Maloy, Stanley; Dinsdale, Elizabeth A; Edwards, Robert A

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars. PMID:26039056

  2. Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars

    PubMed Central

    Di Cesare, Andrea; Losasso, Carmen; Barco, Lisa; Eckert, Ester M.; Conficoni, Daniele; Sarasini, Giulia; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs. PMID:27357537

  3. Genomic comparison of the closely-related Salmonella enterica serovars enteritidis, dublin and gallinarum

    DOE PAGESBeta

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; et al

    2015-06-03

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content betweenmore » strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.« less

  4. Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars.

    PubMed

    Di Cesare, Andrea; Losasso, Carmen; Barco, Lisa; Eckert, Ester M; Conficoni, Daniele; Sarasini, Giulia; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs. PMID:27357537

  5. Invasive Salmonella enterica serotype typhimurium infections, Democratic Republic of the Congo, 2007-2011.

    PubMed

    Ley, Benedikt; Le Hello, Simon; Lunguya, Octavie; Lejon, Veerle; Muyembe, Jean-Jacques; Weill, François-Xavier; Jacobs, Jan

    2014-04-01

    Infection with Salmonella enterica serotype Typhimurium sequence type (ST) 313 is associated with high rates of drug resistance, bloodstream infections, and death. To determine whether ST313 is dominant in the Democratic Republic of the Congo, we studied 180 isolates collected during 2007-2011; 96% belonged to CRISPOL type CT28, which is associated with ST313. PMID:24655438

  6. A community effort towards a knowledge-base and mathematical model of the human pathogen Salmonella Typhimurium LT2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic reconstructions (MRs) are common denominators in systems biology and represent biochemical, genetic, and genomic (BiGG) knowledge-bases for target organisms by capturing currently available information in a consistent, structured manner. Salmonella enterica subspecies I serovar Typhimurium...

  7. Complete Closed Genome Sequences of Salmonella enterica subsp. enterica Serotypes Anatum, Montevideo, Typhimurium, and Newport, Isolated from Beef, Cattle, and Humans.

    PubMed

    Harhay, Dayna M; Bono, James L; Smith, Timothy P L; Fields, Patricia I; Dinsmore, Blake A; Santovenia, Monica; Kelley, Christy M; Wang, Rong; Harhay, Gregory P

    2016-01-01

    Salmonella enterica spp. are a diverse group of bacteria with a wide range of virulence potential. To facilitate genome comparisons across this virulence spectrum, we present eight complete closed genome sequences of four S. enterica serotypes (Anatum, Montevideo, Typhimurium, and Newport), isolated from various cattle samples and from humans. PMID:26847891

  8. Complete closed genome sequences of Salmonella enterica subsp. enterica serotypes Anatum, Montevideo, Typhimurium and Newport, isolated from beef, cattle, and humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica are a versatile group of bacteria with a wide range in virulence potential. To facilitate genome comparisons across this virulence spectrum, we present eight complete closed genome sequences of four S. enterica serotypes (Anatum, Montevideo, Typhimurium, and Newport) isolated fro...

  9. Metabolic parameters linked by Phenotype MicroArray to acid resistance profiles of poultry-associated Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenotype microarrays were analyzed for 51 datasets derived from Salmonella enterica. The top 4 serovars associated with poultry products and one associated with turkey, respectively Typhimurium, Enteritidis, Heidelberg, Infantis and Senftenberg, were represented. Datasets were clustered into two ...

  10. Structures of the SEp22 dodecamer, a Dps-like protein from Salmonella enterica subsp. enterica serovar Enteritidis

    PubMed Central

    Miyamoto, Takanori; Asahina, Yasuko; Miyazaki, Shohei; Shimizu, Hidetoshi; Ohto, Umeharu; Noguchi, Shuji; Satow, Yoshinori

    2011-01-01

    The crystal structure of SEp22, a DNA-binding protein from starved cells from Salmonella enterica subsp. enterica serovar Enteritidis, has been determined in two forms: the native state at 1.25 Å resolution and an iron-soaked form at 1.30 Å resolution. The SEp22 protomers form a dodecameric shell with 23 symmetry and a single iron ion per protomer was found at the ferroxidase centre in the iron-soaked form. Along the threefold axes of the 23 symmetry, hydrophilic Asp channels that consist of Asp146 were found. Iron ions may flow into the cavity of the dodecameric shell through the Asp channels. PMID:21206015

  11. Intermediate Susceptibility to Ciprofloxacin among Salmonella enterica Serovar Typhi Isolates in Lima, Peru

    PubMed Central

    Lejon, Veerle; Horna, Gertrudis; Astocondor, Lizeth; Vanhoof, Raymond; Bertrand, Sophie; Jacobs, Jan

    2014-01-01

    Thirty-three Salmonella enterica serovar Typhi blood isolates from Lima, Peru (2008 to 2012), were fully susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, ceftriaxone, and tetracycline; 8/33 (24.2%) showed intermediate susceptibility to ciprofloxacin carrying mutations in the quinolone resistance-determining region of the gyrA gene (Ser83-Phe and Asp87-Asn) and in the gyrB gene (Ser464-Phe). PMID:24371234

  12. Cell yields and fermentation responses of a Salmonella Typhimurium poultry isolate at different dilution rates in an anaerobic steady state continuous culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of these studies were to determine cell yield and fermentation responses of a Salmonella enterica serovar Typhimurium poultry isolate using various dilution rates in steady state continuous culture incubations. S. enterica Typhimurium cells were propagated in continuous cultures with ...

  13. Salmonella Serovars from Foodborne and Waterborne Diseases in Korea, 1998-2007: Total Isolates Decreasing Versus Rare Serovars Emerging

    PubMed Central

    2010-01-01

    Salmonella enterica has been one of the most widespread foodborne pathogens in Korea. Between 1998 and 2007, a total of 9,472 Salmonella isolates were identified from foodborne and waterborne illness patients. During that time, Korea was transitioning into a developed country in industry as well as in its hygiene system. Although the isolation number of total Salmonella including serovar Typhi has decreased since 1999, the isolation of rare Salmonella serovars has emerged. Three most prevalent serovars during 1998-2007 were S. enterica Typhi, S. enterica Enteritidis, and S. enterica Typhimurium. There were remarkable outbreaks caused by rare serovars such as S. enterica Othmarschen, S. enterica London and S. enterica Paratyphi A, and overseas traveler-associated infections caused by S. enterica Weltevreden and S. enterica Anatum. Salmonella serovars from overseas travelers made a diverse Salmonella serovar pool in Korea. This study is the first review of the status of the human Salmonella infection trend in a developing country during 1998-2007. Newly emerging rare Salmonella serovars should be traced and investigated to control new type pathogens in the developed world. PMID:21165281

  14. Comparison of methods for quantitating Salmonella enterica Typhimurium and Heidelberg strain attachment to reusable plastic shipping container coupons and preliminary assessment of sanitizer efficacy.

    PubMed

    Shi, Zhaohao; Baker, Christopher A; Lee, Sang In; Park, Si Hong; Kim, Sun Ae; Ricke, Steven C

    2016-09-01

    Salmonella serovars, one of the leading contributors to foodborne illness and are especially problematic for foods that are not cooked before consumption, such as fresh produce. The shipping containers that are used to transport and store fresh produce may play a role in cross contamination and subsequent illnesses. However, methods for quantitatively attached cells are somewhat variable. The overall goal of this study was to compare conventional plating with molecular methods for quantitating attached representative strains for Salmonella Typhimurium and Heidelberg on reusable plastic containers (RPC) coupons, respectively. We attached Salmonella enterica serovar Typhimurium ATCC 14028 and serovar Heidelberg SL486 (parent and an antibiotic resistant marker strain) to plastic coupons (2.54 cm(2)) derived from previously used shipping containers by growing for 72 h in tryptic soy broth. The impact of the concentration of sanitizer on log reductions between unsanitized and sanitized coupons was evaluated by exposing attached S. Typhimurium cells to 200 ppm and 200,000 ppm sodium hypochlorite (NaClO). Differences in sanitizer effectiveness between serovars were also evaluated with attached S. Typhimurium compared to attached S. Heidelberg populations after being exposed to 200 ppm peracetic acid (PAA). Treatment with NaClO caused an average of 2.73 ± 0.23 log CFU of S. Typhimurium per coupon removed with treatment at 200 ppm while 3.36 ± 0.54 log CFU were removed at 200,000 ppm. Treatment with PAA caused an average of 2.62 ± 0.15 log CFU removed for S. Typhimurium and 1.41 ± 0.17 log CFU for S. Heidelberg (parent) and 1.61 ± 0.08 log CFU (marker). Lastly, scanning electron microscopy (SEM) was used to visualize cell attachment and coupon surface topography. SEM images showed that remaining attached cell populations were visible even after sanitizer application. Conventional plating and qPCR yielded similar levels of enumerated bacterial populations

  15. Same species, different diseases: how and why typhoidal and non-typhoidal Salmonella enterica serovars differ

    PubMed Central

    Gal-Mor, Ohad; Boyle, Erin C.; Grassl, Guntram A.

    2014-01-01

    Human infections by the bacterial pathogen Salmonella enterica represent major disease burdens worldwide. This highly ubiquitous species consists of more than 2600 different serovars that can be divided into typhoidal and non-typhoidal Salmonella (NTS) serovars. Despite their genetic similarity, these two groups elicit very different diseases and distinct immune responses in humans. Comparative analyses of the genomes of multiple Salmonella serovars have begun to explain the basis of the variation in disease manifestations. Recent advances in modeling both enteric fever and intestinal gastroenteritis in mice will facilitate investigation into both the bacterial- and host-mediated mechanisms involved in salmonelloses. Understanding the genetic and molecular mechanisms responsible for differences in disease outcome will augment our understanding of Salmonella pathogenesis, host immunity, and the molecular basis of host specificity. This review outlines the differences in epidemiology, clinical manifestations, and the human immune response to typhoidal and NTS infections and summarizes the current thinking on why these differences might exist. PMID:25136336

  16. Repression of flagella is a common trait in field isolates of Salmonella enterica serovar Dublin and is associated with invasive human infections.

    PubMed

    Yim, Lucía; Sasías, Sebastián; Martínez, Arací; Betancor, Laura; Estevez, Verónica; Scavone, Paola; Bielli, Alejandro; Sirok, Alfredo; Chabalgoity, José Alejandro

    2014-04-01

    The nontyphoidal Salmonella enterica serovar Dublin is adapted to cattle but infrequently infects humans, very often resulting in invasive infections with high levels of morbidity and mortality. A Salmonella-induced intestinal acute inflammatory response is postulated as a mechanism to prevent bacterial dissemination to systemic sites. In S. enterica serovar Typhimurium, flagella contribute to this response by providing motility and FliC-mediated activation of pattern recognition receptors. In this study, we found 4 Salmonella enterica isolates, with the antigenic formula 9,12:-:-, that, based on fliC sequence and multilocus sequence type (MLST) analyses, are aflagellate S. Dublin isolates. Interestingly, all were obtained from human bloodstream infections. Thus, we investigated the potential role of flagella in the unusual invasiveness exhibited by S. Dublin in humans by analyzing flagellation and proinflammatory properties of a collection of 10 S. Dublin human clinical isolates. We found that 4 of 7 blood isolates were aflagellate due to significantly reduced levels of fliC expression, whereas all 3 isolates from other sources were flagellated. Lack of flagella correlated with a reduced ability of triggering interleukin-8 (IL-8) and CCL20 chemokine expression in human intestinal Caco-2 cells and with reduced early inflammation in the ceca of streptomycin-pretreated C57/BL6 mice. These results indicate that flagella contribute to the host intestinal inflammatory response to Salmonella serovar Dublin and suggest that their absence may contribute to its systemic dissemination through dampening of the gut immune response. Analysis of FliC production in a collection of cattle isolates indicated that the aflagellate phenotype is widely distributed in field isolates of S. Dublin. PMID:24421045

  17. Repression of Flagella Is a Common Trait in Field Isolates of Salmonella enterica Serovar Dublin and Is Associated with Invasive Human Infections

    PubMed Central

    Sasías, Sebastián; Martínez, Arací; Betancor, Laura; Estevez, Verónica; Scavone, Paola; Bielli, Alejandro; Sirok, Alfredo; Chabalgoity, José Alejandro

    2014-01-01

    The nontyphoidal Salmonella enterica serovar Dublin is adapted to cattle but infrequently infects humans, very often resulting in invasive infections with high levels of morbidity and mortality. A Salmonella-induced intestinal acute inflammatory response is postulated as a mechanism to prevent bacterial dissemination to systemic sites. In S. enterica serovar Typhimurium, flagella contribute to this response by providing motility and FliC-mediated activation of pattern recognition receptors. In this study, we found 4 Salmonella enterica isolates, with the antigenic formula 9,12:−:−, that, based on fliC sequence and multilocus sequence type (MLST) analyses, are aflagellate S. Dublin isolates. Interestingly, all were obtained from human bloodstream infections. Thus, we investigated the potential role of flagella in the unusual invasiveness exhibited by S. Dublin in humans by analyzing flagellation and proinflammatory properties of a collection of 10 S. Dublin human clinical isolates. We found that 4 of 7 blood isolates were aflagellate due to significantly reduced levels of fliC expression, whereas all 3 isolates from other sources were flagellated. Lack of flagella correlated with a reduced ability of triggering interleukin-8 (IL-8) and CCL20 chemokine expression in human intestinal Caco-2 cells and with reduced early inflammation in the ceca of streptomycin-pretreated C57/BL6 mice. These results indicate that flagella contribute to the host intestinal inflammatory response to Salmonella serovar Dublin and suggest that their absence may contribute to its systemic dissemination through dampening of the gut immune response. Analysis of FliC production in a collection of cattle isolates indicated that the aflagellate phenotype is widely distributed in field isolates of S. Dublin. PMID:24421045

  18. Identification of genes associated with survival of salmonellaenterica serovar enteridis in chicken egg albumen

    SciTech Connect

    Clavijo, Raul I.; Loui, Cindy; Andersen, Gary L.; Riley, Lee W.; Lu, Sangwei

    2005-07-13

    Salmonella enterica consists of over 2,000 serovars that aremajor causes of morbidity and mortality associated with contaminatedfood. Despite similarities among serovars of Salmonella enterica, manydemonstrate unique host specificities, epidemiological characteristics,and clinical manifestations. One of the unique epidemiologicalcharacteristics of the serovar Enteritidis is that it is the onlybacterium routinely transmitted to humans through intact chicken eggs.Therefore, Salmonella enterica serovar Enteritidis must be able topersist inside chicken eggs to be transmitted to humans, and its survivalin egg is important for its transmission to the human population. Theability of Salmonella enterica serovar Enteritidis to survive in andtransmit through eggs may have contributed to its drastically increasedprevalence in the 1980s and 1990s. In the present study, usingtransposon-mediated mutagenesis, we have identified genes important forthe association of Salmonella enterica serovar Enteritidis with chickeneggs. Our results indicate that genes involved in cell wall structuraland functional integrity, and nucleic acid and amino acid metabolism areimportant for Salmonella enterica serovar Enteritidis to persist in eggalbumen. Two regions unique toSalmonella enterica serovar Enteritidiswere also identified, one of which enhanced the survival of a Salmonellaenterica serovar Typhimurium isolate in egg albumen. The implication ofour results to the serovar specificity of Salmonella enterica is alsoexplored in the present study.

  19. Diversity and antimicrobial susceptibility of Salmonella enterica serovars isolated from pig farms in Ibadan, Nigeria.

    PubMed

    Fashae, Kayode; Hendriksen, Rene S

    2014-01-01

    Animals including food animals play a significant role in the epidemiology of Salmonella enterica. The control requires identification of sources and institution of targeted interventions. This study investigates the diversity of S. enterica serovars, antimicrobial susceptibility, and occurrence of plasmid-mediated quinolone resistance (PMQR) genes in pigs in Ibadan, Nigeria. Pooled fresh pen floor fecal samples of pigs collected from 31 pig farms were cultured; the Salmonella isolates were serotyped and their antimicrobial susceptibility was determined. PMQR genes were screened by polymerase chain reaction. The 229 Salmonella isolates were made of 50 serovars predominated by rare serovars Salmonella Give (n = 36; 15.7 %), Salmonella Brancaster (n = 17; 7.4 %), Salmonella Colindale (n = 15; 6.6 %), Salmonella Elisaberthville (n = 13; 5.7 %), Salmonella Hillingdon (n = 13; 5.7 %), and Salmonella Kingston (n = 13; 5.7 %). The most widely distributed serovars among the farms were Salmonella Give (six farms) and Salmonella Elisaberthville (six farms). Resistance to chloramphenicol, sulfonamides, nalidixic acid, streptomycin, and tetracycline ranged from 11.6 % (n = 26) to 22.8 % (n = 51). Resistance ciprofloxacin and gentamicin was low (n = 2; 0.9 %). Multiply resistant isolates included Salmonella Kentucky, the most resistant serovar. qnrB19 was found in two isolates of Salmonella Corvallis and one isolate of Salmonella Larochelle, respectively, while qnrS1 was found in two isolates of Salmonella Derby. Other PMQR genes were not detected. Pigs constitute an important source of diverse Salmonella serovars in Ibadan. The isolates were more resistant to old antimicrobials with some multiple resistant. Control measures and regulation of antimicrobials are warranted. PMID:23893398

  20. Antimicrobial resistance-conferring plasmids with similarity to virulence plasmids from avian pathogenic Escherichia coli strains in Salmonella enterica serovar Kentucky isolates from poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica, a leading cause of food-borne gastroenteritis worldwide, may be found in any raw food of animal, vegetable, or fruit origin. Salmonella serovars differ in distribution, virulence, and host specificity. Salmonella enterica serovar Kentucky, though often found in the food supply, ...

  1. Complete Genome Sequence of Salmonella enterica subsp. enterica Serovar Indiana C629, a Carbapenem-Resistant Bacterium Isolated from Chicken Carcass in China

    PubMed Central

    Liu, Feng; Peng, Zixin; Li, Fengqin

    2016-01-01

    The carbapenem-resistant Salmonella enterica subsp. enterica serovar Indiana strain C629 was isolated from a chicken carcass collected from a slaughterhouse in Qingdao, China. The complete genome sequence of C629 contains a circular 4,791,723-bp chromosome and a circular 210,106-bp plasmid. Genes involved in carbapenem resistance of this bacterium were identified by whole-genome analysis. PMID:27417837

  2. A Five-Strain Probiotic Combination Reduces Pathogen Shedding and Alleviates Disease Signs in Pigs Challenged with Salmonella enterica Serovar Typhimurium▿

    PubMed Central

    Casey, Pat G.; Gardiner, Gillian E.; Casey, Garrett; Bradshaw, Bernard; Lawlor, Peadar G.; Lynch, P. Brendan; Leonard, Finola C.; Stanton, Catherine; Ross, R. Paul; Fitzgerald, Gerald F.; Hill, Colin

    2007-01-01

    Salmonella spp. infection is a major cause of gastroenteritis, with many thousands of cases reported in the European Union every year. The use of probiotics offers the potential to improve this situation. Here, we investigate the effects of oral treatment of pigs with a defined lactic acid bacteria culture mixture on both clinical and microbiological signs of Salmonella enterica serovar Typhimurium infection. Fifteen weaned pigs blocked by sex and weight were administered control milk or a mixture of five probiotic strains as either a milk fermentate or milk suspension for a total of 30 days. The mixture consisted of two strains of Lactobacillus murinus and one strain each of Lactobacillus salivarius subsp. salivarius, Lactobacillus pentosus, and Pediococcus pentosaceous. Following probiotic administration for 6 days, animals were challenged orally with serovar Typhimurium; the health of the animals and the microbiological composition of their feces were monitored for 23 days postinfection. Animals treated with probiotic showed reduced incidence, severity, and duration of diarrhea. These animals also gained weight at a greater rate than control pigs administered skim milk. Mean fecal numbers of Salmonella were significantly reduced in probiotic-treated animals at 15 days postinfection (P = 0.01). The administered probiotic bacteria improved both the clinical and microbiological outcome of Salmonella infection. These strains offer significant benefit for use in the food industry and may have potential in human applications. PMID:17261517

  3. Conjugal Transfer of the Pathogenicity Island ROD21 in Salmonella enterica serovar Enteritidis Depends on Environmental Conditions

    PubMed Central

    Salazar-Echegarai, Francisco J.; Tobar, Hugo E.; Nieto, Pamela A.; Riedel, Claudia A.; Bueno, Susan M.

    2014-01-01

    Unstable pathogenicity islands are chromosomal elements that can be transferred from one bacterium to another. Salmonella enterica serovar Enteritidis (S. Enteritidis) is a pathogenic bacterium containing such unstable pathogenicity islands. One of them, denominated ROD21, is 26.5 kb in size and capable of excising from the chromosome in certain culture conditions, as well as during bacterial infection of phagocytic cells. In this study we have evaluated whether ROD21 can be effectively transferred from one bacterium to another. We generated a donor and several recipient strains of S. Enteritidis to carry out transfer assays in liquid LB medium. These assays showed that ROD21 is effectively transferred from donor to recipient strains of S. Enteritidis and S. Typhimurium. When Escherichia coli was used as the recipient strain, ROD21 transfer failed to be observed. Subsequently, we showed that a conjugative process was required for the transfer of the island and that changes in temperature and pH increased the transfer frequency between Salmonella strains. Our data indicate that ROD21 is an unstable pathogenicity island that can be transferred by conjugation in a species-specific manner between Salmonellae. Further, ROD21 transfer frequency increases in response to environmental changes, such as pH and temperature. PMID:24705125

  4. Characterization of isolates of Salmonella enterica serovar Stanley, a serovar endemic to Asia and associated with travel.

    PubMed

    Hendriksen, Rene S; Le Hello, Simon; Bortolaia, Valeria; Pulsrikarn, Chaiwat; Nielsen, Eva Møller; Pornruangmong, Srirat; Chaichana, Phattharaporn; Svendsen, Christina Aaby; Weill, François-Xavier; Aarestrup, Frank M

    2012-03-01

    Salmonella enterica serovar Stanley (S. Stanley) is a common serovar in Southeast Asia and was the second most common serovar implicated in human salmonellosis in Thailand in the years 2002 to 2007. In contrast, this serovar is relatively uncommon in Europe. The objective of this study was to characterize a collection of S. Stanley strains isolated from Thai (n = 62), Danish (n = 39), and French (n = 24) patients to gain a broader understanding of the genetic diversity, population dynamics, and susceptibility to antimicrobials. All isolates were characterized by pulsed-field gel electrophoresis and antimicrobial susceptibility testing. The molecular mechanisms of resistance to extended-spectrum cephalosporins and plasmid-mediated resistance to quinolones were characterized by PCR and sequencing. Plasmid profiling, replicon typing, and microarray analysis were used to characterize the genetic mechanisms of antimicrobial resistance in 10 extended-spectrum cephalosporinase-producing isolates. Considerable genetic diversity was observed among the isolates characterized with 91 unique XbaI pulsed-field gel electrophoresis (PFGE) patterns, including 17 distinct clusters consisting of two to seven indistinguishable isolates. We found some of the S. Stanley isolates isolated from patients in Europe were acquired during travel to Southeast Asia, including Thailand. The presence of multiple plasmid lineages carrying the extended-spectrum cephalosporinase-encoding bla(CMY-2) gene in S. Stanley isolates from the central part of Thailand was confirmed. Our results emphasize that Thai authorities, as well as authorities in other countries lacking prudent use of antimicrobials, should improve the ongoing efforts to regulate antimicrobial use in agriculture and in clinical settings to limit the spread of multidrug-resistant Salmonella isolates and plasmids among humans and pigs in Thailand and abroad. PMID:22205822

  5. Emergence of Ciprofloxacin-Resistant Salmonella enterica Serovar Typhi in Italy

    PubMed Central

    García-Fernández, Aurora; Gallina, Silvia; Owczarek, Slawomir; Dionisi, Anna Maria; Benedetti, Ildo; Decastelli, Lucia; Luzzi, Ida

    2015-01-01

    In developed countries, typhoid fever is often associated with persons who travel to endemic areas or immigrate from them. Typhoid fever is a systemic infection caused by Salmonella enterica serovar Typhi. Because of the emergence of antimicrobial resistance to standard first-line drugs, fluoroquinolones are the drugs of choice. Resistance to ciprofloxacin by this Salmonella serovar represents an emerging public health issue. Two S. enterica ser. Typhi strains resistant to ciprofloxacin (CIP) were reported to the Italian surveillance system for foodborne and waterborne diseases (EnterNet-Italia) in 2013. The strains were isolated from two Italian tourists upon their arrival from India. A retrospective analysis of 17 other S. enterica ser. Typhi strains isolated in Italy during 2011–2013 was performed to determine their resistance to CIP. For this purpose, we assayed for susceptibility to antimicrobial agents and conducted PCR and nucleotide sequence analyses. Moreover, all strains were typed using pulsed-field gel electrophoresis to evaluate possible clonal relationships. Sixty-eight percent of the S. enterica ser. Typhi strains were resistant to CIP (MICs, 0.125–16 mg/L), and all isolates were negative for determinants of plasmid-mediated quinolone resistance. Analysis of sequences encoding DNA gyrase and topoisomerase IV subunits revealed mutations in gyrA, gyrB, and parC. Thirteen different clonal groups were detected, and the two CIP-resistant strains isolated from the individuals who visited India exhibited the same PFGE pattern. Because of these findings, the emergence of CIP-resistant S. enterica ser. Typhi isolates in Italy deserves attention, and monitoring antibiotic susceptibility is important for efficiently managing cases of typhoid fever. PMID:26121266

  6. Emergence of Ciprofloxacin-Resistant Salmonella enterica Serovar Typhi in Italy.

    PubMed

    García-Fernández, Aurora; Gallina, Silvia; Owczarek, Slawomir; Dionisi, Anna Maria; Benedetti, Ildo; Decastelli, Lucia; Luzzi, Ida

    2015-01-01

    In developed countries, typhoid fever is often associated with persons who travel to endemic areas or immigrate from them. Typhoid fever is a systemic infection caused by Salmonella enterica serovar Typhi. Because of the emergence of antimicrobial resistance to standard first-line drugs, fluoroquinolones are the drugs of choice. Resistance to ciprofloxacin by this Salmonella serovar represents an emerging public health issue. Two S. enterica ser. Typhi strains resistant to ciprofloxacin (CIP) were reported to the Italian surveillance system for foodborne and waterborne diseases (EnterNet-Italia) in 2013. The strains were isolated from two Italian tourists upon their arrival from India. A retrospective analysis of 17 other S. enterica ser. Typhi strains isolated in Italy during 2011-2013 was performed to determine their resistance to CIP. For this purpose, we assayed for susceptibility to antimicrobial agents and conducted PCR and nucleotide sequence analyses. Moreover, all strains were typed using pulsed-field gel electrophoresis to evaluate possible clonal relationships. Sixty-eight percent of the S. enterica ser. Typhi strains were resistant to CIP (MICs, 0.125-16 mg/L), and all isolates were negative for determinants of plasmid-mediated quinolone resistance. Analysis of sequences encoding DNA gyrase and topoisomerase IV subunits revealed mutations in gyrA, gyrB, and parC. Thirteen different clonal groups were detected, and the two CIP-resistant strains isolated from the individuals who visited India exhibited the same PFGE pattern. Because of these findings, the emergence of CIP-resistant S. enterica ser. Typhi isolates in Italy deserves attention, and monitoring antibiotic susceptibility is important for efficiently managing cases of typhoid fever. PMID:26121266

  7. Isolation of Salmonella enterica serovar Enteritidis from House Flies (Musca domestica) Found in Rooms Containing Salmonella serovar Enteritidis-challenged hens.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    House flies (Musca domestica) released into rooms containing hens challenged with Salmonella enterica serovar Enteritidis (S. enteritidis) rapidly became contaminated with S. enteritidis. Forty to 50% of the flies were contaminated at 48 hours which increased to 50-70% at 4 and 7 days post exposur...

  8. Chromosomal Rearrangements in Salmonella enterica Serovar Typhi Strains Isolated from Asymptomatic Human Carriers

    PubMed Central

    Matthews, T. David; Rabsch, Wolfgang; Maloy, Stanley

    2011-01-01

    ABSTRACT Host-specific serovars of Salmonella enterica often have large-scale chromosomal rearrangements that occur by recombination between rrn operons. Two hypotheses have been proposed to explain these rearrangements: (i) replichore imbalance from horizontal gene transfer drives the rearrangements to restore balance, or (ii) the rearrangements are a consequence of the host-specific lifestyle. Although recent evidence has refuted the replichore balance hypothesis, there has been no direct evidence for the lifestyle hypothesis. To test this hypothesis, we determined the rrn arrangement type for 20 Salmonella enterica serovar Typhi strains obtained from human carriers at periodic intervals over multiple years. These strains were also phage typed and analyzed for rearrangements that occurred over long-term storage versus routine culturing. Strains isolated from the same carrier at different time points often exhibited different arrangement types. Furthermore, colonies isolated directly from the Dorset egg slants used to store the strains also had different arrangement types. In contrast, colonies that were repeatedly cultured always had the same arrangement type. Estimated replichore balance of isolated strains did not improve over time, and some of the rearrangements resulted in decreased replicore balance. Our results support the hypothesis that the restricted lifestyle of host-specific Salmonella is responsible for the frequent chromosomal rearrangements in these serovars. PMID:21652779

  9. Outbreaks of monophasic Salmonella enterica serovar 4,[5],12:i:- in Luxembourg, 2006.

    PubMed

    Mossong, J; Marques, P; Ragimbeau, C; Huberty-Krau, P; Losch, S; Meyer, G; Moris, G; Strottner, C; Rabsch, W; Schneider, F

    2007-06-01

    A monophasic Salmonella enterica serovar 4,[5],12:i:- phage type DT193 emerged as the dominant serovar in Luxembourg in 2006, when it caused two major outbreaks involving 133 laboratory-confirmed human cases, 24 hospitalisations, and one death. The outbreak strain had an uncommon pulsed-field gel electrophoresis pattern STYMXB.0031 and antibiotic resistance profile ASSuT. A high proportion of cases were clustered in institutions for the elderly and in day-care centers. Strains identical to the outbreak strain were recovered from two control meals, a nappy changing table, retail sausages and caecal porcine samples at an abattoir. Locally produced pork meat is strongly suspected to have been the vehicle for the outbreaks, although the precise mechanisms remain unclear. PMID:17991400

  10. Extended-Spectrum Cephalosporin-Resistant Salmonella enterica serovar Heidelberg Strains, the Netherlands(1).

    PubMed

    Liakopoulos, Apostolos; Geurts, Yvon; Dierikx, Cindy M; Brouwer, Michael S M; Kant, Arie; Wit, Ben; Heymans, Raymond; van Pelt, Wilfrid; Mevius, Dik J

    2016-07-01

    Extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg strains (JF6X01.0022/XbaI.0251, JF6X01.0326/XbaI.1966, JF6X01.0258/XbaI.1968, and JF6X01.0045/XbaI.1970) have been identified in the United States with pulsed-field gel electrophoresis. Our examination of isolates showed introduction of these strains in the Netherlands and highlight the need for active surveillance and intervention strategies by public health organizations. PMID:27314180

  11. Extended-Spectrum Cephalosporin-Resistant Salmonella enterica serovar Heidelberg Strains, the Netherlands1

    PubMed Central

    Geurts, Yvon; Dierikx, Cindy M.; Brouwer, Michael S.M.; Kant, Arie; Wit, Ben; Heymans, Raymond; van Pelt, Wilfrid; Mevius, Dik J.

    2016-01-01

    Extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg strains (JF6X01.0022/XbaI.0251, JF6X01.0326/XbaI.1966, JF6X01.0258/XbaI.1968, and JF6X01.0045/XbaI.1970) have been identified in the United States with pulsed-field gel electrophoresis. Our examination of isolates showed introduction of these strains in the Netherlands and highlight the need for active surveillance and intervention strategies by public health organizations. PMID:27314180

  12. Salmonella enterica serovar Typhi Ty21a expressing human papillomavirus type 16 L1 as a potential live vaccine against cervical cancer and typhoid fever.

    PubMed

    Fraillery, Dominique; Baud, David; Pang, Susana Yuk-Ying; Schiller, John; Bobst, Martine; Zosso, Nathalie; Ponci, Françoise; Nardelli-Haefliger, Denise

    2007-10-01

    Human papillomavirus (HPV) vaccines based on L1 virus-like particles (VLPs) can prevent HPV-induced genital neoplasias, the precursors of cervical cancer. However, most cervical cancers occur in developing countries, where the implementation of expensive vaccines requiring multiple injections will be difficult. A live Salmonella-based vaccine could be a lower-cost alternative. We previously demonstrated that high HPV type 16 (HPV16)-neutralizing titers are induced after a single oral immunization of mice with attenuated Salmonella enterica serovar Typhimurium strains expressing a codon-optimized version of HPV16 L1 (L1S). To allow the testing of this type of vaccine in women, we constructed a new L1-expressing plasmid, kanL1S, and tested kanL1S recombinants of three Salmonella enterica serovar Typhi vaccine strains shown to be safe in humans, i.e., Ty21a, the actual licensed typhoid vaccine, and two highly immunogenic typhoid vaccine candidates, Ty800 and CVD908-htrA. In an intranasal mouse model of Salmonella serovar Typhi infection, Ty21a kanL1S was unique in inducing HPV16-neutralizing antibodies in serum and genital secretions, while anti-Salmonella responses were similar to those against the parental Ty21a vaccine. Electron microscopy examination of Ty21a kanL1S lysates showed that L1 assembled in capsomers and capsomer aggregates but not well-ordered VLPs. Comparison to the neutralizing antibody response induced by purified HPV16 L1 VLP immunizations in mice suggests that Ty21a kanL1S may be an effective prophylactic HPV vaccine. Ty21a has been widely used against typhoid fever in humans with a remarkable safety record. These finds encourage clinical testing of Ty21a kanL1S as a combined typhoid fever/cervical cancer vaccine with the potential for worldwide application. PMID:17687110

  13. Safety and immunogenicity of an attenuated Salmonella enterica serovar Paratyphi A vaccine candidate.

    PubMed

    Xiong, Kun; Chen, Zhijin; Zhu, Chunyue; Li, Jianhua; Hu, Xiaomei; Rao, Xiancai; Cong, Yanguang

    2015-09-01

    Enteric fever caused by Salmonella enterica serovar Paratyphi A has progressively increased in recent years and became a global health issue. Currently licensed typhoid vaccines do not confer adequate cross-immunoprotection against S. Paratyphi A infection. Therefore, vaccines specifically against enteric fever caused by S. Paratyphi A are urgently needed. In the present study, an attenuated vaccine strain was constructed from S. Paratyphi A CMCC50093 by the deletions of aroC and yncD. The obtained strain SPADD01 showed reduced survival within THP-1 cells and less bacterial burden in spleens and livers of infected mice compared with the wild-type strain. The 50% lethal doses of SPADD01 and the wild-type strain were assessed using a murine infection model. The virulence of SPADD01 is approximately 40,000-fold less than that of the wild-type strain. In addition, SPADD01 showed an excellent immunogenicity in mouse model. Single intranasal inoculation elicited striking humoral and mucosal immune responses in mice and yielded effective protection against lethal challenge of the wild-type strain. A high level of cross-reactive humoral immune response against LPS of Salmonella enterica serovar Typhi was also detected in immunized mice. However, SPADD01 vaccination only conferred a low level of cross-protection against S. Typhi. Our data suggest that SPADD01 is a promising vaccine candidate against S. Paratyphi A infection and deserves further evaluation in clinical trial. To date, no study has demonstrated a good cross-protection between serovars of S. Typhi and S. Paratyphi A, suggesting that the dominant protective antigens of both serovars are likely different and need to be defined in future study. PMID:26239100

  14. Slc11a1 limits intracellular growth of Salmonella enterica sv. Typhimurium by promoting macrophage immune effector functions and impairing bacterial iron acquisition

    PubMed Central

    Nairz, Manfred; Fritsche, Gernot; Crouch, Marie-Laure V.; Barton, Howard C.; Fang, Ferric C.; Weiss, Günter

    2009-01-01

    The natural-resistance associated macrophage protein 1, Slc11a1, is a phagolysosomal transporter for protons and divalent ions including iron, that confers host protection against diverse intracellular pathogens including Salmonella. We investigated and compared the regulation of iron homeostasis and immune function in RAW264.7 murine phagocytes stably transfected with non-functional Slc11a1 and functional Slc11a1 controls in response to an infection with Salmonella enterica serovar Typhimurium (S. Typhimurium). We report that macrophages lacking functional Slc11a1 displayed an increased expression of transferrin receptor 1, resulting in enhanced acquisition of transferrin-bound iron. In contrast, cellular iron release mediated via ferroportin 1 was significantly lower in Salmonella-infected Slc11a1-negative macrophages in comparison to phagocytes bearing Slc11a1. Lack of Slc11a1 led to intracellular persistence of S. Typhimurium within macrophages which was paralleled by a reduced formation of nitric oxide, tumour necrosis factor-alpha and interleukin-6 in Slc11a1-negative macrophages following Salmonella infection, whereas interleukin-10 production was increased. Moreover, Slc11a1-negative phagocytes exhibited higher cellular iron content, resulting in increased iron acquisition by intracellular Salmonella. Our observations indicate a bifunctional role for Slc11a1 within phagocytes. Slc11a restricts iron availability, which firstly augments pro-inflammatory macrophage effector functions and secondly concomitantly limits microbial iron access. PMID:19500110

  15. Evaluation of aroA deletion mutant of Salmonella enterica subspecies enterica serovar Abortusequi for its vaccine candidate potential.

    PubMed

    Alam, Javad; Singh, B R; Hansda, D; Singh, V P; Verma, J C

    2009-11-01

    The present study on a defined deletion aroA mutant (B-26) of Salmonella enterica subspecies enterica serovar Abortusequi (S. Abortusequi) for residual virulence and safety in experimental model revealed that the virulence of the strain was at no difference in any of the cell assays (caprine alveolar macrophages, bovine alveolar macrophages, guinea pig blood mononuclear cells and horse blood mononuclear cells) than that of its parent virulence plasmid cured (S-787) and wild type (E-156) strains. The mutant did not cause any apparent illness in baby guinea pigs (15 days old), adult male and female guinea pigs and also not in pregnant (54-55 days of gestation) guinea pigs through oral (4.2 x 10(9) cfu/ animal) and intramuscular (im) routes (4.2 x 10(7) cfu/ animal). In pregnant females the mutant also induced abortion as its parent (E-156) though to lesser extent (33%) than the parent strain (100%) on inoculation through intravaginal (4.2 x 10(9) cfu/ animal) and intraperitoneal (4.2 x 10(7) cfu/ animal) routes. The babies born from mutant inoculated mothers survived better and were also resistant to intraperitoneal lethal challenge (7.82 x 10(9) cfu/ animal) with 100% protection. Female guinea pigs challenged after 135-165 days of inoculation with the mutant afforded 100% protection from abortion and mortality caused by lethal infection (7.82 x 10(9) cfu/ animal) of wild type S. enterica Abortusequi (E-156). The study revealed that aroA mutant (B-26) was safe through oral and im routes for immunization and afforded 100% protection against salmonellosis for more than 5.5 months in guinea pigs. Although immunization with aroA mutant in experimental model afforded good protection against abortion and mortality induced by S. Abortusequi, further studies are needed in horses to exploit the strain's vaccine potential in the natural host. PMID:20099460

  16. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within the Uni...

  17. Identification of SNPs in two Salmonella enterica serovar Enteritidis PT13a pathotypes that point to epidemiological trends.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the most frequent cause of salmonellosis in the world. Epidemiological data from the Centers for Disease Control indicates that the incidence of illness from S. Enteritidis in the United States increased during 2005 despi...

  18. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within the Unit...

  19. Critical role of glycogen synthase kinase-3ß in regulating the avian heterophil response to Salmonella enterica serovar Enteritidis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A microarray-assisted gene expression screen of chicken heterophils revealed glycogen synthase kinase-3ß (GSK-3ß), a multifunctional Ser/Thr kinase, to be consistently up-regulated 30-180 min following stimulation with Salmonella enterica serovar Enteritidis (S. Enteritidis). The present study was ...

  20. First report of extended-spectrum-beta-lactamase-producing Salmonella enterica serovar Kentucky isolated from poultry in Ireland.

    PubMed

    Boyle, F; Morris, D; O'Connor, J; Delappe, N; Ward, J; Cormican, M

    2010-01-01

    Therapy of invasive human salmonellosis is complicated by increasing antimicrobial resistance. Food animals are the principal source of infection with nontyphoid Salmonella. We report the emergence of broad-spectrum-cephalosporin resistance in Salmonella enterica serovar Kentucky in poultry in Ireland. PMID:19884382

  1. Clinical Isolates of Salmonella enterica Serovar Agona Producing NDM-1 Metallo-β-Lactamase: First Report from Pakistan

    PubMed Central

    Khan, Erum; Jabeen, Kauser; Bhawan, Pushpa; Hopkins, Katie L.; Day, Martin; Nasir, Amna; Meunier, Daniele; Woodford, Neil

    2014-01-01

    We report two cases of infantile diarrhea due to multidrug-resistant, NDM-1 metallo-β-lactamase-producing Salmonella enterica serovar Agona from Pakistan. This study alerts toward possible risk of NDM-1 transmission to enteric fever pathogens and encourages microbiologists to consider active screening of carbapenem resistance in nontyphoidal Salmonella isolates. PMID:25378577

  2. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens can result in illness in humans who consume them. Although the incidence of this pathogen within the United States has not been as high as it ...

  3. First Report of Human Infection with Salmonella enterica Serovar Apapa Resulting from Exposure to a Pet Lizard▿

    PubMed Central

    Cooke, Fiona J.; De Pinna, Elizabeth; Maguire, Clare; Guha, Simantee; Pickard, Derek J.; Farrington, Mark; Threlfall, E. John

    2009-01-01

    We present the first documented human case of Salmonella enterica serovar Apapa infection, isolated concurrently from a hospital inpatient and a pet lizard. The isolates were identical by biochemical profiling and pulsed-field gel electrophoresis. This rare serotype is known to be associated with reptiles. The current practice for avoiding reptile-associated infections is reviewed. PMID:19535527

  4. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs that are contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within...

  5. Sensitive Detection and Serovar Differentiation of Typhoidal and Nontyphoidal Salmonella enterica Species Using 16S rRNA Gene PCR Coupled with High-Resolution Melt Analysis

    PubMed Central

    Masek, Billie J.; Hardick, Justin; Won, Helen; Yang, Samuel; Hsieh, Yu-Hsiang; Rothman, Richard E.; Gaydos, Charlotte A.

    2015-01-01

    Salmonella enterica species infections are a significant public health problem causing high morbidity rates worldwide and high mortality rates in the developing world. These infections are not always rapidly diagnosed as a cause of bloodstream infections because of the limitations of blood culture, which greatly affects clinical care as a result of treatment delays. A molecular diagnostic assay that could rapidly detect and identify S. enterica species infections as a cause of sepsis is needed. Nine typhoidal and nontyphoidal S. enterica serovars were used to establish the limit of detection (LOD) of a previously published 16S rRNA gene PCR (16S PCR) in mock whole blood specimens. In addition, 16 typhoidal and nontyphoidal S. enterica serovars were used to evaluate the serovar differentiation capability of 16S PCR coupled with high-resolution melt analysis. The overall LOD of 16S PCR for the nine typhoidal and nontyphoidal S. enterica serovars analyzed was <10 colony-forming units per milliliter (CFU/mL) in mock whole blood specimens, with the lowest and highest LOD at <1 CFU/mL and 9 CFU/mL, respectively. By high-resolution melt analysis, the typhoidal and nontyphoidal S. enterica serovar groups analyzed each generated a unique grouping code, allowing for serovar-level identification. 16S PCR coupled with high-resolution melt analysis could be a useful molecular diagnostic that could enhance the current diagnostic, treatment, and surveillance methods of S. enterica bloodstream infections. PMID:24365382

  6. Characterization of the ELPhiS prophage from Salmonella enterica serovar Enteritidis strain LK5.

    PubMed

    Hanna, L Farris; Matthews, T David; Dinsdale, Elizabeth A; Hasty, David; Edwards, Robert A

    2012-03-01

    Phages are a primary driving force behind the evolution of bacterial pathogens by transferring a variety of virulence genes into their hosts. Similar to other bacterial genomes, the Salmonella enterica serovar Enteritidis LK5 genome contains several regions that are homologous to phages. Although genomic analysis demonstrated the presence of prophages, it was unable to confirm which phage elements within the genome were viable. Genetic markers were used to tag one of the prophages in the genome to allow monitoring of phage induction. Commonly used laboratory strains of Salmonella were resistant to phage infection, and therefore a rapid screen was developed to identify susceptible hosts. This approach showed that a genetically tagged prophage, ELPhiS (Enteritidis lysogenic phage S), was capable of infecting Salmonella serovars that are diverse in host range and virulence and has the potential to laterally transfer genes between these serovars via lysogenic conversion. The rapid screen approach is adaptable to any system with a large collection of isolates and may be used to test the viability of prophages found by sequencing the genomes of various bacterial pathogens. PMID:22247173

  7. High-Throughput CRISPR Typing of Mycobacterium tuberculosis Complex and Salmonella enterica Serotype Typhimurium.

    PubMed

    Sola, Christophe; Abadia, Edgar; Le Hello, Simon; Weill, François-Xavier

    2015-01-01

    Spoligotyping was developed almost 18 years ago and still remains a popular first-lane genotyping technique to identify and subtype Mycobacterium tuberculosis complex (MTC) clinical isolates at a phylogeographic level. For other pathogens, such as Salmonella enterica, recent studies suggest that specifically designed spoligotyping techniques could be interesting for public health purposes. Spoligotyping was in its original format a reverse line-blot hybridization method using capture probes designed on "spacers" and attached to a membrane's surface and a PCR product obtained from clustered regularly interspaced short palindromic repeats (CRISPRs). Cowan et al. and Fabre et al. were the first to propose a high-throughput Spoligotyping method based on microbeads for MTC and S. enterica serotype Typhimurium, respectively. The main advantages of the high-throughput Spoligotyping techniques we describe here are their low cost, their robustness, and the existence (at least for MTC) of very large databases that allow comparisons between spoligotypes from anywhere. PMID:25981468

  8. Multidrug resistance in Salmonella enterica serotype Typhimurium from humans in France (1993 to 2003).

    PubMed

    Weill, François-Xavier; Guesnier, Françoise; Guibert, Véronique; Timinouni, Mohammed; Demartin, Marie; Polomack, Lucette; Grimont, Patrick A D

    2006-03-01

    The aim of this study was to determine the distribution of the antimicrobial resistance phenotypes (R types), the phage types and XbaI-pulsed-field gel electrophoresis (PFGE) types, the genes coding for resistance to beta-lactams and to quinolones, and the class 1 integrons among a representative sample of Salmonella enterica serotype Typhimurium isolates collected from humans in 2002 through the French National Reference Center for Salmonella (NRC-Salm) network. The trends in the evolution of antimicrobial resistance of serotype Typhimurium were reviewed by using NRC-Salm data from 1993, 1997, 2000, and 2003. In 2002, 3,998 isolates of serotype Typhimurium were registered at the NRC-Salm among 11,775 serotyped S. enterica isolates (34%). The most common multiple antibiotic resistance pattern was resistance to amoxicillin, chloramphenicol, streptomycin and spectinomycin, sulfonamides, and tetracycline (ACSSpSuTe R type), with 156 isolates (48.8%). One isolate resistant to extended-spectrum cephalosporins due to the production of TEM-52 extended-spectrum beta-lactamase was detected (0.3%), and one multidrug-resistant isolate was highly resistant to ciprofloxacin (MIC > 32 mg/liter). We found that 57.2% of the isolates tested belonged to the DT104 clone. The main resistance pattern of DT104 isolates was R type ACSSpSuTe (83.2%). However, evolutionary changes have occurred within DT104, involving both loss (variants of Salmonella genomic island 1) and acquisition of genes for drug resistance to trimethoprim or to quinolones. PFGE profile X1 was the most prevalent (74.5%) among DT104 isolates, indicating the need to use a more discriminatory subtyping method for such isolates. Global data from the NRC-Salm suggested that DT104 was the main cause of multidrug resistance in serotype Typhimurium from humans from at least 1997 to 2003, with a roughly stable prevalence during this period. PMID:16517842

  9. RosE represses Std fimbrial expression in Salmonella enterica serotype Typhimurium

    PubMed Central

    Chessa, Daniela; Winter, Maria G; Nuccio, Sean-Paul; Tükel, Çagla; Bäumler, Andreas J

    2008-01-01

    The Salmonella enterica serotype Typhimurium (S. typhimurium) genome contains a large repertoire of putative fimbrial operons that remain poorly characterized because they are not expressed in vitro. In this study, insertions that induced expression of the putative stdABCD fimbrial operon were identified from a random bank of transposon mutants by screening with immuno-magnetic particles for ligand expression (SIMPLE). Transposon insertions upstream of csgC and lrhA or within dam, setB and STM4463 (renamed rosE) resulted in expression of StdA and its assembly into fimbrial filaments on the cell surface. RosE is a novel negative regulator of Std fimbrial expression as indicated by its repression of a std::lacZ reporter construct and by binding of the purified protein to a DNA region upstream of the stdA start codon. Expression of Std fimbriae in the rosE mutant resulted in increased attachment of S. typhimurium to human colonic epithelial cell lines (T-84 and CaCo-2). A rosE mutant exhibited a reduced ability to compete with virulent S. typhimurium for colonization of murine organs, while no defect was observed when both competing strains carried a stdAB deletion. These data suggest that a tight control of Std fimbrial expression mediated by RosE is required during host pathogen interaction. PMID:18331470

  10. Isolation and Characterization of Antimicrobial-Resistant Nontyphoidal Salmonella enterica Serovars from Imported Food Products.

    PubMed

    Bae, Dongryeoul; Kweon, Ohgew; Khan, Ashraf A

    2016-08-01

    The objective of this study was to determine antimicrobial resistance and elucidate the resistance mechanism in nontyphoidal Salmonella enterica serovars isolated from food products imported into the United States from 2011 to 2013. Food products contaminated with antimicrobial-resistant nontyphoidal S. enterica were mainly imported from Taiwan, Indonesia, Vietnam, and China. PCR, DNA sequencing, and plasmid analyses were used to characterize antimicrobial resistance determinants. Twentythree of 110 S. enterica isolates were resistant to various antimicrobial classes, including β-lactam, aminoglycoside, phenicol, glycopeptide, sulfonamide, trimethoprim, and/or fluoroquinolone antimicrobial agents. Twelve of the isolates were multidrug resistant strains. Antimicrobial resistance determinants blaTEM-1, blaCTX-M-9, blaOXA-1, tetA, tetB, tetD, dfrA1, dfrV, dhfrI, dhfrXII, drf17, aadA1, aadA2, aadA5, orfC, qnrS, and mutations of gyrA and parC were detected in one or more antimicrobial-resistant nontyphoidal S. enterica strains. Plasmid profiles revealed that 12 of the 23 antimicrobial-resistant strains harbored plasmids with incompatibility groups IncFIB, IncHI1, IncI1, IncN, IncW, and IncX. Epidemiologic and antimicrobial resistance monitoring data combined with molecular characterization of antimicrobial resistance determinants in Salmonella strains isolated from imported food products may provide information that can be used to establish or implement food safety programs to improve public health. PMID:27497122

  11. Circulating γδ T Cells in Response to Salmonella enterica Serovar Enteritidis Exposure in Chickens

    PubMed Central

    Berndt, Angela; Pieper, Jana; Methner, Ulrich

    2006-01-01

    γδ T cells are considered crucial to the outcome of various infectious diseases. The present study was undertaken to characterize γδ (T-cell receptor 1+ [TCR1+]) T cells phenotypically and functionally in avian immune response. Day-old chicks were orally immunized with Salmonella enterica serovar Enteritidis live vaccine or S. enterica serovar Enteritidis wild-type strain and infected using the S. enterica serovar Enteritidis wild-type strain on day 44 of life. Between days 3 and 71, peripheral blood was examined flow cytometrically for the occurrence of γδ T-cell subpopulations differentiated by the expression of T-cell antigens. Three different TCR1+ cell populations were found to display considerable variation regarding CD8α antigen expression: (i) CD8α+high TCR1+ cells, (ii) CD8α+dim TCR1+ cells, and (iii) CD8α− TCR1+ cells. While most of the CD8α+high TCR1+ cells expressed the CD8αβ heterodimeric antigen, the majority of the CD8α+dim TCR1+ cells were found to express the CD8αα homodimeric form. After immunization, a significant increase of CD8αα+high γδ T cells was observed within the CD8α+high TCR1+ cell population. Quantitative reverse transcription-PCR revealed reduced interleukin-7 receptor α (IL-7Rα) and Bcl-x expression and elevated IL-2Rα mRNA expression of the CD8αα+high γδ T cells. Immunohistochemical analysis demonstrated a significant increase of CD8α+ and TCR1+ cells in the cecum and spleen and a decreased percentage of CD8β+ T cells in the spleen after Salmonella immunization. After infection of immunized animals, immune reactions were restricted to intestinal tissue. The study showed that Salmonella immunization of very young chicks is accompanied by an increase of CD8αα+high γδ T cells in peripheral blood, which are probably activated, and thus represent an important factor for the development of a protective immune response to Salmonella organisms in chickens. PMID:16790770

  12. RpoE may promote flagellar gene expression in Salmonella enterica serovar typhi under hyperosmotic stress.

    PubMed

    Du, Hong; Sheng, Xiumei; Zhang, Haifang; Zou, Xin; Ni, Bin; Xu, Shungao; Zhu, Xueming; Xu, Huaxi; Huang, Xinxiang

    2011-02-01

    Salmonella enterica serovar Typhi z66 positive strain contains a fljBA-like operon on a linear plasmid. The operon contains the gene fljB:z66 which encodes the z66 antigen. RpoE is a sigma factor σ(E) that initiates transcription of a series of genes in Escherichia and Salmonella under environmental stresses. To investigate whether the gene fljB:z66 is regulated by RpoE (σ(E)), a rpoE deletion mutant of S. enterica serovar Typhi (ΔrpoE) was prepared in this study. The defective motility of the ΔrpoE was confirmed firstly. Transcriptional expression of flagellar genes was screened using a genomic DNA microarray. Some class-2 and most class-3 flagellar genes were downregulated in the ΔrpoE after 30 min of hyperosmotic stress. The expression of fliA and fljB:z66, a class-2 flagellar gene and a class-3 flagellar gene, obviously decreased; however, expression of the class-1 flagellar genes flhDC did not change obviously in the ΔrpoE compared to the wild-type strain in the same conditions. Results of quantitative real-time PCR (qRT-PCR) showed that the expression levels of fliA and fljB:z66 in the ΔrpoE after 30 min of hyperosmotic stress decreased about five and eightfold, respectively, compared to the wild-type strain. Similar results were observed at 120 min of hyperosmotic stress. Western blotting and qRT-PCR analysis showed that expression of fliA and fljB:z66 was significantly increased after supplemental expression of rpoE with a recombinant plasmid pBADrpoE in the ΔrpoE strain. These results demonstrated that RpoE promoted the expression of class-3 flagellar genes and it might be performed by initiating the expression of fliA in S. enterica serovar Typhi under hyperosmotic stress. PMID:20717675

  13. Detection and Molecular Characterization of Salmonella enterica Serovar Eppendorf Circulating in Chicken Farms in Tunisia.

    PubMed

    Ben Salem, R; Abbassi, M S; García, V; García-Fierro, R; Njoud, C; Messadi, L; Rodicio, M R

    2016-06-01

    Salmonella enterica subsp. enterica serovar Eppendorf, with antigenic formula 1,4,12,[27]:d:1,5, is an infrequent serovar. However, 14% (20 of 142) of the isolates recovered during June-July 2012 in chicken farms in Tunisia belonged to S. Eppendorf. These isolates were analysed for resistance and virulence profiles. None of them were susceptible to all antimicrobials tested, while 70%, 60%, 50%, 50%, 20% and 5% were resistant to sulphonamides (sul1, sul2 and sul3), streptomycin (aadA1-like), trimethoprim (dfrA1-like), nalidixic acid (GyrA Asp87 →Asn and not identified), gentamicin (not identified) and ampicillin (blaTEM -1-like). About 30% of the isolates showed decreased susceptibility to ciprofloxacin and carried the qnrB gene; 65% of the isolates were multidrug resistant and contained class 1 integrons with sul1 or sul3 in the 3' conserved segment. The orgA, ssaQ, mgtC, siiD and sopB virulence genes located on SPI1 to SPI5 and the fimbrial bcfC gene were present in all isolates; the sopE1 and sodC1 carried by prophages were variably detected; however, the prophage gipA gene and the spvC gene of serovar-specific virulence plasmids were absent. Altogether, ten resistance and three virulence profiles were identified. Typing of the isolates with XbaI- and BlnI-PFGE supports a close relationship, although they appear to be evolving under selective pressure probably caused by antimicrobial use in chicken husbandry. As far as we know, this is the first study investigating the molecular bases of antimicrobial drug resistance, the virulence gene content and the PFGE profiles of S. Eppendorf. The epidemiological surveillance of this serovar would be necessary to evaluate its possible impact on human health, particularly in Tunisia and other African countries where it was already reported. PMID:26537844

  14. Colonization and internalization of Salmonella enterica in tomato plants.

    PubMed

    Zheng, Jie; Allard, Sarah; Reynolds, Sara; Millner, Patricia; Arce, Gabriela; Blodgett, Robert J; Brown, Eric W

    2013-04-01

    The consumption of fresh tomatoes has been linked to numerous food-borne outbreaks involving various serovars of Salmonella enterica. Recent advances in our understanding of plant-microbe interactions have shown that human enteric pathogenic bacteria, including S. enterica, are adapted to survive in the plant environment. In this study, tomato plants (Solanum lycopersicum cv. Micro-Tom) grown in sandy loam soil from Virginia's eastern shore (VES) were inoculated with S. enterica serovars to evaluate plausible internalization routes and to determine if there is any niche fitness for certain serovars. Both infested soil and contaminated blossoms can lead to low internal levels of fruit contamination with Salmonella. Salmonella serovars demonstrated a great ability to survive in environments under tomato cultivation, not only in soil but also on different parts of the tomato plant. Of the five serovars investigated, Salmonella enterica serovars Newport and Javiana were dominant in sandy loam soil, while Salmonella enterica serovars Montevideo and Newport were more prevalent on leaves and blossoms. It was also observed that Salmonella enterica serovar Typhimurium had a poor rate of survival in all the plant parts examined here, suggesting that postharvest contamination routes are more likely in S. Typhimurium contamination of tomato fruit. Conversely, S. Newport was the most prevalent serovar recovered in both the tomato rhizosphere and phyllosphere. Plants that were recently transplanted (within 3 days) had an increase in observable internalized bacteria, suggesting that plants were more susceptible to internalization right after transplant. These findings suggest that the particular Salmonella serovar and the growth stage of the plant were important factors for internalization through the root system. PMID:23377940

  15. Colonization and Internalization of Salmonella enterica in Tomato Plants

    PubMed Central

    Allard, Sarah; Reynolds, Sara; Millner, Patricia; Arce, Gabriela; Blodgett, Robert J.; Brown, Eric W.

    2013-01-01

    The consumption of fresh tomatoes has been linked to numerous food-borne outbreaks involving various serovars of Salmonella enterica. Recent advances in our understanding of plant-microbe interactions have shown that human enteric pathogenic bacteria, including S. enterica, are adapted to survive in the plant environment. In this study, tomato plants (Solanum lycopersicum cv. Micro-Tom) grown in sandy loam soil from Virginia's eastern shore (VES) were inoculated with S. enterica serovars to evaluate plausible internalization routes and to determine if there is any niche fitness for certain serovars. Both infested soil and contaminated blossoms can lead to low internal levels of fruit contamination with Salmonella. Salmonella serovars demonstrated a great ability to survive in environments under tomato cultivation, not only in soil but also on different parts of the tomato plant. Of the five serovars investigated, Salmonella enterica serovars Newport and Javiana were dominant in sandy loam soil, while Salmonella enterica serovars Montevideo and Newport were more prevalent on leaves and blossoms. It was also observed that Salmonella enterica serovar Typhimurium had a poor rate of survival in all the plant parts examined here, suggesting that postharvest contamination routes are more likely in S. Typhimurium contamination of tomato fruit. Conversely, S. Newport was the most prevalent serovar recovered in both the tomato rhizosphere and phyllosphere. Plants that were recently transplanted (within 3 days) had an increase in observable internalized bacteria, suggesting that plants were more susceptible to internalization right after transplant. These findings suggest that the particular Salmonella serovar and the growth stage of the plant were important factors for internalization through the root system. PMID:23377940

  16. Prevalence and characterization of multi-drug resistant Salmonella Enterica serovar Gallinarum biovar Pullorum and Gallinarum from chicken

    PubMed Central

    Parvej, Md. Shafiullah; Nazir, K. H. M. Nazmul Hussain; Rahman, M. Bahanur; Jahan, Mueena; Khan, Mohammad Ferdousur Rahman; Rahman, Marzia

    2016-01-01

    Aim: Salmonella is an important zoonotic pathogen responsible for animal and human diseases. The aim of the present study was to determine the prevalence and stereotyping of Salmonella isolates isolated from apparently healthy poultry. Furthermore, the clonal relatedness among the isolated Salmonella serovars was assessed. Materials and Methods: A total of 150 cloacal swab samples from apparently healthy chickens were collected, and were subjected for the isolation and identification of associated Salmonella organisms. The isolated colonies were identified and characterized on the basis of morphology, cultural characters, biochemical tests, slide agglutination test, polymerase chain reaction, and pulsed-field gel electrophoresis (PFGE). Antibiotic sensitivity patterns were also investigated using commonly used antibiotics. Results: Of the 150 samples, 11 (7.33%) produced characteristics pink colony with black center on XLD agar medium, and all were culturally and biochemically confirmed to be Salmonella. All possessed serovar-specific gene SpeF and reacted uniformly with group D antisera, suggesting that all of the isolates were Salmonella Enterica serovar Gallinarum, biovar Pullorum and/or Gallinarum. Antimicrobial susceptibility testing revealed that 54.54% of the isolated Salmonella Enterica serovars were highly sensitive to ciprofloxacin, whereas the 81.81% isolates were resistant to amoxycillin, doxycycline, kanamycin, gentamycin, and tetracycline. Pulsed-field gel electrophoresis of the XbaI-digested genomic DNA exhibited identical banding patterns, suggesting that the multidrug resistant Salmonella Enterica serovars occurring in commercial layers are highly clonal in Bangladesh. Conclusion: The present study was conducted to find out the prevalence of poultry Salmonella in layer chicken and to find out the clonal relationship among them. The data in this study suggest the prevalence of Salmonella Enterica, which is multidrug resistant and highly clonal for

  17. Analysis and construction of pathogenicity island regulatory pathways in Salmonella enterica serovar Typhi.

    PubMed

    Ong, Su Yean; Ng, Fui Ling; Badai, Siti Suriawati; Yuryev, Anton; Alam, Maqsudul

    2010-01-01

    Signal transduction through protein-protein interactions and protein modifications are the main mechanisms controlling many biological processes. Here we described the implementation of MedScan information extraction technology and Pathway Studio software (Ariadne Genomics Inc.) to create a Salmonella specific molecular interaction database. Using the database, we have constructed several signal transduction pathways in Salmonella enterica serovar Typhi which causes Typhoid Fever, a major health threat especially in developing countries. S. Typhi has several pathogenicity islands that control rapid switching between different phenotypes including adhesion and colonization, invasion, intracellular survival, proliferation, and biofilm formation in response to environmental changes. Understanding of the detailed mechanism for S. Typhi survival in host cells is necessary for development of efficient detection and treatment of this pathogen. The constructed pathways were validated using publically available gene expression microarray data for Salmonella. PMID:20861532

  18. First Case of Lung Abscess due to Salmonella enterica Serovar Abony in an Immunocompetent Adult Patient.

    PubMed

    Pitiriga, Vassiliki; Dendrinos, John; Nikitiadis, Emanuel; Vrioni, Georgia; Tsakris, Athanassios

    2016-01-01

    In healthy individuals, nontyphoidal Salmonella species predominantly cause a self-limited form of gastroenteritis, while they infrequently invade or cause fatal disease. Extraintestinal manifestations of nontyphoidal Salmonella infections are not common and mainly occur among individuals with specific risk factors; among them, focal lung infection is a rare complication caused by nontyphoidal Salmonella strains typically occurring in immunocompromised patients with prior lung disease. We describe the first case of a localized lung abscess formation in an immunocompetent healthy female adult due to Salmonella enterica serovar Abony. The patient underwent lobectomy and was discharged after full clinical recovery. This case report highlights nontyphoidal Salmonellae infections as a potential causative agent of pleuropulmonary infections even in immunocompetent healthy adults. PMID:27429814

  19. Microarray-Based Detection of Salmonella enterica Serovar Enteritidis Genes Involved in Chicken Reproductive Tract Colonization

    PubMed Central

    Raspoet, R.; Appia-Ayme, C.; Shearer, N.; Martel, A.; Pasmans, F.; Haesebrouck, F.; Ducatelle, R.; Thompson, A.

    2014-01-01

    Salmonella enterica serovar Enteritidis has developed the potential to contaminate table eggs internally, by colonization of the chicken reproductive tract and internalization in the forming egg. The serotype Enteritidis has developed mechanisms to colonize the chicken oviduct more successfully than other serotypes. Until now, the strategies exploited by Salmonella Enteritidis to do so have remained largely unknown. For that reason, a microarray-based transposon library screen was used to identify genes that are essential for the persistence of Salmonella Enteritidis inside primary chicken oviduct gland cells in vitro and inside the reproductive tract in vivo. A total of 81 genes with a potential role in persistence in both the oviduct cells and the oviduct tissue were identified. Major groups of importance include the Salmonella pathogenicity islands 1 and 2, genes involved in stress responses, cell wall, and lipopolysaccharide structure, and the region-of-difference genomic islands 9, 21, and 40. PMID:25281378

  20. First Case of Lung Abscess due to Salmonella enterica Serovar Abony in an Immunocompetent Adult Patient

    PubMed Central

    Dendrinos, John; Nikitiadis, Emanuel; Vrioni, Georgia; Tsakris, Athanassios

    2016-01-01

    In healthy individuals, nontyphoidal Salmonella species predominantly cause a self-limited form of gastroenteritis, while they infrequently invade or cause fatal disease. Extraintestinal manifestations of nontyphoidal Salmonella infections are not common and mainly occur among individuals with specific risk factors; among them, focal lung infection is a rare complication caused by nontyphoidal Salmonella strains typically occurring in immunocompromised patients with prior lung disease. We describe the first case of a localized lung abscess formation in an immunocompetent healthy female adult due to Salmonella enterica serovar Abony. The patient underwent lobectomy and was discharged after full clinical recovery. This case report highlights nontyphoidal Salmonellae infections as a potential causative agent of pleuropulmonary infections even in immunocompetent healthy adults. PMID:27429814

  1. Colonization of internal organs by Salmonella serovars Heidelberg and Typhimurium in experimentally infected laying hens housed in enriched colony cages at different stocking densities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contaminated eggs produced by infected commercial laying flocks are often implicated as sources of human infections with Salmonella Enteritidis, but Salmonella serovars Heidelberg and Typhimurium have also been significantly associated with egg-transmitted illness. Contamination of the edible conten...

  2. Proteome of Salmonella Enterica SerotypeTyphimurium Grown in a Low Mg2+/pH Medium

    SciTech Connect

    Shi, Liang; Ansong, Charles; Smallwood, Heather S.; Rommereim, Leah M.; McDermott, Jason E.; Brewer, Heather M.; Norbeck, Angela D.; Taylor, Ronald C.; Gustin, Jean K.; Heffron, Fred; Smith, Richard D.; Adkins, Joshua N.

    2009-09-01

    The facultative intracellular pathogen Salmonella enterica serovar Typhimurium (STM) must replicate within host macrophages in order to establish systemic infection in susceptible mice. In an effort to identify new STM proteins that help the bacterium colonize macrophages, we have cultured STM cells with a low pH/low magnesium medium (MgM) under two different conditions termed MgM-Shock and MgM-Dilution and investigated the impacts of these culturing conditions on the STM proteome by using liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics. LC-MS/MS results showed that alteration of culturing conditions affected a group of STM proteins differently. Compared to MgM-Shock, MgM-Dilution induced more proteins of the Salmonella-pathogenecity island 2-type III secretion system (SPI2-T3SS). The abundances of the proteins used for cobalamin biosynthesis increased under MgM-Shock condition but decreased under MgM-Dilution condition, while those proteins used for thiamine or biotin biosynthesis were not affected under the former condition but increased under the latter condition. Western-blot (WB) analysis confirmed the LC-MS/MS results. Because cobalamin, thiamine and biotin play different roles in STM metabolism, differential induction of the proteins involved in their biosyntheses suggests that the metabolic states of STM cells under these conditions differ considerably. WB analysis also showed that the abundances of SPI2-T3SS proteins SsaQ and SseE and biotin biosynthesis proteins BioB and BioD increased after STM infection of RAW 264.7 macrophages. Deletion of the gene encoding BioB reduced the ability of STM to replicate inside the macrophages, demonstrating for the first time the involvement of a biotin synthesis protein in STM colonization of macrophages.

  3. Genomic comparison of the closely-related Salmonella enterica serovars enteritidis, dublin and gallinarum

    SciTech Connect

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; Hanna, Leigh Farris; Schifferli, Dieter M.; Maloy, Stanley; Dinsdale, Elizabeth A.; Edwards, Robert A.; Cloeckaert, Axel

    2015-06-03

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.

  4. Highly Drug-Resistant Salmonella enterica Serovar Indiana Clinical Isolates Recovered from Broilers and Poultry Workers with Diarrhea in China.

    PubMed

    Gong, Jiansen; Wang, Chengming; Shi, Shourong; Bao, Hongduo; Zhu, Chunhong; Kelly, Patrick; Zhuang, Linlin; Lu, Guangwu; Dou, Xinhong; Wang, Ran; Xu, Bu; Zou, Jianmin

    2016-03-01

    Highly drug-resistant Salmonella enterica serovar Indiana became the most common serovar in broilers with diarrhea in China over the course of this study (15% in 2010 to 70% in 2014). While most S. Indiana isolates (87%, 384/440) were resistant to 13 to 16 of the 16 antibiotics tested, 89% of non-S. Indiana isolates (528/595) were resistant to 0 to 6 antibiotics. Class 1 integrons and IncHI2-type plasmids were detected in all S. Indiana isolates, but only in 39% and 1% of non-S. Indiana isolates. PMID:26824960

  5. Antimicrobial Drug Resistance and Molecular Typing of Salmonella enterica Serovar Rissen from Different Sources.

    PubMed

    García-Fierro, Raquel; Montero, Ignacio; Bances, Margarita; González-Hevia, Maria Ángeles; Rodicio, María Rosario

    2016-04-01

    Salmonella enterica serovar Rissen is one of the most common serovars found in pigs and pork products in different countries, including Spain. However, information on the molecular bases of antimicrobial drug resistance and the population structure of Salmonella Rissen from different sources in Spain is limited. The present study focused on 84 isolates collected in Spain from pig and beef carcasses, foods and clinical samples associated with sporadic cases of gastroenteritis, and one outbreak. The majority of the isolates were resistant to tetracycline (73.8%), mainly conferred by tet(A). Resistances to streptomycin (aadA1-like, aadA2, and strAB), sulfonamides (sul1, sul2, and sul3), trimethoprim (dfrA1-like and dfrA12), ampicillin (blaTEM-1-like), and chloramphenicol (cmlA1-like) were also detected, with frequencies ranging from 12% to 20.2%. Most of the identified genes were carried by integrons, including three class 1 integrons of the sul1 type, a class 1 integron of the sul3 type, and the class 2 integron of Tn7. Two sul1 integrons, the sul3 integron, and the class 2 integron are first reported in Salmonella Rissen. Typing of the isolates with XbaI pulsed-field gel electrophoresis detected a major clone, which was circulating in humans and animals during the past decade, and was responsible for the outbreak. The obtained results are relevant for food safety and public health. PMID:26295933

  6. Lack of efflux mediated quinolone resistance in Salmonella enterica serovars Typhi and Paratyphi A.

    PubMed

    Baucheron, Sylvie; Monchaux, Isabelle; Le Hello, Simon; Weill, François-Xavier; Cloeckaert, Axel

    2014-01-01

    Salmonella enterica serovars Typhi and Paratyphi A isolates from human patients in France displaying different levels of resistance to quinolones or fluoroquinolones were studied for resistance mechanisms to these antimicrobial agents. All resistant isolates carried either single or multiple target gene mutations (i.e., in gyrA, gyrB, or parC) correlating with the resistance levels observed. Active efflux, through upregulation of multipartite efflux systems, has also been previously reported as contributing mechanism for other serovars. Therefore, we investigated also the occurrence of non-target gene mutations in regulatory regions affecting efflux pump expression. However, no mutation was detected in these regions in both Typhi and Paratyphi isolates of this study. Besides, no overexpression of the major efflux systems was observed for these isolates. Nevertheless, a large deletion of 2334 bp was identified in the acrS-acrE region of all S. Typhi strains but which did not affect the resistance phenotype. As being specific to S. Typhi, this deletion could be used for specific molecular detection purposes. In conclusion, the different levels of quinolone or FQ resistance in both S. Typhi and S. Paratyphi A seem to rely only on target modifications. PMID:24478769

  7. Regulation and production of Tcf, a cable-like fimbriae from Salmonella enterica serovar Typhi.

    PubMed

    Leclerc, Jean-Mathieu; Quevillon, Eve-Lyne; Houde, Yoan; Paranjape, Kiran; Dozois, Charles M; Daigle, France

    2016-05-01

    tcf (Typhi colonization factor) is one of the 12 putative chaperone/usher fimbrial clusters present in the Salmonella enterica serovar Typhi genome. We investigated the production, expression and regulation of tcf as well as its role during interaction with human cells. The tcf gene cluster was cloned and induced in Escherichia coli and S. Typhi, and the production of intertwined fibres similar to the Cbl (cable) pili of Burkholderia cepacia was observed on the bacterial surface by electron microscopy. In S. Typhi, tcf was expressed more after growth in M63 minimal medium than in standard Luria-Bertani medium. Analysis of the promoter region identified putative binding sites for the global regulators RcsB, ArgR and Fur. The expression of tcf was measured in isogenic strains lacking these global regulators. Under the conditions tested, the results showed that tcf expression was higher in the fur mutant and was regulated by iron concentration. Fur may regulate these fimbriae indirectly via the small RNAs RyhB1 and RyhB2. An isogenic mutant harbouring a deletion of the tcf cluster did not demonstrate any defect in adhesion or invasion of human epithelial cells, or in phagocytosis or survival in macrophages, when compared to the WT serovar Typhi strain. However, the tcf cluster contributed to adherence to human epithelial cells when introduced into E. coli. Thus, tcf genes encode functional fimbriae that can act as an adhesin and may contribute to colonization during typhoid fever. PMID:26944792

  8. Experimental infection of chickens by a flagellated motile strain of Salmonella enterica serovar Gallinarum biovar Gallinarum.

    PubMed

    Lopes, P D; Freitas Neto, O C; Batista, D F A; Denadai, J; Alarcon, M F F; Almeida, A M; Vasconcelos, R O; Setta, A; Barrow, P A; Berchieri, A

    2016-08-01

    Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (SG) causes fowl typhoid (FT), a septicaemic disease which can result in high mortality in poultry flocks. The absence of flagella in SG is thought to favour systemic invasion, since bacterial recognition via Toll-like receptor (TLR)-5 does not take place during the early stages of FT. In the present study, chicks susceptible to FT were inoculated with a wild type SG (SG) or its flagellated motile derivative (SG Fla(+)). In experiment 1, mortality and clinical signs were assessed, whereas in experiment 2, gross pathology, histopathology, systemic invasion and immune responses were evaluated. SG Fla(+) infection resulted in later development of clinical signs, lower mortality, lower bacterial numbers in the liver and spleen, and less severe pathological changes compared to SG. The CD8(+) T lymphocyte population was higher in the livers of chicks infected with SG at 4 days post-inoculation (dpi). Chicks infected with SG had increased expression of interleukin (IL)-6 mRNA in the caecal tonsil at 1 dpi and increased expression of IL-18 mRNA in the spleen at 4 dpi. In contrast, the CD4(+) T lymphocyte population was higher at 6 dpi in the livers of birds infected with SG Fla(+). Therefore, flagella appeared to modulate the chicken immune response towards a CD4(+) T profile, resulting in more efficient bacterial clearance from systemic sites and milder infection. PMID:27387725

  9. Temperature-Sensitive Salmonella enterica Serovar Enteritidis PT13a Expressing Essential Proteins of Psychrophilic Bacteria

    PubMed Central

    Duplantis, Barry N.; Puckett, Stephanie M.; Rosey, Everett L.; Ameiss, Keith A.; Hartman, Angela D.; Pearce, Stephanie C.

    2015-01-01

    Synthetic genes based on deduced amino acid sequences of the NAD-dependent DNA ligase (ligA) and CTP synthetase (pyrG) of psychrophilic bacteria were substituted for their native homologues in the genome of Salmonella enterica serovar Enteritidis phage type 13a (PT13a). The resulting strains were rendered temperature sensitive (TS) and did not revert to temperature resistance at a detectable level. At permissive temperatures, TS strains grew like the parental strain in broth medium and in macrophage-like cells, but their growth was slowed or stopped when they were shifted to a restrictive temperature. When injected into BALB/c mice at the base of the tail, representing a cool site of the body, the strains with restrictive temperatures of 37, 38.5, and 39°C persisted for less than 1 day, 4 to 7 days, and 20 to 28 days, respectively. The wild-type strain persisted at the site of inoculation for at least 28 days. The wild-type strain, but not the TS strains, was also found in spleen-plus-liver homogenates within 1 day of inoculation of the tail and was detectable in these organs for at least 28 days. Intramuscular vaccination of White Leghorn chickens with the PT13a strain carrying the psychrophilic pyrG gene provided some protection against colonization of the reproductive tract and induced an anti-S. enterica antibody response. PMID:26187965

  10. Transcriptional profile of Salmonella enterica subsp. enterica serovar Weltevreden during alfalfa sprout colonization

    PubMed Central

    Brankatschk, Kerstin; Kamber, Tim; Pothier, Joël F; Duffy, Brion; Smits, Theo H M

    2014-01-01

    Sprouted seeds represent a great risk for infection by human enteric pathogens because of favourable growth conditions for pathogens during their germination. The aim of this study was to identify mechanisms of interactions of Salmonella enterica subsp. enterica Weltevreden with alfalfa sprouts. RNA-seq analysis of S. Weltevreden grown with sprouts in comparison with M9-glucose medium showed that among a total of 4158 annotated coding sequences, 177 genes (4.3%) and 345 genes (8.3%) were transcribed at higher levels with sprouts and in minimal medium respectively. Genes that were higher transcribed with sprouts are coding for proteins involved in mechanisms known to be important for attachment, motility and biofilm formation. Besides gene expression required for phenotypic adaption, genes involved in sulphate acquisition were higher transcribed, suggesting that the surface on alfalfa sprouts may be poor in sulphate. Genes encoding structural and effector proteins of Salmonella pathogenicity island 2, involved in survival within macrophages during infection of animal tissue, were higher transcribed with sprouts possibly as a response to environmental conditions. This study provides insight on additional mechanisms that may be important for pathogen interactions with sprouts. PMID:24308841

  11. Genomic Evidence Reveals Numerous Salmonella enterica Serovar Newport Reintroduction Events in Suwannee Watershed Irrigation Ponds

    PubMed Central

    Jackson, Scott A.; Gangiredla, Jayanthi; Wang, Weimin; Liu, Huanli; Tall, Ben D.; Beaubrun, Junia Jean-Gilles; Jay-Russell, Michele; Vellidis, George; Elkins, Christopher A.

    2015-01-01

    Our previous work indicated a predominance (56.8%) of Salmonella enterica serovar Newport among isolates recovered from irrigation ponds used in produce farms over a 2-year period (B. Li et al., Appl Environ Microbiol 80:6355–6365, http://dx.doi.org/10.1128/AEM.02063-14). This observation provided a valuable set of metrics to explore an underaddressed issue of environmental survival of Salmonella by DNA microarray. Microarray analysis correctly identified all the isolates (n = 53) and differentiated the S. Newport isolates into two phylogenetic lineages (S. Newport II and S. Newport III). Serovar distribution analysis showed no instances where the same serovar was recovered from a pond for more than a month. Furthermore, during the study, numerous isolates with an indistinguishable genotype were recovered from different ponds as far as 180 km apart for time intervals as long as 2 years. Although isolates within either lineage were phylogenetically related as determined by microarray analysis, subtle genotypic differences were detected within the lineages, suggesting that isolates in either lineage could have come from several unique hosts. For example, strains in four different subgroups (A, B, C, and D) possessed an indistinguishable genotype within their subgroups as measured by gene differences, suggesting that strains in each subgroup shared a common host. Based on this comparative genomic evidence and the spatial and temporal factors, we speculated that the presence of Salmonella in the ponds was likely due to numerous punctuated reintroduction events associated with several different but common hosts in the environment. These findings may have implications for the development of strategies for efficient and safe irrigation to minimize the risk of Salmonella outbreaks associated with fresh produce. PMID:26386063

  12. Molecular Characterization of Salmonella enterica Serovar Aberdeen Negative for H2S Production in China.

    PubMed

    Wu, Fuli; Xu, Xuebin; Xie, Jing; Yi, Shengjie; Wang, Jian; Yang, Xiaoxia; Yang, Chaojie; Liang, Beibei; Ma, Qiuxia; Li, Hao; Song, Hongbin; Qiu, Shaofu

    2016-01-01

    Salmonella enterica infections continue to be a significant burden on public health worldwide. The ability of S. enterica to produce hydrogen sulfide (H2S) is an important phenotypic characteristic used to screen and identify Salmonella with selective medium; however, H2S-negative Salmonella have recently emerged. In this study, the H2S phenotype of Salmonella isolates was confirmed, and the selected isolates were subjected to antimicrobial susceptibility testing and molecular identification by multilocus sequence typing, pulsed-field gel electrophoresis, and clustered regularly interspaced short palindromic repeat (CRISPR) analysis. The phs genetic operon was also analyzed. A total of 160 S. enterica serovar Aberdeen isolates were detected between 2005 and 2013 in China. Of them, seven non-H2S-producing isolates were detected. Notably, four samples yielded four pairs of isolates with different H2S phenotypes, simultaneously. The data demonstrated that H2S-negative isolates were genetically closely related to H2S-positive isolates. Three new spacers (Abe1, Abe2, and Abe3) were identified in CRISPR locus 1 in four pairs of isolates with different H2S phenotypes from the same samples. Sequence analysis revealed a new nonsense mutation at position 208 in the phsA gene of all non-H2S-producing isolates. Additionally, we describe a new screening procedure to avoid H2S-negative Salmonella, which would normally be overlooked during laboratory and hospital screening. The prevalence of this pathogen may be underestimated; therefore, it is important to focus on improving surveillance of this organism to control its spread. PMID:27552230

  13. Molecular Characterization of Salmonella enterica Serovar Aberdeen Negative for H2S Production in China

    PubMed Central

    Yi, Shengjie; Wang, Jian; Yang, Xiaoxia; Yang, Chaojie; Liang, Beibei; Ma, Qiuxia; Li, Hao; Song, Hongbin; Qiu, Shaofu

    2016-01-01

    Salmonella enterica infections continue to be a significant burden on public health worldwide. The ability of S. enterica to produce hydrogen sulfide (H2S) is an important phenotypic characteristic used to screen and identify Salmonella with selective medium; however, H2S-negative Salmonella have recently emerged. In this study, the H2S phenotype of Salmonella isolates was confirmed, and the selected isolates were subjected to antimicrobial susceptibility testing and molecular identification by multilocus sequence typing, pulsed-field gel electrophoresis, and clustered regularly interspaced short palindromic repeat (CRISPR) analysis. The phs genetic operon was also analyzed. A total of 160 S. enterica serovar Aberdeen isolates were detected between 2005 and 2013 in China. Of them, seven non-H2S-producing isolates were detected. Notably, four samples yielded four pairs of isolates with different H2S phenotypes, simultaneously. The data demonstrated that H2S-negative isolates were genetically closely related to H2S-positive isolates. Three new spacers (Abe1, Abe2, and Abe3) were identified in CRISPR locus 1 in four pairs of isolates with different H2S phenotypes from the same samples. Sequence analysis revealed a new nonsense mutation at position 208 in the phsA gene of all non-H2S-producing isolates. Additionally, we describe a new screening procedure to avoid H2S-negative Salmonella, which would normally be overlooked during laboratory and hospital screening. The prevalence of this pathogen may be underestimated; therefore, it is important to focus on improving surveillance of this organism to control its spread. PMID:27552230