Comparison of Salmonella enterica subspecies enterica serovar Typhimurium isolates from dairy cattle and humans using in vitro assays of virulence

Coordination of the expression of Salmonella enterica invasion genes on Salmonella pathogenicity island 1 (SPI1) depends on a complex circuit involving several regulators that converge on expression of the hilA gene, which encodes a transcriptional activator (HilA) that modulates expression of the SPI1 virulence genes. Two of the global regulators that influence hilA expression are the nucleoid-associated proteins Hha and H-NS. They interact and form a complex that modulates gene expression. A chromosomal transcriptional fusion was constructed to assess the effects of these modulators on hilA transcription under several environmental conditions as well as at different stages of growth. The results obtained showed that these proteins play a role in silencing hilA expression at both low temperature and low osmolarity, irrespective of the growth phase. H-NS accounts for the main repressor activity. At high temperature and osmolarity, H-NS-mediated silencing completely ceases when cells enter the stationary phase, and hilA expression is induced. Mutants lacking IHF did not induce hilA in cells entering the stationary phase, and this lack of induction was dependent on the presence of H-NS. Band-shift assays and in vitro transcription data showed that for hilA induction under certain growth conditions, IHF is required to alleviate H-NS-mediated silencing.

Download Full-text

Caveolin-1-Deficient Mice Show Defects in Innate Immunity and Inflammatory Immune Response during Salmonella enterica Serovar Typhimurium Infection

Infection and Immunity ◽

10.1128/iai.00949-06 ◽

2006 ◽

Vol 74 (12) ◽

pp. 6665-6674 ◽

Cited By ~ 57

Author(s):

Freddy A. Medina ◽

Cecilia J. de Almeida ◽

Elliott Dew ◽

Jiangwei Li ◽

Gloria Bonuccelli ◽

...

Keyword(s):

Nitric Oxide ◽

Salmonella Enterica ◽

Inflammatory Responses ◽

Systemic Infection ◽

Bacterial Invasion ◽

Chemokine Production ◽

Caveolin 1 ◽

Serovar Typhimurium ◽

Deficient Mice

ABSTRACT A number of studies have shown an association of pathogens with caveolae. To this date, however, there are no studies showing a role for caveolin-1 in modulating immune responses against pathogens. Interestingly, expression of caveolin-1 has been shown to occur in a regulated manner in immune cells in response to lipopolysaccharide (LPS). Here, we sought to determine the role of caveolin-1 (Cav-1) expression in Salmonella pathogenesis. Cav-1−/− mice displayed a significant decrease in survival when challenged with Salmonella enterica serovar Typhimurium. Spleen and tissue burdens were significantly higher in Cav-1−/− mice. However, infection of Cav-1−/− macrophages with serovar Typhimurium did not result in differences in bacterial invasion. In addition, Cav-1−/− mice displayed increased production of inflammatory cytokines, chemokines, and nitric oxide. Regardless of this, Cav-1−/− mice were unable to control the systemic infection of Salmonella. The increased chemokine production in Cav-1−/− mice resulted in greater infiltration of neutrophils into granulomas but did not alter the number of granulomas present. This was accompanied by increased necrosis in the liver. However, Cav-1−/− macrophages displayed increased inflammatory responses and increased nitric oxide production in vitro in response to Salmonella LPS. These results show that caveolin-1 plays a key role in regulating anti-inflammatory responses in macrophages. Taken together, these data suggest that the increased production of toxic mediators from macrophages lacking caveolin-1 is likely to be responsible for the marked susceptibility of caveolin-1-deficient mice to S. enterica serovar Typhimurium.

Download Full-text

Terminal Deoxynucleotidyl Transferase Is Not Required for Antibody Response to Polysaccharide Vaccines againstStreptococcus pneumoniaeandSalmonella entericaSerovar Typhi

Infection and Immunity ◽

10.1128/iai.00211-18 ◽

2018 ◽

Vol 86 (9) ◽

Author(s):

Vivek Belde ◽

Matthew P. Cravens ◽

Dania Gulandijany ◽

Justin A. Walker ◽

Isabel Palomo-Caturla ◽

...

Keyword(s):

Antibody Response ◽

B Cell ◽

Salmonella Enterica ◽

Passive Immunization ◽

Terminal Deoxynucleotidyl Transferase ◽

Human Infants ◽

Content Type ◽

Serovar Typhimurium

ABSTRACTB cell antigen receptor (BCR) diversity increases by several orders of magnitude due to the action of terminal deoxynucleotidyl transferase (TdT) during V(D)J recombination. Unlike adults, infants have limited BCR diversity, in part due to reduced expression of TdT. Since human infants and young mice respond poorly to polysaccharide vaccines, such as the pneumococcal polysaccharide vaccine Pneumovax23 and Vi polysaccharide (ViPS) ofSalmonella entericaserovar Typhi, we tested the contribution of TdT-mediated BCR diversity in response to these vaccines. We found that TdT+/−and TdT−/−mice generated comparable antibody responses to Pneumovax23 and survivedStreptococcus pneumoniaechallenge. Moreover, passive immunization of B cell-deficient mice with serum from Pneumovax23-immunized TdT+/−or TdT−/−mice conferred protection. TdT+/−and TdT−/−mice generated comparable levels of anti-ViPS antibodies and antibody-dependent, complement-mediated bactericidal activity againstS. Typhiin vitro. To test the protective immunity conferred by ViPS immunizationin vivo, TdT+/−and TdT−/−mice were challenged with a chimericSalmonella entericaserovar Typhimurium strain expressing ViPS, since mice are nonpermissive hosts forS. Typhi infection. Compared to their unimmunized counterparts, immunized TdT+/−and TdT−/−mice challenged with ViPS-expressingS. Typhimurium exhibited a significant reduction in the bacterial burden and liver pathology. These data suggest that the impaired antibody response to the Pneumovax23 and ViPS vaccines in the young is not due to limited TdT-mediated BCR diversification.

Download Full-text

Attenuation of Salmonella enterica Serovar Typhimurium by Altering Biological Functions of Murein Lipoprotein and Lipopolysaccharide

Infection and Immunity ◽

10.1128/iai.73.12.8433-8436.2005 ◽

2005 ◽

Vol 73 (12) ◽

pp. 8433-8436 ◽

Cited By ~ 8

Author(s):

A. A. Fadl ◽

J. Sha ◽

G. R. Klimpel ◽

J. P. Olano ◽

C. L. Galindo ◽

...

Keyword(s):

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Biological Functions ◽

Double Knockout ◽

In Vivo Models ◽

Background Strain ◽

Knockout Mutants ◽

Serovar Typhimurium

ABSTRACT We constructed Salmonella enterica serovar Typhimurium double-knockout mutants in which either the lipoprotein A (lppA) or the lipoprotein B (lppB) gene was deleted from an msbB-negative background strain by marker exchange mutagenesis. These mutants were highly attenuated when tested with in vitro and in vivo models of Salmonella pathogenesis.

Download Full-text

Differences in Enzymatic Properties Allow SodCI but Not SodCII To Contribute to Virulence in Salmonella enterica Serovar Typhimurium Strain 14028

Journal of Bacteriology ◽

10.1128/jb.186.16.5230-5238.2004 ◽

2004 ◽

Vol 186 (16) ◽

pp. 5230-5238 ◽

Cited By ~ 40

Author(s):

Radha Krishnakumar ◽

Maureen Craig ◽

James A. Imlay ◽

James M. Slauch

Keyword(s):

Salmonella Enterica ◽

Osmotic Shock ◽

Acid Resistance ◽

Noncovalent Interaction ◽

Open Reading Frames ◽

Striking Difference ◽

Significant Difference ◽

Serovar Typhimurium

ABSTRACT Salmonella enterica serovar Typhimurium produces two Cu/Zn cofactored periplasmic superoxide dismutases, SodCI and SodCII. While mutations in sodCI attenuate virulence eightfold, loss of SodCII does not confer a virulence phenotype, nor does it enhance the defect observed in a sodCI background. Despite this in vivo phenotype, SodCI and SodCII are expressed at similar levels in vitro during the stationary phase of growth. By exchanging the open reading frames of sodCI and sodCII, we found that SodCI contributes to virulence when placed under the control of the sodCII promoter. In contrast, SodCII does not contribute to virulence even when expressed from the sodCI promoter. Thus, the disparity in virulence phenotypes is due primarily to some physical difference between the two enzymes. In an attempt to identify the unique property of SodCI, we have tested factors that might affect enzyme activity inside a phagosome. We found no significant difference between SodCI and SodCII in their resistance to acid, resistance to hydrogen peroxide, or ability to obtain copper in a copper-limiting environment. Both enzymes are synthesized as apoenzymes in the absence of copper and can be fully remetallated when copper is added. The one striking difference that we noted is that, whereas SodCII is released normally by an osmotic shock, SodCI is “tethered” within the periplasm by an apparently noncovalent interaction. We propose that this novel property of SodCI is crucial to its ability to contribute to virulence in serovar Typhimurium.

Download Full-text

Novel Salmonella enterica Serovar Typhimurium Protein That Is Indispensable for Virulence and Intracellular Replication

Infection and Immunity ◽

10.1128/iai.69.12.7413-7418.2001 ◽

2001 ◽

Vol 69 (12) ◽

pp. 7413-7418 ◽

Cited By ~ 11

Author(s):

Tahar van der Straaten ◽

Angela van Diepen ◽

Kitty Kwappenberg ◽

Sjaak van Voorden ◽

Kees Franken ◽

...

Keyword(s):

Amino Acid ◽

Protein Function ◽

Salmonella Enterica ◽

Host Cells ◽

Wild Type ◽

Intracellular Replication ◽

Oxygen Intermediates ◽

Serovar Typhimurium

ABSTRACT Upon contact with host cells, the intracellular pathogenSalmonella 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 undescribedSalmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonellachromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 104 to 107bacteria in C3H/HeN and 101 to 104 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.

Download Full-text

In Vitro and In Vivo Assessment of Salmonella enterica Serovar Typhimurium DT104 Virulence

Infection and Immunity ◽

10.1128/iai.69.7.4673-4677.2001 ◽

2001 ◽

Vol 69 (7) ◽

pp. 4673-4677 ◽

Cited By ~ 25

Author(s):

Chris A. Allen ◽

Paula J. Fedorka-Cray ◽

Andrés Vazquez-Torres ◽

Mitsu Suyemoto ◽

Craig Altier ◽

...

Keyword(s):

Salmonella Enterica ◽

Phage Type ◽

Multidrug Resistant ◽

Peritoneal Macrophages ◽

Lethal Infection ◽

Animal Infection ◽

Serovar Typhimurium ◽

Clinical Illness

ABSTRACT Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has become a widespread cause of human and other animal infection worldwide. The severity of clinical illness inS. enterica serovar Typhimurium DT104 outbreaks has led to the suggestion that this strain possesses enhanced virulence. In the present study, in vitro and in vivo virulence-associated phenotypes of several clinical isolates of S. enterica serovar Typhimurium DT104 were examined and compared to S. entericaserovar Typhimurium ATCC 14028s. The ability of these DT104 isolates to survive within murine peritoneal macrophages, invade cultured epithelial cells, resist antimicrobial actions of reactive oxygen and nitrogen compounds, and cause lethal infection in mice were assessed. Our results failed to demonstrate that S. enterica serovar Typhimurium DT104 isolates are more virulent than S. enterica serovar Typhimurium ATCC 14028s.

Download Full-text

The absence of murine cathelicidin-related antimicrobial peptide impacts host responses enhancing Salmonella enterica serovar Typhimurium infection

Gut Pathogens ◽

10.1186/s13099-020-00386-1 ◽

2020 ◽

Vol 12 (1) ◽

Author(s):

Danisa M. Bescucci ◽

Sandra T. Clarke ◽

Catherine L. J. Brown ◽

Valerie F. Boras ◽

Tony Montina ◽

...

Keyword(s):

Antimicrobial Peptide ◽

Salmonella Enterica ◽

Systemic Infection ◽

Cell Loss ◽

Host Responses ◽

Post Inoculation ◽

Systemic Dissemination ◽

Serovar Typhimurium ◽

The Impact

Abstract Background Cathelicidins are a class of antimicrobial peptide, and the murine cathelicidin-related antimicrobial peptide (mCRAMP) has been demonstrated in vitro to impair Salmonella enterica serovar Typhimurium proliferation. However, the impact of mCRAMP on host responses and the microbiota following S. Typhimurium infection has not been determined. In this study mCRAMP−/− and mCRAMP+/+ mice (± streptomycin) were orally inoculated with S. enterica serovar Typhimurium DT104 (SA +), and impacts on the host and enteric bacterial communities were temporally evaluated. Results Higher densities of the pathogen were observed in cecal digesta and associated with mucosa in SA+/mCRAMP−/− mice that were pretreated (ST+) and not pretreated (ST−) with streptomycin at 24 h post-inoculation (hpi). Both SA+/ST+/mCRAMP−/− and SA+/ST−/mCRAMP−/− mice were more susceptible to infection exhibiting greater histopathologic changes (e.g. epithelial injury, leukocyte infiltration, goblet cell loss) at 48 hpi. Correspondingly, immune responses in SA+/ST+/mCRAMP–/− and SA+/ST−/mCRAMP–/− mice were affected (e.g. Ifnγ, Kc, Inos, Il1β, RegIIIγ). Systemic dissemination of the pathogen was characterized by metabolomics, and the liver metabolome was affected to a greater degree in SA+/ST+/mCRAMP–/− and SA+/ST−/mCRAMP–/− mice (e.g. taurine, cadaverine). Treatment-specific changes to the structure of the enteric microbiota were associated with infection and mCRAMP deficiency, with a higher abundance of Enterobacteriaceae and Veillonellaceae observed in infected null mice. The microbiota of mice that were administered the antibiotic and infected with Salmonella was dominated by Proteobacteria. Conclusion The study findings showed that the absence of mCRAMP modulated both host responses and the enteric microbiota enhancing local and systemic infection by Salmonella Typhimurium.

Download Full-text

Persistent Salmonella enterica Serovar Typhimurium Infection Induces Protease Expression During Intestinal Fibrosis

Inflammatory Bowel Diseases ◽

10.1093/ibd/izz070 ◽

2019 ◽

Vol 25 (10) ◽

pp. 1629-1643 ◽

Cited By ~ 3

Author(s):

Katrin Ehrhardt ◽

Natalie Steck ◽

Reinhild Kappelhoff ◽

Stephanie Stein ◽

Florian Rieder ◽

...

Keyword(s):

Protease Inhibitors ◽

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Salmonella Infection ◽

Intestinal Fibrosis ◽

Fibrotic Tissue ◽

Serovar Typhimurium ◽

Inflammatory Bowel ◽

Protease Expression

AbstractBackgroundIntestinal fibrosis is a common and serious complication of Crohn’s disease characterized by the accumulation of fibroblasts, deposition of extracellular matrix, and formation of scar tissue. Although many factors including cytokines and proteases contribute to the development of intestinal fibrosis, the initiating mechanisms and the complex interplay between these factors remain unclear.MethodsChronic infection of mice with Salmonella enterica serovar Typhimurium was used to induce intestinal fibrosis. A murine protease-specific CLIP-CHIP microarray analysis was employed to assess regulation of proteases and protease inhibitors. To confirm up- or downregulation during fibrosis, we performed quantitative real-time polymerase chain reaction (PCR) and immunohistochemical stainings in mouse tissue and tissue from patients with inflammatory bowel disease. In vitro infections were used to demonstrate a direct effect of bacterial infection in the regulation of proteases.ResultsMice develop severe and persistent intestinal fibrosis upon chronic infection with Salmonella enterica serovar Typhimurium, mimicking the pathology of human disease. Microarray analyses revealed 56 up- and 40 downregulated proteases and protease inhibitors in fibrotic cecal tissue. Various matrix metalloproteases, serine proteases, cysteine proteases, and protease inhibitors were regulated in the fibrotic tissue, 22 of which were confirmed by quantitative real-time PCR. Proteases demonstrated site-specific staining patterns in intestinal fibrotic tissue from mice and in tissue from human inflammatory bowel disease patients. Finally, we show in vitro that Salmonella infection directly induces protease expression in macrophages and epithelial cells but not in fibroblasts.ConclusionsIn summary, we show that chronic Salmonella infection regulates proteases and protease inhibitors during tissue fibrosis in vivo and in vitro, and therefore this model is well suited to investigating the role of proteases in intestinal fibrosis.

Download Full-text

QseC Mediates Salmonella enterica Serovar Typhimurium Virulence In Vitro and In Vivo

Infection and Immunity ◽

10.1128/iai.01038-09 ◽

2009 ◽

Vol 78 (3) ◽

pp. 914-926 ◽

Cited By ~ 102

Author(s):

Cristiano G. Moreira ◽

David Weinshenker ◽

Vanessa Sperandio

Keyword(s):

Epithelial Cells ◽

Salmonella Enterica ◽

Systemic Disease ◽

Systemic Infection ◽

Flagellar Motility ◽

Signaling System ◽

Interkingdom Signaling ◽

Serovar Typhimurium

ABSTRACT The autoinducer-3 (AI-3)/epinephrine (Epi)/norepinephrine (NE) interkingdom signaling system mediates chemical communication between bacteria and their mammalian hosts. The three signals are sensed by the QseC histidine kinase (HK) sensor. Salmonella enterica serovar Typhimurium is a pathogen that uses HKs to sense its environment and regulate virulence. Salmonella serovar Typhimurium invades epithelial cells and survives within macrophages. Invasion of epithelial cells is mediated by the type III secretion system (T3SS) encoded in Salmonella pathogenicity island 1 (SPI-1), while macrophage survival and systemic disease are mediated by the T3SS encoded in SPI-2. Here we show that QseC plays an important role in Salmonella serovar Typhimurium pathogenicity. A qseC mutant was impaired in flagellar motility, in invasion of epithelial cells, and in survival within macrophages and was attenuated for systemic infection in 129x1/SvJ mice. QseC acts globally, regulating expression of genes within SPI-1 and SPI-2 in vitro and in vivo (during infection of mice). Additionally, dopamine β-hydroxylase knockout (Dbh − / −) mice that do not produce Epi or NE showed different susceptibility to Salmonella serovar Typhimurium infection than wild-type mice. These data suggest that the AI-3/Epi/NE signaling system is a key factor during Salmonella serovar Typhimurium pathogenesis in vitro and in vivo. Elucidation of the role of this interkingdom signaling system in Salmonella serovar Typhimurium should contribute to a better understanding of the complex interplay between the pathogen and the host during infection.

Download Full-text