scholarly journals Single passage in mouse organs enhances the survival and spread of Salmonella enterica

2015 ◽  
Vol 12 (113) ◽  
pp. 20150702 ◽  
Author(s):  
Richard Dybowski ◽  
Olivier Restif ◽  
Alexandre Goupy ◽  
Duncan J. Maskell ◽  
Piero Mastroeni ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Probability Generating Function ◽  
Systemic Infection ◽  
Original Method ◽  
Wild Type ◽  
Immigration Process ◽  
Serovar Typhimurium ◽  
Intravenous Inoculation

Intravenous inoculation of Salmonella enterica serovar Typhimurium into mice is a prime experimental model of invasive salmonellosis. The use of wild-type isogenic tagged strains (WITS) in this system has revealed that bacteria undergo independent bottlenecks in the liver and spleen before establishing a systemic infection. We recently showed that those bacteria that survived the bottleneck exhibited enhanced growth when transferred to naive mice. In this study, we set out to disentangle the components of this in vivo adaptation by inoculating mice with WITS grown either in vitro or in vivo . We developed an original method to estimate the replication and killing rates of bacteria from experimental data, which involved solving the probability-generating function of a non-homogeneous birth–death–immigration process. This revealed a low initial mortality in bacteria obtained from a donor animal. Next, an analysis of WITS distributions in the livers and spleens of recipient animals indicated that in vivo -passaged bacteria started spreading between organs earlier than in vitro -grown bacteria. These results further our understanding of the influence of passage in a host on the fitness and virulence of Salmonella enterica and represent an advance in the power of investigation on the patterns and mechanisms of host–pathogen interactions.

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

2001 ◽  
Vol 69 (12) ◽  
pp. 7413-7418 ◽  
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.

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

2009 ◽  
Vol 78 (3) ◽  
pp. 914-926 ◽  
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.

scholarly journals Role of B7 Costimulatory Molecules in Mediating Systemic and Mucosal Antibody Responses to Attenuated Salmonella enterica Serovar Typhimurium and Its Cloned Antigen

2004 ◽  
Vol 72 (10) ◽  
pp. 5824-5831 ◽  
Author(s):  
Carlos A. Garcia ◽  
Michael Martin ◽  
Suzanne M. Michalek
Keyword(s):  
Salmonella Enterica ◽  
Immunoglobulin A ◽  
Costimulatory Molecules ◽  
Antibody Responses ◽  
Wild Type ◽  
Igg Antibody ◽  
Functional Roles ◽  
Serovar Typhimurium

ABSTRACT The purpose of the present study was to evaluate the ability of an attenuated Salmonella enterica serovar Typhimurium vaccine strain to up-regulate B7-1 and B7-2 on antigen-presenting cells and to examine the functional roles these costimulatory molecules play in mediating immune responses to Salmonella and to an expressed cloned antigen, the saliva-binding region (SBR) of antigen I/II. In vitro stimulation of B cells (B220+), macrophages (CD11b+), and dendritic cells (CD11c+) with S. enterica serovar Typhimurium induced an up-regulation of B7-2 and, especially, B7-1 expression. The in vivo functional roles of B7-1, B7-2, and B7-1/2 were evaluated in BALB/c wild-type and B7-1, B7-2, and B7-1/2 knockout (KO) mice following intranasal immunization with the Salmonella expressing the cloned SBR. Differential requirements for B7-1 and B7-2 were observed upon primary and secondary immunizations. Compared to wild-type controls, B7-1 and B7-2 KO mice had reduced mucosal and systemic anti-Salmonella antibody responses after a single immunization, while only B7-1 KO mice exhibited suppressed anti-Salmonella antibody responses following the second immunization. Mucosal and systemic antibody responses to SBR were reduced following the primary immunization, whereas a compensatory role for either B7-1 or B7-2 was observed after the second immunization. B7-1/2 double KO mice failed to induce detectable levels of mucosal or systemic immunoglobulin A (IgA) or IgG antibody responses to either Salmonella or SBR. These findings demonstrate that B7-1 and B7-2 can play distinct as well as redundant roles for mediating mucosal and systemic antibody responses, which are likely dependent upon the nature of the antigen.

scholarly journals Effect of Inactivation of degS on Salmonella enterica Serovar Typhimurium In Vitro and In Vivo

2005 ◽  
Vol 73 (1) ◽  
pp. 459-463 ◽  
Author(s):  
Gary Rowley ◽  
Andrew Stevenson ◽  
Jan Kormanec ◽  
Mark Roberts
Keyword(s):  
Sigma Factor ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Wild Type ◽  
Alternative Pathways ◽  
E Coli ◽  
Mammalian Tissues ◽  
Serovar Typhimurium

ABSTRACT The alternative sigma factor (RpoE σE) enables Salmonella enterica serovar Typhimurium to adapt to stressful conditions, such as oxidative stress, nutrient deprivation, and growth in mammalian tissues. Infection of mice by Salmonella serovar Typhimurium also requires σE. In Escherichia coli, activation of the σE pathway is dependent on proteolysis of the anti-sigma factor RseA and is initiated by DegS. DegS is also important in order for E. coli to cause extraintestinal infection in mice. We constructed a degS mutant of the serovar Typhimurium strain SL1344 and compared its behavior in vitro and in vivo with those of its wild-type (WT) parent and an isogenic rpoE mutant. Unlike E. coli degS strains, the Salmonella serovar Typhimurium degS strain grew as well as the WT strain at 42°C. The degS mutant survived very poorly in murine macrophages in vitro and was highly attenuated compared with the WT strain for both the oral and parenteral routes of infection in mice. However, the degS mutant was not as attenuated as the serovar Typhimurium rpoE mutant: 100- to 1,000-fold more degS bacteria than rpoE bacteria were present in the livers and spleens of mice 24 h after intraperitoneal challenge. In most assays, the rpoE mutant was more severely affected than the degS mutant and a σE-dependent reporter gene was more active in the degS mutant than the rpoE strain. These findings indicate that degS is important for activation of the σE pathway in serovar Typhimurium but that alternative pathways for σE activation probably exist.

scholarly journals A Superoxide-Hypersusceptible Salmonella enterica Serovar Typhimurium Mutant Is Attenuated but Regains Virulence in p47phox−/− Mice

2002 ◽  
Vol 70 (5) ◽  
pp. 2614-2621 ◽  
Author(s):  
Angela van Diepen ◽  
Tahar van der Straaten ◽  
Steven M. Holland ◽  
Riny Janssen ◽  
Jaap T. van Dissel
Keyword(s):  
Salmonella Enterica ◽  
Defense Mechanisms ◽  
Mononuclear Phagocytes ◽  
Wild Type ◽  
Phagocytic Cells ◽  
Bacterial Counts ◽  
Innate Defense ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica serovar Typhimurium is a gram-negative, facultative intracellular pathogen that predominantly invades mononuclear phagocytes and is able to establish persistent infections. One of the innate defense mechanisms of phagocytic cells is the production of reactive oxygen species, including superoxide. S. enterica serovar Typhimurium has evolved mechanisms to resist such radicals, and these mechanisms could be decisive in its ability to survive and replicate within macrophages. Recently, we described a superoxide-hypersusceptible S. enterica serovar Typhimurium mutant strain, DLG294, that carries a transposon in sspJ, resulting in the lack of expression of SspJ, which is necessary for resistance against superoxide and replication within macrophages. Here we show that DLG294, which is a 14028s derivative, hardly induced any granulomatous lesions in the livers upon subcutaneous infection of C3H/HeN (Ityr) mice with 3 × 104 bacteria and that its bacterial counts were reduced by 3 log units compared to those of wild-type S. enterica serovar Typhimurium 14028s on day 5 after infection. In contrast, DLG294 replicated like wild-type S. enterica serovar Typhimurium 14028s and induced a phenotypically similar liver pathology in p47phox−/− mice, which are deficient in the p47phox subunit of the NADPH oxidase complex and which do not produce superoxide. Consistent with these results, DLG294 reached bacterial counts identical to those of wild-type S. enterica serovar Typhimurium 14028s in bone marrow-derived macrophages from p47phox−/− mice and in X-CGD PLB-985 cells at 24 h after challenge. These results indicate that SspJ plays a role in the bacterium's resistance to oxidative stress and in the survival and replication of S. enterica serovar Typhimurium both in vitro and in vivo.

scholarly journals Absence of Platelet Endothelial Cell Adhesion Molecule 1, PECAM-1/CD31,In VivoIncreases Resistance to Salmonella enterica Serovar Typhimurium in Mice

2013 ◽  
Vol 81 (6) ◽  
pp. 1952-1963 ◽  
Author(s):  
Michael D. Lovelace ◽  
May Lin Yap ◽  
Jana Yip ◽  
William Muller ◽  
Odilia Wijburg ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Inflammatory Responses ◽  
Bacterial Load ◽  
Host Cells ◽  
Dependent Manner ◽  
Wild Type ◽  
Mesenteric Lymph Nodes ◽  
Serovar Typhimurium

ABSTRACTPECAM-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 primaryin vivoinfection withSalmonella entericaserovar Typhimurium and inin vitroinflammatory responses of peritoneal macrophages. Lectin profiling showed that cellular PECAM-1 and recombinant human PECAM-1-Ig chimera contain high levels of mannose sugars andN-acetylglucosamine. Consistent with this carbohydrate pattern, both recombinant human and murine PECAM-1-Ig chimeras were shown to bindS. Typhimurium in a dose-dependent mannerin vitro. Using oral and fecal-oral transmission models ofS. Typhimurium SL1344 infection, PECAM-1−/−mice were found to be more resistant toS. Typhimurium infection than wild-type (WT) C57BL/6 mice. While fecal shedding ofS. 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. Followingin vitrostimulation of macrophages with either wholeS. 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 withS. Typhimurium, including binding to host cells, extraintestinal spread to deeper tissues, and regulation of inflammatory cytokine production by infected macrophages.

scholarly journals The Homolog of the Gene bstA of the BTP1 Phage from Salmonella enterica Serovar Typhimurium ST313 Is an Antivirulence Gene in Salmonella enterica Serovar Dublin

2017 ◽  
Vol 86 (1) ◽  
Author(s):  
Ana Herrero-Fresno ◽  
Irene Cartas Espinel ◽  
Malene Roed Spiegelhauer ◽  
Priscila Regina Guerra ◽  
Karsten Wiber Andersen ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Type Strain ◽  
Wild Type Strain ◽  
Luria Bertani ◽  
Wild Type ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Cattle Blood

ABSTRACTIn a previous study, a novel virulence gene,bstA, identified in aSalmonella entericaserovar Typhimurium sequence type 313 (ST313) strain was found to be conserved in all publishedSalmonella entericaserovar Dublin genomes. In order to analyze the role of this gene in the host-pathogen interaction inS. Dublin, a mutant where this gene was deleted (S. Dublin ΔbstA) and a mutant which was further genetically complemented withbstA(S. Dublin 3246-C) were constructed and tested in models ofin vitroandin vivoinfection as well as during growth competition assays in M9 medium, Luria-Bertani broth, and cattle blood. In contrast to the results obtained for a strain ofS. Typhimurium ST313, the lack ofbstAwas found to be associated with increased virulence inS. Dublin. Thus,S. Dublin ΔbstAshowed higher levels of uptake than the wild-type strain during infection of mouse and cattle macrophages and higher net replication within human THP-1 cells. Furthermore, during mouse infections,S. Dublin ΔbstAwas more virulent than the wild type following a single intraperitoneal infection and showed an increased competitive index during competitive infection assays. Deletion ofbstAdid not affect either the amount of cytokines released by THP-1 macrophages or the cytotoxicity toward these cells. The histology of the livers and spleens of mice infected with the wild-type strain and theS. Dublin ΔbstAmutant revealed similar levels of inflammation between the two groups. The gene was not important for adherence to or invasion of human epithelial cells and did not influence bacterial growth in rich medium, minimal medium, or cattle blood. In conclusion, a lack ofbstAaffects the pathogenicity ofS. Dublin by decreasing its virulence. Therefore, it might be regarded as an antivirulence gene in this serovar.

scholarly journals TheIn VitroRedundant Enzymes PurN and PurT Are Both Essential for Systemic Infection of Mice in Salmonella enterica Serovar Typhimurium

2016 ◽  
Vol 84 (7) ◽  
pp. 2076-2085 ◽  
Author(s):  
Lotte Jelsbak ◽  
Mie I. B. Mortensen ◽  
Mogens Kilstrup ◽  
John E. Olsen
Keyword(s):  
Salmonella Enterica ◽  
Single Gene ◽  
Systemic Infection ◽  
Gene Deletions ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Genes Encoding ◽  
Glycine Cleavage

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 redundantin vitroinSalmonella entericaserovar 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 ΔpurTmutant multiplied as fast as the wild-type strain in cultured J774A.1 macrophages, net multiplication of the ΔpurNmutant was reduced approximately 50% in 20 h. The attenuation of the ΔpurTmutant 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 C1unitsin vivo(CI = 0.03 ± 0.03). In contrast, GlyA was the only important enzyme for the formation of C1unitsin vitro. The results with the ΔgcvTmutant further revealed that formation of serine by SerA and further conversion of serine into C1units and glycine by GlyA were not sufficient to ensure C1formation inS. Typhimuriumin vivo. The results of the present study call for reinvestigations of the concept of metabolic redundancy inS. Typhimuriumin vivo.

Salmonella enterica Serovar Typhimurium HtrA: regulation of expression and role of the chaperone and protease activities during infection

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 873-881 ◽  
Author(s):  
Claire Lewis ◽  
Henrieta Skovierova ◽  
Gary Rowley ◽  
Bronislava Rezuchova ◽  
Dagmar Homerova ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Protease Activity ◽  
Pdz Domain ◽  
Proximal Promoter ◽  
Wild Type ◽  
Regulation Of Expression ◽  
Serovar Typhimurium

HtrA is a bifunctional stress protein required by many bacterial pathogens to successfully cause infection. Salmonella enterica serovar Typhimurium (S. Typhimurium) htrA mutants are defective in intramacrophage survival and are highly attenuated in mice. Transcription of htrA in Escherichia coli is governed by a single promoter that is dependent on σ E (RpoE). S. Typhimurium htrA also possesses a σ E-dependent promoter; however, we found that the absence of σ E had little effect on production of HtrA by S. Typhimurium. This suggests that additional promoters control expression of htrA in S. Typhimurium. We identified three S. Typhimurium htrA promoters. Only the most proximal promoter, htrAp3, was σ E dependent. The other promoters, htrAp1 and htrAp2, are probably recognized by the principal sigma factor σ 70. These two promoters were constitutively expressed but were also slightly induced by heat shock. Thus expression of htrA is different in S. Typhimurium and E. coli. The role of HtrA is to deal with misfolded/damaged proteins in the periplasm. It can do this either by degrading (protease activity) or folding/capturing (chaperone/sequestering, C/S, activity) the aberrant protein. We investigated which of these functions are important to S. Typhimurium in vitro and in vivo. Point or deletion mutants of htrA that encode variant HtrA molecules have been used in previous studies to investigate the role of different regions of HtrA in C/S and protease activity. These htrA variants were placed under the control of the S. Typhimurium htrAP123 promoters and expressed in a S. Typhimurium htrA mutant, GVB1343. Both wild-type HtrA and HtrA (HtrA S210A) lacking protease activity enabled GVB1343 to grow at high temperature (46 °C). Both molecules also significantly enhanced the growth/survival of GVB1343 in the liver and spleen of mice during infection. However, expression of wild-type HtrA enabled GVB1343 to grow to much higher levels than expression of HtrA S210A. Thus both the protease and C/S functions of HtrA operate in vivo during infection but the protease function is probably more important. Absence of either PDZ domain completely abolished the ability of HtrA to complement the growth defects of GVB1343 in vitro or in vivo.

scholarly journals Effect of Deletion of Genes Involved in Lipopolysaccharide Core and O-Antigen Synthesis on Virulence and Immunogenicity of Salmonella enterica Serovar Typhimurium

2011 ◽  
Vol 79 (10) ◽  
pp. 4227-4239 ◽  
Author(s):  
Qingke Kong ◽  
Jiseon Yang ◽  
Qing Liu ◽  
Praveen Alamuri ◽  
Kenneth L. Roland ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lipid A ◽  
Outer Core ◽  
Wild Type ◽  
Core Oligosaccharide ◽  
Content Type ◽  
O Antigen ◽  
Serovar Typhimurium

ABSTRACTLipopolysaccharide (LPS) is a major virulence factor ofSalmonella entericaserovar Typhimurium and is composed of lipid A, core oligosaccharide (C-OS), and O-antigen polysaccharide (O-PS). While the functions of the gene products involved in synthesis of core and O-antigen have been elucidated, the effect of removing O-antigen and core sugars on the virulence and immunogenicity ofSalmonella entericaserovar Typhimurium has not been systematically studied. We introduced nonpolar, defined deletion mutations inwaaG(rfaG),waaI(rfaI),rfaH,waaJ(rfaJ),wbaP(rfbP),waaL(rfaL), orwzy(rfc) into wild-typeS.Typhimurium. The LPS structure was confirmed, and a number ofin vitroandin vivoproperties of each mutant were analyzed. All mutants were significantly attenuated compared to the wild-type parent when administered orally to BALB/c mice and were less invasive in host tissues. Strains with ΔwaaGand ΔwaaImutations, in particular, were deficient in colonization of Peyer's patches and liver. This deficiency could be partially overcome in the ΔwaaImutant when it was administered intranasally. In the context of an attenuated vaccine strain delivering the pneumococcal antigen PspA, all of the mutations tested resulted in reduced immune responses against PspA andSalmonellaantigens. Our results indicate that nonreversible truncation of the outer core is not a viable option for developing a live oralSalmonellavaccine, while awzymutant that retains one O-antigen unit is adequate for stimulating the optimal protective immunity to homologous or heterologous antigens by oral, intranasal, or intraperitoneal routes of administration.

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