A comparison of cecal colonization of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serotype Typhimurium in white leghorn chicks and <Emphasis Type="Italic">Salmonella</Emphasis>-resistant mice

Background  

Salmonellosis is one of the most important bacterial food borne illnesses worldwide. A major source of infection for humans is consumption of chicken or egg products that have been contaminated withSalmonella entericaserotype Typhimurium, however our knowledge regarding colonization and persistence factors in the chicken is small.     

Eradication of <Emphasis Type="Italic">Salmonella</Emphasis> Typhimurium infection in a murine model of typhoid fever with the combination of probiotic <Emphasis Type="Italic">Lactobacillus fermentum</Emphasis> ME-3 and ofloxacin

Background  

The aim of the study was to detect whether in experimental Salmonella enterica Typhimurium infection the probiotic Lactobacillus fermentum ME-3 in combination with fluoroquinolone therapy would eradicate S. Typhimurium, prevent the development of liver and spleen granulomas and improve the indices of oxidative stress in the ileum mucosa.     

The PagN protein of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Typhimurium is an adhesin and invasin

Background  

The pagN gene of Salmonella enterica serovar Typhimurium is a PhoP-regulated gene that is up-regulated during growth within macrophages and in vivo in murine models of infection. The PagN protein displays similarity to the Hek and Tia invasins/adhesins of Escherichia coli. Thus far no function has been ascribed to the PagN protein.     

Rapid screening of <Emphasis Type="Italic">Salmonella enterica</Emphasis>serovars Enteritidis,Hadar, Heidelberg and Typhimurium using a serologically-correlative allelotyping PCR targeting the O and H antigen alleles

Background  

Classical Salmonella serotyping is an expensive and time consuming process that requires implementing a battery of O and H antisera to detect 2,541 different Salmonella enterica serovars. For these reasons, we developed a rapid multiplex polymerase chain reaction (PCR)-based typing scheme to screen for the prevalent S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.     

Development of stable reporter system cloning <Emphasis Type="Italic">luxCDABE</Emphasis> genes into chromosome of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serotypes using Tn7 transposon

Background  

Salmonellosis may be a food safety problem when raw food products are mishandled and not fully cooked. In previous work, we developed bioluminescent Salmonella enterica serotypes using a plasmid-based reporting system that can be used for real-time monitoring of the pathogen's growth on food products in short term studies. In this study, we report the use of a Tn7-based transposon system for subcloning of luxCDABE genes into the chromosome of eleven Salmonella enterica serotypes isolated from the broiler production continuum.     

Systematic analysis of the regulation of type three secreted effectors in <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Typhimurium

Background  

The type III secretion system (TTSS) is an important virulence determinant of Gram-negative bacterial pathogens. It enables the injection of effector proteins into the cytosol of eukaryotic cells. These effectors ultimately manipulate the cellular functions of the infected organism. Salmonella enterica serovar Typhimurium encodes two virulence associated TTSSs encoded by the Salmonella Pathogenicity Islands (SPI) 1 and 2 that are required for the intestinal and systemic phases of the infection, respectively. However, recent studies suggest that the roles of these TTSSs are not restricted to these compartments. The regulation of TTSSs in Salmonella is very complex with several regulators operating to activate or to repress expression depending on the environmental conditions.     

Adaptation of <Emphasis Type="Italic">Salmonella enterica</Emphasis> Hadar under static magnetic field: effects on outer membrane protein pattern

Background  

Salmonella enterica serovar Hadar (S. Hadar) is a highly prevalent foodborne pathogen and therefore a major cause of human gastroenteritis worldwide. Outer membrane proteins whose production is often regulated by environmental conditions also play important roles in the adaptability of bacterial pathogens to various environments.     

Antimicrobial activity of copper surfaces against suspensions of <Emphasis Type="Italic">Salmonella enterica</Emphasis> and <Emphasis Type="Italic">Campylobacter jejuni</Emphasis>

Background  

Salmonella enterica and Campylobacter jejuni are amongst the more prevalent bacterial pathogens that cause foodborne diseases. These microorganisms are common contaminants of poultry and poultry products. This study was aimed to evaluate the antibacterial activity of metallic copper surfaces on these important enteropathogens, and to determine the potential acquisition of copper by food exposed to this metal.     

Mass spectrometry-based quantitative proteomic analysis of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Enteritidis protein expression upon exposure to hydrogen peroxide

Background  

Salmonella enterica, a common food-borne bacterial pathogen, is believed to change its protein expression profile in the presence of different environmental stress such as that caused by the exposure to hydrogen peroxide (H₂O₂), which can be generated by phagocytes during infection and represents an important antibacterial mechanism of host cells. Among Salmonella proteins, the effectors of Salmonella pathogenicity island 1 and 2 (SPI-1 and SPI-2) are of particular interest since they are expressed during host infection in vivo and are important for invasion of epithelial cells and for replication in organs during systemic infection, respectively. However, the expression profiles of these proteins upon exposure to H₂O₂ or to host cells in vivo during the established phase of systemic infection have not been extensively studied.     

Effects of <Emphasis Type="Italic">crp</Emphasis> deletion in <Emphasis Type="Italic">Salmonella enterica</Emphasis> serotype Gallinarum

Background  

Salmonella enterica serotype Gallinarum (S. Gallinarum) remains an important pathogen of poultry, especially in developing countries. There is a need to develop effective and safe vaccines. In the current study, the effect of crp deletion was investigated with respect to virulence and biochemical properties and the possible use of a deletion mutant as vaccine candidate was preliminarily tested.     

Involvement of SPI-2-encoded SpiC in flagellum synthesis in Salmonella enterica serovar Typhimurium

Background  

SpiC encoded within Salmonella pathogeniCity island 2 on the Salmonella enterica serovar Typhimurium chromosome is required for survival within macrophages and systemic infection in mice. Additionally, SpiC contributes to Salmonella-induced activation of the signal transduction pathways in macrophages by affecting the expression of FliC, a component of flagella filaments. Here, we show the contribution of SpiC in flagellum synthesis.     

The Salmonella PathogeniCity Island (SPI) 1 contributes more than SPI2 to the colonization of the chicken by Salmonella enterica serovar Typhimurium

Background  

Salmonella enterica serovar Typhimurium (Typhimurium) is an important pathogen that infects a broad range of hosts. In humans, Typhimurium causes a gastroenteritis characterized by vomiting, diarrhea, and abdominal pains. Typhimurium infection occurs mainly through the ingestion of contaminated food including poultry, pork, eggs, and milk. Chickens that are asymptomatic carriers of Typhimurium constitute a potential reservoir for infection. The type three secretion systems encoded by Salmonella pathogeniCity islands (SPI) 1 and 2 are major virulence factors of Salmonella. However, only a few studies have investigated their role during the infection of chickens.     

Outer membrane protein a of <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Typhimurium activates dendritic cells and enhances Th1 polarization

Background  

Typhoid, which is caused by Salmonella enterica serovar Typhimurium, remains a major health concern worldwide. Multidrug-resistant strains of Salmonella have emerged which exhibit increased survivability and virulence, thus leading to increased morbidity. However, little is known about the protective immune response against this microorganism. The outer membrane protein (Omp)A of bacteria plays an important role in pathogenesis.     

Allele distribution and genetic diversity of VNTR loci in <Emphasis Type="Italic">Salmonella enterica</Emphasis>serotype Enteritidis isolates from different sources

Background  

Salmonella enterica serotype Enteritidis (S. Enteritidis) is a zoonotic pathogen, which can be found in many sources including animals and the environment. However, little is known about the molecular relatedness among S. Enteritidis isolates from different sources. We have applied multiple-locus variable number tandem repeat analysis (MLVA) to study the genetic diversity of S. Enteritidis isolates from human and non-human sources.     

Efficacy of European starling control to reduce <Emphasis Type="Italic">Salmonella enterica</Emphasis> contamination in a concentrated animal feeding operation in the Texas panhandle

Background  

European starlings (Sturnus vulgaris) are an invasive bird species known to cause damage to plant and animal agriculture. New evidence suggests starlings may also contribute to the maintenance and spread of diseases within livestock facilities. Identifying and mitigating the risk pathways that contribute to disease in livestock is necessary to reduce production losses and contamination of human food products. To better understand the impact starlings have on disease transmission to cattle we assessed the efficacy of starling control as a tool to reduce Salmonella enterica within a concentrated animal feeding operation. We matched a large facility, slated for operational control using DRC-1339 (3-chloro-4-methylaniline hydrochloride, also 3-chloro p-toluidine hydrochloride, 3-chloro-4-methylaniline), with a comparable reference facility that was not controlling birds. In both facilities, we sampled cattle feed, cattle water and cattle feces for S. enterica before and after starling control operations.     

Analysis of the ArcA regulon in anaerobically grown <Emphasis Type="Italic">Salmonella enterica sv</Emphasis>. Typhimurium

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.     

YqiC of Salmonella enterica serovar Typhimurium is a membrane fusogenic protein required for mice colonization

Background  

Salmonella enterica serovar Typhimurium is an intracellular bacterial pathogen which can colonize a variety of hosts, including human, causing syndromes that vary from gastroenteritis and diarrhea to systemic disease.     

Proteome analysis of serovars Typhimurium and Pullorum of <Emphasis Type="Italic">Salmonella enterica</Emphasis> subspecies I

Background  

Salmonella enterica subspecies I includes several closely related serovars which differ in host ranges and ability to cause disease. The basis for the diversity in host range and pathogenic potential of the serovars is not well understood, and it is not known how host-restricted variants appeared and what factors were lost or acquired during adaptations to a specific environment. Differences apparent from the genomic data do not necessarily correspond to functional proteins and more importantly differential regulation of otherwise identical gene content may play a role in the diverse phenotypes of the serovars of Salmonella.     

Surface display of Salmonella epitopes in <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Staphylococcus carnosus</Emphasis>

Background  

Salmonella enterica serotype Enteritidis (SE) is considered to be one of the most potent pathogenic Salmonella serotypes causing food-borne disease in humans. Since a live bacterial vaccine based on surface display of antigens has many advantages over traditional vaccines, we have studied the surface display of the SE antigenic proteins, H:gm and SefA in Escherichia coli by the β-autotransporter system, AIDA. This procedure was compared to protein translocation in Staphylococcus carnosus, using a staphylococci hybrid vector earlier developed for surface display of other vaccine epitopes.     

Functional dissection of translocon proteins of the <Emphasis Type="Italic">Salmonella</Emphasis> Pathogenicity Island 2-encoded type III secretion system

Background  

Type III secretion systems (T3SS) are essential virulence factors of most Gram-negative bacterial pathogens. T3SS deliver effector proteins directly into the cytoplasm of eukaryotic target cells and for this function, the insertion of a subset of T3SS proteins into the target cell membrane is important. These proteins form hetero-oligomeric pores acting as translocon for the delivery of effector proteins. Salmonella enterica is a facultative intracellular pathogen that uses the Salmonella Pathogenicity Island 2 (SPI2)-encoded T3SS to manipulate host cells in order to survive and proliferate within the Salmonella-containing vacuole of host cells. Previous work showed that SPI2-encoded SseB, SseC and SseD act to form the translocon of the SPI2-T3SS.