TY - JOUR. T1 - Unusual Salmonella enterica serotype Typhimurium isolate producing CMY-7, SHV-9 and OXA-30 β-lactamases. AU - Hanson, Nancy D.. AU - Moland, Ellen S.. AU - Hossain, Ashfaque. AU - Neville, Stephen A.. AU - Gosbell, Iain B.. AU - Thomson, Kenneth S.. N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.. PY - 2002. Y1 - 2002. N2 - β-Lactam resistance in Salmonella isolates is increasing. This paper describes the combination of three different β-lactamases, OXA-30, SHV-9 and CMY-7, expressed by an isolate of Salmonella enterica serotype Typhimurium. This is the first report of an isolate of Salmonella having both an extended-spectrum β-lactamase and an AmpC β-lactamase.. AB - β-Lactam resistance in Salmonella isolates is increasing. This paper describes the combination of three different β-lactamases, OXA-30, SHV-9 and CMY-7, expressed by an isolate of Salmonella enterica serotype Typhimurium. This is the first report of an isolate of Salmonella having both an ...
Exit of salmonellae from the intestinal lumen involves invasion of intestinal epithelial cells, and this invasion relies upon the production of a type III secretory apparatus and protein effector molecules (including prgH and its cotranscribed genes) from SPI-1. These secreted effector molecules mediate changes in host epithelial cells, causing them to ruffle and engulf the bacterium. Our previous work showed that the transcription of prgH, which is part of an operon encoding members of the SPI-1-encoded secretion apparatus, is repressed in the presence of bile. Based on this preliminary observation, in this work, we show that the interaction of serovar Typhimurium with bile dramatically affects its invasive ability by downregulating the transcription of invasion gene regulators, which results in a marked decrease in the transcription of SPI-1 genes involved in epithelial cell entry.. A complex set of transcriptional activators interact to regulate serovar Typhimurium invasion of epithelial ...
TY - JOUR. T1 - Three-dimensional tissue assemblies. T2 - Novel models for the study of Salmonella enterica serovar typhimurium pathogenesis. AU - Nickerson, C. A.. AU - Goodwin, T. J.. AU - Terlonge, J.. AU - Ott, C. M.. AU - Buchanan, K. L.. AU - Uicker, W. C.. AU - Emami, K.. AU - LeBlanc, C. L.. AU - Ramamurthy, R.. AU - Clarke, M. S.. AU - Vanderburg, C. R.. AU - Hammond, T.. AU - Pierson, D. L.. PY - 2001. Y1 - 2001. N2 - 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 ...
TY - JOUR. T1 - Enterobacterial common antigen mutants of Salmonella enterica serovar typhimurium establish a persistent infection and provide protection against subsequent lethal challenge. AU - Gilbreath, Jeremy J.. AU - Dodds, Jennifer Colvocoresses. AU - Rick, Paul D.. AU - Soloski, Mark J.. AU - Merrell, D. Scott. AU - Metcalf, Eleanor S.. PY - 2012/1. Y1 - 2012/1. N2 - Infection with Salmonella spp. is a significant source of disease globally. A substantial proportion of these infections are caused by Salmonella enterica serovar Typhimurium. Here, we characterize the role of the enterobacterial common antigen (ECA), a surface glycolipid ubiquitous among enteric bacteria, in S. Typhimurium pathogenesis. Construction of a defined mutation in the UDP-N-acetylglucosamine-1-phosphate transferase gene, wecA, in two clinically relevant strains of S. Typhimurium, TML and SL1344, resulted in strains that were unable to produce ECA. Loss of ECA did not affect the gross cell surface ultrastructure, ...
Salmonella pathogenicity island (SPI)-1 is essential for invasion of non-phagocytic cells, whereas SPI-2 is required for intracellular survival and proliferation in phagocytes. Some SPI-1 effectors, however, are induced upon invasion of both phagocytic and non-phagocytic cells, suggesting that they may also be required post-invasion. In the present work, the presence was analysed of SipA, SopA, SopB, SopD and SopE2 effector proteins of Salmonella enterica serovar Typhimurium in vitro and in vivo during murine salmonellosis. Tagged (3×FLAG) strains of S. enterica serovar Typhimurium were inoculated intraperitoneally or intragastrically to BALB/c mice and recovered from the spleen and mesenteric lymph nodes of moribund mice. Tagged proteins were detected by SDS-PAGE and immunoblotting with anti-FLAG antibodies. In vitro experiments showed that SPI-1 effector proteins SipA, SopA, SopB, SopD and SopE2 were secreted under SPI-1 conditions. Interestingly, it was found that S. enterica serovar Typhimurium
Salmonella enterica serovar Typhimurium can be internalized by immature dendritic cells (DCs). The interacting host and bacterial molecules initiating this process remain uncharacterized. The objective of this study was to investigate whether specific fimbriae are involved in the early step of binding and uptake of Salmonella by DCs. Type 1 fimbriated S. enterica serovar Typhimurium or recombinant Escherichia coli expressing the type 1 fimbriae showed a significantly greater ability to attach to murine bone-marrow-derived DCs than non-fimbriated bacteria. The FimH adhesin was required for efficient interactions with DCs, since fimbriated fimH mutants were impaired in both binding and internalization. Finally, the internalization involved a FimH-dependent process but did not require sipB, a gene essential for Salmonella-mediated invasion of mammalian epithelial cells. Collectively, these data suggest that the bacterial interaction of DCs through the type 1 fimbrial adhesin FimH is sufficient to target S.
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
Members of Salmonella enterica are frequently involved in egg and egg product related human food poisoning outbreaks worldwide. In Australia, Salmonella Typhimurium is frequently involved in egg and egg product related foodborne illness and Salmonella Mbandaka has also been found to be a contaminant of the layer farm environment. The ability possessed by Salmonella Enteritidis to colonise reproductive organs and contaminate developing eggs has been well described. However, there are few studies investigating this ability for Salmonella Typhimurium. The hypothesis of this study was that the Salmonella Typhimurium can colonise the gut for a prolonged period of time and that horizontal infection through feces is the main route of egg contamination. At 14 weeks of age hens were orally infected with either S. Typhimurium PT 9 or S. Typhimurium PT 9 and Salmonella Mbandaka. Salmonella shedding in feces and eggs was monitored for 15 weeks post infection. Egg shell surface and internal contents of eggs laid
The immobilization of a whole microbial cell is an important process used in nanotechnology of biosensors and other related fields, especially the development of bio-hybrid materials based on live organisms and inorganic compounds. Here, we described an essay to develop a bio-hybrid material based on Salmonella Typhimurium cells and layered double hydroxides (LDH). The synthetic clays have a good capacity to be a host matrix for immobilization of live entity like bacteria. The incorporation of LDH in the nutritive broth shows the capacity of bacteria to grow under the inorganic conditions. The immobilization of bacteria onto the LDH Layer deposited on gold wafers was successfully done and the verification of the final material consistence was given by Fourier transform infrared spectroscopy (FTIR) analysis that shows the possibility of various covalent links that can be established between the polar functional group of the cell and the interlayer level in the LDH. The roughness of the surface ...
TY - JOUR. T1 - RosE represses Std fimbrial expression in Salmonella enterica serotype Typhimurium. AU - Chessa, Daniela. AU - Winter, Maria G.. AU - Nuccio, Sean Paul. AU - Tükel, Çagla. AU - Baumler, Andreas J. PY - 2008/5. Y1 - 2008/5. N2 - 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 ...
Bacterial fecal shedding by persistently infected hosts is the major source of new infection and disease for a number of bacterial pathogens. Yet, this pivotal phase of the pathogenesis of infection has been the most difficult phase to model experimentally. Infection of 129X1/SvJ (Nramp1+/+) mice with Salmonella serovar Typhimurium leads to a persistent infection (38). We show here that animals persistently infected with Salmonella serovar Typhimurium can transmit the infection to naïve animals housed in the same cage. However, there was considerable variability among mice in the ability to transmit bacteria to naïve animals. Also, we noted that the shedding levels varied significantly among individual donor mice and from those of exposed infected animals. We found that only a subset of infected mice, about 27%, shed high levels of Salmonella serovar Typhimurium in their feces (,108 CFU/g) and efficiently served as a reservoir to transmit the organisms to naïve individuals. We designated ...
1998) Characterisation of recently emerged multiple antibiotic-resistant Salmonella enterica serovar typhimurium DT104 and other multiresistant phage types from Danish pig ...
Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S. Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S. Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S. Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S. Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S. Typhimurium (serovar I:4,[5],12:i:-sequence type 34 [ST34]) has been introduced into ...
TY - JOUR. T1 - FimY of Salmonella enterica serovar Typhimurium functions as a DNA-binding protein and binds the fimZ promoter. AU - Wang, Ke Chuan. AU - Hsu, Yuan Hsun. AU - Huang, Yi Ning. AU - Lin, Jiunn Horng. AU - Yeh, Kuang Sheng. PY - 2014. Y1 - 2014. N2 - 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 ...
BioAssay record AID 532763 submitted by ChEMBL: Antimicrobial activity against Salmonella serovar Typhimurium SL1344 expressing ramA::aph mutant by broth dilution method in presence of chlorpromazine.
Intestinal epithelial cells (IECs) play a key role in regulating immune responses and controlling infection. However, the direct role of IECs in restricting pathogens remains incompletely understood. Here, we provide evidence that IL-22 primed intestinal organoids derived from healthy human induced pluripotent stem cells (hIPSCs) to restrict Salmonella enterica serovar Typhimurium SL1344 infection. A combination of transcriptomics, bacterial invasion assays, and imaging suggests that IL-22-induced antimicrobial activity is driven by increased phagolysosomal fusion in IL-22-pretreated cells. The antimicrobial phenotype was absent in hIPSCs derived from a patient harboring a homozygous mutation in the IL10RB gene that inactivates the IL-22 receptor but was restored by genetically complementing the IL10RB deficiency. This study highlights a mechanism through which the IL-22 pathway facilitates the human intestinal epithelium to control microbial infection.
article{3186904, abstract = {Salmonella enterica serovar Typhimurium is a main cause of bacterial food-borne diseases. As Salmonella can form biofilms in which it is better protected against antimicrobial agents on a wide diversity of surfaces, it is of interest to explore ways to inhibit biofilm formation. Brominated furanones, originally extracted from the marine alga Delisea pulchra, are known to interfere with biofilm formation in several pathogens. In this study, we have synthesized a small focused library of brominated furanones and tested their activity against S. enterica serovar Typhimurium biofilm formation. We show that several furanones inhibit Salmonella biofilm formation at non-growth-inhibiting concentrations. The most interesting compounds are (Z)-4-bromo-5-(bromomethylene)3- alkyl-2(5H)-furanones with chain lengths of two to six carbon atoms. A microarray study was performed to analyze the gene expression profiles of Salmonella in the presence of (Z)-4-bromo-5-(bromomethylene)3- ...
The intestinal mucosa forms the first line of defense against infections mediated by enteric pathogens such as salmonellae. Here we exploited intestinal organoids (iHOs) generated from human induced pluripotent stem cells (hIPSCs) to explore the interaction of Salmonella enterica serovar Typhimurium with iHOs. Imaging and RNA sequencing were used to analyze these interactions, and clear changes in transcriptional signatures were detected, including altered patterns of cytokine expression after the exposure of iHOs to bacteria. S. Typhimurium microinjected into the lumen of iHOs was able to invade the epithelial barrier, with many bacteria residing within Salmonella-containing vacuoles. An S. Typhimurium invA mutant defective in the Salmonella pathogenicity island 1 invasion apparatus was less capable of invading the iHO epithelium. Hence, we provide evidence that hIPSC-derived organoids are a promising model of the intestinal epithelium for assessing interactions with enteric pathogens ...
Invasive Salmonella typhimurium induces dramatic cytoskeletal changes on the membrane surface of mammalian epithelial cells and RAW264.7 macrophages as part of its entry mechanism. Noninvasive S. typhimurium strains are unable to induce this membrane ruffling. Invasive S. typhimurium strains invade RAW264.7 macrophages in 2 h with 7- to 10-fold higher levels than noninvasive strains. Invasive S. typhimurium and Salmonella typhi, independent of their ability to replicate intracellularly, are cytotoxic to RAW264.7 macrophages and, to a greater degree, to murine bone marrow-derived macrophages. Here, we show that the macrophage cytotoxicity mediated by invasive Salmonella is apoptosis, as shown by nuclear morphology, cytoplasmic vacuolization, and host cell DNA fragmentation. S. typhimurium that enter cells causing ruffles but are mutant for subsequent intracellular replication also initiate host cell apoptosis. Mutant S. typhimurium that are incapable of inducing host cell membrane ruffling fail ...
Invasive Salmonella typhimurium induces dramatic cytoskeletal changes on the membrane surface of mammalian epithelial cells and RAW264.7 macrophages as part of its entry mechanism. Noninvasive S. typhimurium strains are unable to induce this membrane ruffling. Invasive S. typhimurium strains invade RAW264.7 macrophages in 2 h with 7- to 10-fold higher levels than noninvasive strains. Invasive S. typhimurium and Salmonella typhi, independent of their ability to replicate intracellularly, are cytotoxic to RAW264.7 macrophages and, to a greater degree, to murine bone marrow-derived macrophages. Here, we show that the macrophage cytotoxicity mediated by invasive Salmonella is apoptosis, as shown by nuclear morphology, cytoplasmic vacuolization, and host cell DNA fragmentation. S. typhimurium that enter cells causing ruffles but are mutant for subsequent intracellular replication also initiate host cell apoptosis. Mutant S. typhimurium that are incapable of inducing host cell membrane ruffling fail ...
Placental infection by Salmonella enterica typhimurium in a murine model : mechanisms of pathogenesis and role of inflammatory cell death
Whole-genome sequencing is rapidly replacing current molecular typing methods for surveillance purposes. Our study evaluates core-genome single-nucleotide polymorphism analysis for outbreak detection and linking of sources of Salmonella enterica serovar Typhimurium and its monophasic variants during a 7-month surveillance period in Denmark. We reanalyzed and defined 8 previously characterized outbreaks from the phylogenetic relatedness of the isolates, epidemiologic data, and food traceback investigations. All outbreaks were identified, and we were able to exclude unrelated and include additional related human cases. We were furthermore able to link possible food and veterinary sources to the outbreaks. Isolates clustered according to sequence types (STs) 19, 34, and 36. Our study shows that core-genome single-nucleotide polymorphism analysis is suitable for surveillance and outbreak investigation for Salmonella Typhimurium (ST19 and ST36), but whole genome-wide analysis may be required for the tight
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 ...
In order to deploy virulence factors at appropriate times and locations, microbes must rapidly sense and respond to various metabolite signals. Previously, we showed a transient elevation of the methionine-derived metabolite methylthioadenosine (MTA) concentration in serum during systemic Salmonella enterica serovar Typhimurium infection. Here we explored the functional consequences of increased MTA concentrations on S Typhimurium virulence. We found that MTA, but not other related metabolites involved in polyamine synthesis and methionine salvage, reduced motility, host cell pyroptosis, and cellular invasion. Further, we developed a genetic model of increased bacterial endogenous MTA production by knocking out the master repressor of the methionine regulon, metJ Like MTA-treated S Typhimurium, the ΔmetJ mutant displayed reduced motility, host cell pyroptosis, and invasion. These phenotypic effects of MTA correlated with suppression of flagellar and Salmonella pathogenicity island 1 (SPI-1) networks. S
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 ...
Salmonella can survive for long periods under extreme desiccation conditions. This stress tolerance poses a risk for food safety, but relatively little is known about the molecular and cellular regulation of this adaptation mechanism. To determine the genetic components involved in Salmonellas cellular response to desiccation, we performed a global transcriptomic analysis comparing S. enterica serovar Typhimurium cells equilibrated to low water activity (aw 0.11) and cells equilibrated to high water activity (aw 1.0). The analysis revealed that 719 genes were differentially regulated between the two conditions, of which 290 genes were up-regulated at aw 0.11. Most of these genes were involved in metabolic pathways, transporter regulation, DNA replication/repair, transcription and translation, and, more importantly, virulence genes. Among these, we decided to focus on the role of sopD and sseD. Deletion mutants were created and their ability to survive desiccation and exposure to aw 0.11 was compared to
Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of Salmonella enterica serotype Typhimurium. Previous investigations indicate that static broth culture favours S. Typhimurium to produce type 1 fimbriae, while non-fimbriate bacteria are obtained by growth on solid agar media. The phenotypic expression of type 1 fimbriae in S. Typhimurium is the result of the interaction and cooperation of several genes in the fim gene cluster. Other gene products that may also participate in the regulation of type 1 fimbrial expression remain uncharacterized. In the present study, transposon insertion mutagenesis was performed on S. Typhimurium to generate a library to screen for those mutants that would exhibit different type 1 fimbrial phenotypes than the parental strain. Eight-two mutants were obtained from 7,239 clones screened using the yeast agglutination test. Forty-four mutants produced type 1 fimbriae on both solid agar and static broth media, while none of the other 38
The comparison of the publicly available genomes of the virulent Salmonella serovar Typhimurium strains SL1344, 14028s, D23580 to that of the virulence attenuated isolate LT2 revealed the absence of a full sequence of bacteriophage ST64B in the latter. Four selected ST64B regions of unknown function (sb7-sb11, sb46, sb49-sb50, and sb54) were mapped by PCR in two strains collections; 1) 310 isolates of S. Typhimurium from human blood or stool samples and from food, animal and environmental reservoirs, and 2) 90 isolates belonging to other serovars. The region sb49-sb50 was found to be unique to S. Typhimurium and was strongly associated to strains isolated from blood samples (100% and 28.4% of the blood and non-blood isolates, respectively). The region was cloned into LT2 and knocked out in SL1344 and these strains were compared to wild type isogenic strains in in vitro assays used to predict virulence association. No difference in invasion of the Int407 human cell line was observed between the ...
a CIP, ciprofloxacin; CTZ, ceftriaxone; ND, not determined. CIP (MIC, ≥4 μg/ml), Salmonella isolates with ciprofloxacin MIC of ≥4 μg/ml; CTZ (MIC, ≥4 μg/ml), Salmonella isolates with ceftriaxone MIC of ≥4 μg/ml; CIP, CTZ (MIC, ≥4 μg/ml), Salmonella isolates with both ciprofloxacin and ceftriaxone MICs of ≥4 μg/ml. ...
BACKGROUND: Salmonella infections cause gastrointestinal and systemic diseases worldwide and are the leading causes of food-borne illnesses in North America (1-4). Salmonella serotype typhimurium (ST), in particular, is increasingly becoming a major public health concern because of its ability to acquire multiple resistant genes (5,6).OBJECTIVE: To describe demographic, temporal and geographical distributions, and reported risk factors of nonoutbreak cases of ST reported to a surveillance system in Ontario.METHODOLOGY: Descriptive analyses were performed on data on salmonellosiscases reported in Ontario between 1990 and 1998. Direct age- and sex-standardized rates were computed, and temporal trend analyses were performed using simple linear regression and a general additive model with alocally weighted regression (LOESS) smoother.RESULTS: The mean annual rates of infections with all Salmonella serotypes and with ST were 27 cases per 100,000 persons and 3.7 cases per 100,000 persons, ...
A paper published in Lancet Infectious Diseases (behind a paywall) by researchers from the Institut Pasteur and the French National Reference Centre for Escherichia coli, Shigella and Salmonella generated much buzz online among those interested in antimicrobial resistance. They had studied 288 historical (1911-1969) isolates of Salmonella enterica serotype Typhimurium - a zoonotic bacterium that is one of the most common causes of non-typhoidal Salmonella…
Salmonella typhimurium. Coloured transmission electron micrograph of Salmonella typhimurium bacteria dividing. The orange areas in the centre of the cells are the sites of the genetic material. This rod-shaped, Gram-negative species is a pathogen of many animals and is the commonest cause of food poisoning (Salmonellosis) in humans. It produces enterotoxins which act on the small intestine. Infection occurs when these bacteria contaminate food such as meat, milk and eggs. Symptoms of food poisoning include abdominal pain, nausea, vomiting and diarrhoea. The infection is usually controllable and is rarely fatal. Magnification x34,300 at 6x7cm size. - Stock Image B220/0830
TY - JOUR. T1 - Multiple fimbrial adhesins are required for full virulence of Salmonella typhimurium in mice. AU - Van Der Velden, Adrianus W M. AU - Baumler, Andreas J. AU - Tsolis, Renee M. AU - Heffron, Fred. PY - 1998/6. Y1 - 1998/6. N2 - Adhesion is an important initial step during bacterial colonization of the intestinal mucosa. However, mutations in the Salmonella typhimurium fimbrial operons lpf, pef, fim only moderately alter mouse virulence. The respective adhesins may thus play only a minor role during infection or S. typhimurium may encode alternative virulence factors that can functionally compensate for their loss. To address this question, we constructed mutations in all four known fimbrial operons of S. typhimurium: fim, lpf, pef, and agf. A mutation in the agfB gene resulted in a threefold increase in the oral 50% lethal dose (LD50) of S. typhimurium for mice. In contrast, an S. typhimurium strain carrying mutations in all four fimbrial operons (quadruple mutant) had a 26-fold ...
DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4-5) macrophage vacuole and DNA relaxation correlates…
Member of the two-component regulatory system PhoP/PhoQ which regulates the expression of genes involved in virulence, adaptation to acidic and low Mg(2+) environments and resistance to host defense antimicrobial peptides. Essential for intramacrophage survival of S.typhimurium. In low periplasmic Mg(2+), PhoQ phosphorylates PhoP, resulting in the expression of PhoP-activated genes (PAG) and repression of PhoP-repressed genes (PRG). In high periplasmic Mg(2+), PhoQ dephosphorylates phospho-PhoP, resulting in the repression of PAG and may lead to expression of some PRG. Essential for transcription of spiC inside macrophages by controlling the expression of the two-component regulatory system SsrB/SpiR (SsrA) and Pir at transcriptional and post-transcriptional levels respectively. Promotes expression of the two-component regulatory system PmrA/PmrB via activation of pmrD gene. Is required to attenuate bacterial growth within fibroblast cells and to enhance bacterial resistance to bile in intestinal cells.
HilA activates the expression of Salmonella enterica serovar Typhimurium invasion genes. To learn more about regulation of hilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In addition to expected mutations, we identified Tn5 insertions in pstS, fadD, flhD, flhC, and fliA. Analysis of the pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the PhoR-PhoB two-component regulatory system, suggesting that hilA expression may be repressed by PhoRPhoB under low extracellular inorganic phosphate conditions. FadD is required for uptake and degradation of long-chain fatty acids, and our analysis of the fadD mutant indicates that hilA is regulated by a FadDdependent, FadR-independent mechanism. Thus, fatty acid derivatives may act as intracellular signals to regulate hilA expression. flhDC and fliA encode
Involvement of ISCR3 and ISCR1 with the Salmonella genomic island 1 genetic element.SGI1 is a genetic element of approximately 43 kb (15). It has been associated mainly with MDR isolates of S. enterica serovar Typhimurium phage type DT104 that are resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. This pathogen emerged in the last decade as a global animal and human health problem (15). Outbreaks of MDR S. enterica serovar Typhimurium DT104 have occurred in poultry, beef, and pigs and their food products, as well as in dairy products and salad ingredients. MDR salmonellae are very common in the United Kingdom and increasingly prevalent in many other countries (15).. Since its initial discovery in S. enterica serovar Typhimurium DT104, SGI1 has also been found in other S. enterica serovar Typhimurium phage types, i.e., DT120, DT12, DT1, and U302, and in other serovars such as Agona, Paratyphi B, Albany, Meleagridis, Newport, Emek, Cerro, Derby, Dusseldorf, ...
Spread of multidrug-resistant strains of Salmonella enterica serotype Typhimurium (S. typhimurium) is increasingly reported worldwide. The presence of a pattern of resistance to ampicillin, chloramphe
Herbicides are frequently released into both rural and urban environments. Commercial herbicide formulations induce adaptive changes in the way bacteria respond to antibiotics. Salmonella enterica sv. Typhimurium and Escherichia coli were exposed to common co-formulants of formulations, and S. enterica sv. Typhimurium was exposed to active ingredients dicamba, 2,4-D and glyphosate to determine what ingredients of the commercial formulations caused this effect. Co-formulants Tween80 and carboxymethyl cellulose induced changes in response, but the pattern of the responses differed from the active ingredients, and effect sizes were smaller. A commercial wetting agent did not affect antibiotic responses. Active ingredients induced changes in antibiotic responses similar to those caused by complete formulations. This occurred at or below recommended application concentrations. Targeted deletion of efflux pump genes largely neutralized the adaptive response in the cases of increased survival in antibiotics,
TY - JOUR. T1 - Discovery of Salmonella virulence factors translocated via outer membrane vesicles to murine macrophages. AU - Yoon, Hyunjin. AU - Ansong, Charles. AU - Adkins, Joshua N.. AU - Heffron, Fred. PY - 2011/6. Y1 - 2011/6. N2 - Salmonella enterica serovar Typhimurium, an intracellular pathogen and leading cause of food-borne illness, encodes a plethora of virulence effectors. Salmonella virulence factors are translocated into host cells and manipulate host cellular activities, providing a more hospitable environment for bacterial proliferation. In this study, we report a new set of virulence factors that is translocated into the host cytoplasm via bacterial outer membrane vesicles (OMV). PagK (or PagK1), PagJ, and STM2585A (or PagK2) are small proteins composed of ~70 amino acids and have high sequence homology to each other (,85% identity). Salmonella lacking all three homologues was attenuated for virulence in a mouse infection model, suggesting at least partial functional ...
Massis, LM et al. Anti-flagellin antibody responses elicited in mice orally immunized with attenuated Salmonella enterica serovar Typhimurium vaccine strains. Mem. Inst. Oswaldo Cruz, Sept 2008, vol.103, no.6, p.606-610. ISSN 0074- ...
Salmonella enterica serovar Typhimurium U288 has firmly established itself within the United Kingdom pig production industry. The prevalence of this highly pathogenic multidrug-resistant serovar at such a critical point in the food chain is therefore of great concern. To enhance our understanding of this microorganism, whole-genome and plasmid sequencing was performed.. ...
Runkel, S (2014) Endogenous production and detoxification of a potent cytotoxin, nitric oxide, in Salmonella enterica serovar Typhimurium and Escherichia coli. Doctoral thesis, University of East Anglia. ...
The health risks posed by Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium through the consumption of raw vegetables and vegetarian burger patties necessitates the needs for the optimization of analytical approach for their detection and enumeration in the raw vegetables, which served as potential vehicles for transmission of these pathogenic microorganisms. We sought to establish a rapid, economic and sensitive method to detect and determine the load of Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium using the most probable numbers (MPN) in combination with the multiplex polymerase chain reaction (MPCR). From the naturally contaminated one hundred and seventy five samples tested (n = 175), the overall prevalence of Salmonella spp. was 28%, Salmonella Enteritidis was 20% and Salmonella Typhimurium was 14.3%, respectively. The MPN-MPCR is a quantitative method to determine the density of cell concentration of Salmonella in all the samples (Salmonella spp. ranged from
Vaccination with Salmonella enterica serovar Typhimurium lacking DNA adenine methyltransferase confers cross-protective immunity against multiple Salmonella serotypes. The mechanistic basis is thought to be associated with the de-repression of genes that are tightly regulated when transiting from one microenvironment to another. This de-repression provides a potential means for the production of a more highly expressed and stable antigenic repertoire capable of inducing cross-protective immune responses. To identify genes encoding proteins that may contribute to cross-protective immunity, we used a Salmonella Typhimurium DNA adenine methyltransferase mutant strain (UK-1 dam mutant) derived from the parental UK-1 strain, and assessed the transcriptional profile of the UK-1 dam mutant and UK-1 strain grown under conditions that simulate the intestinal or endosomal microenvironments encountered during the infective process. As expected, the transcriptional profile of the UK-1 dam mutant identified a set
In Denmark, as part of the national laboratory-based surveillance system of human enteric infections, all Salmonella Typhimurium isolates are currently subtyped by using phage typing, antimicrobial resistance profiles, and pulsed-field gel electrophoresis (PFGE). We evaluated the value of real-time typing that uses multiple-locus-number tandem-repeats analysis (MLVA) of Salmonella enterica serotype Typhimurium (S. Typhimurium) to detect possible outbreaks. Because only a few subtypes identified by PFGE and phage typing account for most infections, we included MLVA typing in the routine surveillance in a 2-year period beginning December 2003. The 1,019 typed isolates were separated into 148 PFGE types and 373 MLVA types. Several possible outbreaks were detected and confirmed. MLVA was particularly valuable for discriminating within the most common phage types. MLVA was superior to PFGE for both surveillance and outbreak investigations of S. Typhimurium.
National Salmonella Centre (Vet), Indian Veterinary Research Institute, Izatnagar 243 122, India.. The effect of Salmonella enterica subspecies enterica serovar Typhimurium, a zoonotic serovar, on mung bean (Phaseolus aureus) cultivar Pant Mung-3 plants was studied. Inoculation of mung bean seeds with Salmonella Typhimurium (7.2 x 10(5) CFU/ml) reduced sprouting rate (P , 0.07). This effect was more pronounced at higher levels of contamination. In the soil inoculated with Salmonella Typhimurium (7.2 x 10(6) CFU/g), germination was retarded and the number of defective sprouts was also significantly higher (P , 0.002). Salmonella Typhimurium grew inside germinating seeds and plant tissues and persisted in seedlings, adult plants, and harvested seedlings dried and stored at room temperature (30 degrees C) up to 45 days. Phaseolus aureus plants grown in sterile soil was resistant to Salmonella Typhimurium infection at 15 days of age and cleared Salmonella from all the aerial parts within 3 h of ...
Becoming antibiotic resistant is often associated with fitness costs for the resistant bacteria. This is seen as a loss of competitiveness against the antibiotic-sensitive wild-type in an antibiotic-free environment. In this study, the physiological alterations associated with fitness cost of antibiotic resistance in vitro (in the laboratory medium), and in vivo (in a mouse infection model), are identified in the model system of fusidic acid resistant (FusR) Salmonella enterica serovar Typhimurium.. FusR mutants have mutations in fusA, the gene that encodes translation elongation factor G (EF-G). FusR EF-G has a slow rate of regeneration of active EF-G·GTP off the ribosome, resulting in a slow rate of protein synthesis. The low fitness of FusR mutants in vitro, and in vivo, can be explained in part by a slow rate of protein synthesis and resulting slow growth. However, some FusR mutants with normal rates of protein synthesis still suffer from reduced fitness in vivo. We observed that FusR ...
Methane is metabolized principally by methanotrophs and methanogens in the global carbon cycle. Methanotrophs consume methane as the only source of carbon, while methanogens produce methane as a metabolic byproduct. Methylotrophs, which are microorganisms that can obtain energy for growth by oxidizing one-carbon compounds, such as methanol and methane, are situated between methanotrophs and methanogens. Methanogens can obtain energy for growth by converting a limited number of substrates to methane under anaerobic conditions. Three types of methanogenic pathways are known: CO2 to methane [MD:M00567], methanol to methane [MD:M00356], and acetate to methane [MD:M00357]. Methanogens use 2-mercaptoethanesulfonate (CoM; coenzyme M) as the terminal methyl carrier in methanogenesis and have four enzymes for CoM biosynthesis [MD:M00358]. Coenzyme B-Coenzyme M heterodisulfide reductase (Hdr), requiring for the final reaction steps of methanogenic pathway, is divided into two types: cytoplasmic HdrABC in ...
Salmonella enterica subsp. enterica serovar Typhimurium bacteriophage P22 ATCC ® 19585-B1™ Designation: P22 TypeStrain=False Application: Emerging infectious disease research
Salmonella is the second most frequent cause of foodborne illness in Canada and pork is one of sources for human salmonellosis. Salmonella has also the potential to cause clinical disease in pigs. Salmonella is commonly found on Ontario swine farms. Thus control strategies should be implemented. Vaccination appears to be one of the most promising approaches. In Canada, there is currently available a live Salmonella Choleraesuis vaccine for use in pigs and a live Salmonella Typhimurium vaccine for use in poultry. However, the course of immune responses induced by the above vaccines in 11 pigs is not well studied. The objective of this proposal is to evaluate and compare the immune responses produced by these two Salmonella vaccines in pigs. This research can provide a better understanding of pig immune responses against Salmonella attenuated vaccines and will help to develop new vaccines for controlling Salmonella on Ontario swine farms.. ...
Background: S. Typhi, a human-restricted Salmonella enterica serovar, causes a systemic intracellular infection in humans (typhoid fever). In comparison, S. Typhimurium causes gastroenteritis in humans, but causes a systemic typhoidal illness in mice. The PhoP regulon is a well studied two component (PhoP/Q) coordinately regulated network of genes whose expression is required for intracellular survival of S. enterica. Methodology/Principal Findings: Using high performance liquid chromatography mass spectrometry (HPLC-MS/MS), we examined the protein expression profiles of three sequenced S. enterica strains: S. Typhimurium LT2, S. Typhi CT18, and S. Typhi Ty2 in PhoP-inducing and non-inducing conditions in vitro and compared these results to profiles of \(phoP^−/Q^−\) mutants derived from S. Typhimurium LT2 and S. Typhi Ty2. Our analysis identified 53 proteins in S. Typhimurium LT2 and 56 proteins in S. Typhi that were regulated in a PhoP-dependent manner. As expected, many proteins ...
Abstract: Poultry industry usually exposing birds to a variety of actions and stressors includs fasting for gastrointestinal emptying before transportation and where birds are often exposed to high environmental temperature during the summer months. These environmental stressors may have influences on bird performance and susceptibility to pathogens such as Salmonella enteritidis by altering the intestinal micrbiota and changes in the gut integrity. Approach: This research was conducted to show that acute stressors in the poultry production can induce changes in the normal intestinal microbiota and epithelium structure and execratory functions, which may cause an increase in the opportunities of attachment of Salmonella enteritidis. Results: Experiments were conducted to determine the influence of 24 h feed withdrawal with 24 h exposure to high temperature (30°C) on intestinal characteristics of broilers. Attachment of Salmonella enteritidis to ileal tissue was determined using an in vitro ...
humans, resulting in Being zoonotic, Salmonella enterica subsp. Salmonella pullorum 5. at 37°C and allowed to grow for 18 to 24 hours The LPS is made up of an O-antigen, a polysaccharide core, and lipid A, which connects it to the outer membrane. greater amounts of atmospheric oxygen, and in Remove garments that may have become soiled or contaminated and place them in a double red plastic bag. This pathogen is infamously Immunology, Infection, Rosenberger, C., Scott, Once this is Disease/Infection bluish-green with black centres, indicating that typhimurium, an aerobic bacteria, to to the spleen and liver where it causes Gram-negative Salmonella typhimurium that are produced as a result of engulfment include being lactose negative, citrate Salmonella is a Gram-negative, rod-shaped, motile bacilli which move with the use of its peritrichous flagella.The genus Salmonella can be divided into two species (S. enterica and S. bongori), based on their phenotypic profile.The genus Salmonella is a ...
Part of the ABC transporter complex MalEFGK involved in maltose/maltodextrin import. Responsible for energy coupling to the transport system.
We compared antimicrobial resistance phenotypes and pulsed-field gel electrophoresis (PFGE) subtypes of 1,028 human and 716 animal Salmonella enterica serotype Typhimurium isolates from Minnesota from 1997 to 2003. Overall, 29% of human isolates were multidrug resistant. Predominant phenotypes included resistance to ampicillin, chloramphenicol or kanamycin, streptomycin, sulfisoxazole, and tetracycline (ACSSuT or AKSSuT). Most human multidrug-resistant isolates belonged to PFGE clonal group A, characterized by ACSSuT resistance (64%), or clonal group B, characterized by AKSSuT resistance (19%). Most animal isolates were from cattle (n = 358) or swine (n = 251). Eighty-one percent were multidrug resistant; of these, 54% were at least resistance phenotype ACSSuT, and 43% were at least AKSSuT. More than 80% of multidrug-resistant isolates had a clonal group A or B subtype. Resistance to ceftriaxone and nalidixic acid increased, primarily among clonal group A/ACSSuT isolates. Clonal group B/AKSSuT ...
Effect of Low Dose γ-Irradiation on the Fate and Cell Envelope of Bacillus cereus, Escherichia coli, and Salmonella Typhimurium - ${\gamma}$-irradiation;cell envelop damage;antibiotic resistance;Bacillus cereus;Escherichia coli;Salmonella Typhimurium;
Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104, resistant to ampicillin, chloramphenicol/florfenicol, streptomycin, sulfonamides, and tetracycline, has disseminated worldwide. The resistance genes reside on the 43-kb Salmonella genomic island 1 (SGI1), which is transferable. Drug-resistant variants of SGI1 have been identified in numerous serotypes. Strains harboring SGI1 may be more virulent and have a tendency to rapidly disseminate.
Many dogs and cats naturally carry Salmonella (mostly Salmonella typhimurium) in their digestive tracts. The report states that studies have found a 1-15% prevalence of Salmonella in the faeces of healthy dogs, and 1-18% in healthy cats.. According to the report, Salmonella is the most common food-borne bacteria. Around 1.4 million people in the U.S. contract Salmonella infections each year. About 1,000 of these die. About half of all Salmonella infections are from restaurants; and are often traced to infected, but asymptomatic, food handlers. Many of us have Salmonella infections and feel no ill effects. Meat, poultry, eggs, milk, fruits and vegetables can be contaminated with Salmonella. Processed foods can be easily infected in a contaminated plant. Recent food recalls for Salmonella have involved nuts, chocolate bars, peppers, and peanut butter. SALMONELLA INFECTION DOES NOT ALWAYS CAUSE ILL-HEALTH. MANY CARRIERS OF SALMONELLA SHOW NO SYMPTOMS OF DISEASE. ...
TY - JOUR. T1 - Efficacy of Salmonella typhimurium A1-R versus chemotherapy on a pancreatic cancer patient-derived orthotopic xenograft (PDOX). AU - Hiroshima, Yukihiko. AU - Zhao, Ming. AU - Maawy, Ali. AU - Zhang, Yong. AU - Katz, Matthew H.G.. AU - Fleming, Jason B.. AU - Uehara, Fuminari. AU - Miwa, Shinji. AU - Yano, Shuya. AU - Momiyama, Masashi. AU - Suetsugu, Atsushi. AU - Chishima, Takashi. AU - Tanaka, Kuniya. AU - Bouvet, Michael. AU - Endo, Itaru. AU - Hoffman, Robert M.. N1 - Copyright: Copyright 2016 Elsevier B.V., All rights reserved.. PY - 2014/7. Y1 - 2014/7. N2 - The aim of this study is to determine the efficacy of tumor-targeting Salmonella typhimurium A1-R (A1-R) on pancreatic cancer patient-derived orthotopic xenografts (PDOX). The PDOX model was originally established from a pancreatic cancer patient in SCID-NOD mice. The pancreatic cancer PDOX was subsequently transplanted by surgical orthotopic implantation (SOI) in transgenic nude red fluorescent protein (RFP) mice in ...
The GeneChip Porcine Genome Array was used to identify the transcriptional response upon either Salmonella typhimurium (ST) or Salmonella choleraesuis (SC) infection in two porcine epithelial cell lines (IPEC-J2, from jejunum and IPI-2I, from ileum) during 2 and 4 hours post infection. The objectives in this study were first, to identify the different response between the epithelial cell lines from different gut regions; second, to study how the Salmonella serotypes used could elicit a different host response; and third, to determine the effect of the time-points on the differentially gene expression. Overall design: Epithelial cells were seeded into 6-well tissue culture plates and grown to confluence in 5% CO2 at 37ºC. Monolayers were infected for 1 h. with Salmonella typhimurium or Salmonella choleraesuis serotypes (MOI 1:10) or incubated with media alone (Control cells). Extracellular bacteria were removed, and cultures were further incubated during 2 and 4 h. in the presence of 50 µg/ml of the
Although, haemolysis was also observed on blood agar prepared with whole blood, clarity of zone was more evident on blood agar made from washed erythrocytes. The local public health department confirmed the organism to be Salmonella enterica subspecies enterica â ¦ Representative dataare given in figure 4. The Salmonella are facultative anaerobic Gram-negative bacilli, motile, nonâ capsulated, non-sporing organism.Salmonella currently comprises of about 2,500 serotypes or species. microorganisms Article Validating Thermal Lethality to Salmonella enterica in Chicken Blood by Simulated Commercial Rendering Caleb Wong de la Rosa 1, Kourtney A. Daniels 2, Rosana G. â ¦ Severe pediatric malaria is an important risk factor for developing disseminated infections with nontyphoidal Salmonella serotypes (NTS). Incubate plates 24 ± 2 h at 35°C. Clear zone haemolysis was best observed on blood agar â ¦ Adaptation of the Endogenous Salmonella enterica Serovar Typhi clyA-Encoded Hemolysin for ... ...
We report the genome sequence of a monophasic Salmonella enterica subsp. enterica Typhimurium strain (TW-Stm6) isolated in Australia that is similar to epidemic multidrug-resistant strains from Europe and elsewhere. This strain carries additional antibiotic and heavy-metal resistance genes on a large (275-kb) IncHI2 plasmid ...
Non-typhoidal Salmonella is an important bacterial pathogen causing worldwide morbidity and mortality. Early interactions between Salmonella Typhimurium and intestinal epithelium have been demonstrated in animal models, but little is known in humans. After HEp-2 cell infection and extraction of genomic DNA using 1,440 transposon mutants of Salmonella Typhimurium, Transposon Directed Insertion-site Sequencing (TraDIS) identified 6 novel Salmonella virulence genomic loci responsible for adhesion/invasion (intergenic sucD-cydA, glyA, yqiC, wzxE, and rfaI) and intracellular replication (speG). The aims of this project were to a) create the single-gene mutants by site-directed mutagenesis, b) characterize the discovered genes by testing the created mutants in the established in vitro human epithelial cells (e.g. HEp-2 cells, polarized Caco-2 cells, and LS174T cells) and polarized human intestinal ex vivo organ culture models to study Salmonella virulence (bacterial adhesion, invasion, and ...
Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1 and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S. Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S. Typhimurium was converted into O9, O7 and O8 serotypes through unmarked chromosomal deletion-insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion
1.Cheng, S., et al., Bacterial microcompartments: their properties and paradoxes. Bioessays, 2008. 30(11-12): p. 1084-95. 2.Yeates, T.O., et al., Protein-based organelles in bacteria: carboxysomes and related microcompartments. Nat Rev Microbiol, 2008. 6(9): p. 681-91. 3.Shively, J.M., Inclusion bodies of prokaryotes. Annu Rev Microbiol, 1974. 28(0): p. 167-87. 4.Chen, P., D.I. Andersson, and J.R. Roth, The control region of the pdu/cob regulon in Salmonella typhimurium. J Bacteriol, 1994. 176(17): p. 5474-82. 5.Havemann, G.D., E.M. Sampson, and T.A. Bobik, PduA is a shell protein of polyhedral organelles involved in coenzyme B(12)-dependent degradation of 1,2-propanediol in Salmonella enterica serovar typhimurium LT2. J Bacteriol, 2002. 184(5): p. 1253-61. 6.Brinsmade, S.R., T. Paldon, and J.C. Escalante-Semerena, Minimal functions and physiological conditions required for growth of salmonella enterica on ethanolamine in the absence of the metabolosome. J Bacteriol, 2005. 187(23): p. 8039-46. ...
In Rio Grande do Sul (RS) State, Southern Brazil, a clonal group of Salmonella Enteritidis has been identified as the main cause of foodborne diseases, in the last years. Given that, the objective of this study was to evaluate the survival in simulated gastric fluid (FGS) and the intestinal invasion ability of Salmonella Enteritidis (SE86) and Salmonella Typhimurium (ST99) submitted or not to acid adaptation. The microorganisms were grown in culture media and culture media supplemented with glucose, aiming to promote acid adaptation. After that, approximately 9log of SE86 (Isolated from a foodborne outbreak) and ST99 (not involved with foodborne outbreaks), acid-adapted or not adapted, were exposed to FGS with pH 1.5, and inoculated in adult male Wistar rats. Germ-free mice were also inoculated but with approximately 2 log, and the animals were observed during 21 days, at aseptic conditions. Animal feces and portions of the gastrointestinal tract were examined by microbiological analysis, and ...
The extensive medical and agricultural use and misuse of antibiotics during the last 70 years has caused an enrichment of resistant pathogenic bacteria that now severely threatens our capacity to efficiently treat bacterial infections. While is has been known for a long time that high concentrations of antibiotics can select for resistant mutants, less is known about the lower limit at which antibiotics can be selective and enrich for resistant bacteria.. In this thesis we investigated the role of low concentrations of antibiotics and heavy metals in the enrichment and evolution of antibiotic resistance. Selection was studied using Escherichia coli and Salmonella enterica serovar Typhimurium LT2 with different resistance mutations, different chromosomal resistance genes as well as large conjugative multidrug resistance plasmids. Using very sensitive competition experiments, we showed that antibiotic and heavy metal levels more than several hundred-fold below the minimal inhibitory concentration ...
Deficiency of a modified nucleoside in tRNA often mediates suppression of +1 frameshift mutations. In Salmonella enterica serovar Typhimurium strain TR970 (hisC3737), which requires histidine for growth, a potential +1 frameshifting site, CCC-CAA-UAA, exists within the frameshifting window created by insertion of a C in the hisC gene. This site may be suppressed by peptidyl-tRNAProcmo5UGG (cmo(5)U is uridine-5-oxyacetic acid), making a frameshift when decoding the near-cognate codon CCC, provided that a pause occurs by, e.g., a slow entry of the tRNAGlnmnm5s2UUG (mnm(5)s(2)U is 5-methylaminomethyl-2-thiouridine) to the CAA codon located in the A site. We selected mutants of strain TR970 that were able to grow without histidine, and one such mutant (iscS51) was shown to have an amino acid substitution in the L-cysteine desulfurase IscS. Moreover, the levels of all five thiolated nucleosides 2-thiocytidine, mnm(5)s(2)U, 5-carboxymethylaminomethyl-2-thiouridine, 4-thiouridine, and ...
The flagellar systems of Escherichia coli and Salmonella enterica exhibit a significant level of genetic and functional synteny. Both systems are controlled by the flagellar specific master regulator FlhD4C2. Since the early days of genetic analyses of flagellar systems it has been known that E. coli flhDC can complement a ∆flhDC mutant in S. enterica. The genomic revolution has identified how genetic changes to transcription factors and/or DNA binding sites can impact the phenotypic outcome across related species. We were therefore interested in asking: using modern tools to interrogate flagellar gene expression and assembly, what would the impact be of replacing the flhDC coding sequences in S. enterica for the E. coli genes at the flhDC S. entercia chromosomal locus? We show that even though all strains created are motile, flagellar gene expression is measurably lower when flhDCEC are present. These changes can be attributed to the impact of FlhD4C2 DNA recognition and the protein-protein ...
Phylogenetic diversity of the enteric pathogen Salmonella enterica subsp. enterica inferred from genome-wide reference-free SNP characters ...
The first priority in case of a Salmonella contamination it to trace the source as soon as possible. To facilitate an efficient search it is good to know that different sources of Salmonella contamination are often associated with distinct Salmonella serotypes. Therefore, it is essential in any Salmonella reduction program to know which serotype is the culprit. The traditional Kauffmann-White method for confirming and serotyping Salmonella takes at least several days to obtain an end result. Also, up to 10 - 15% of cases yield inconclusive results. This is why Check-Points developed Check & Trace Salmonella, which overcomes these hurdles. It provides a rapid Salmonella confirmation and serotyping method based on DNA technology for routine use in any laboratory. With a single test - which can be performed in one day - it confirms the presence of Salmonella and identifies the serotype. If you suspect a Salmonella contamination in your poultry farm, Check & Trace Salmonella is the fastest and most ...
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Salmonella caused by an infectious agent (pathogen) that is called Salmonella enteriditis. The bacteria is larger than a virus; but, is visible with a microscope. It is a microscopic living creature that passes from the feces of people or animals to others. It has been causing illnesses for over 100 years. It infects the cell, multiples within it then bursts the cell. Special effect protein factors are required for salmonella intestinal invasion and the induction of fluid secretion and inflammatory responses. Salmonella is most common in birds, mainly poultry. Newborn calves are also susceptible to the bacteria. The feces from the dam could get in the mouth of the calf after being born. Salmonella enteritidis and Salmonella enteric are which causes human disease. Salmonellosis spreads to people by ingestion of Salmonella bacteria that is from contaminated food. Salmonella is worldwide and can contaminate almost any food type, but outbreaks of the disease have highly involved raw eggs, raw meat, ...
1. Taylor J, McCoy JH. Salmonella and Arizonae infections and intoxications. In Riemann, H (ed.) Foodborne Infections and Intoxications. Academic Press:New York, New York. 1969;3-72.. 2. Bean NH, Griffin PM. Foodborne disease outbreaks in the United States 1973-1987: pathogens, vehicles and trends. J Food Prot. 1990; 53:804-817.. 3. Lammerding AM, Garcia MM, Mann ED, Robinson Y, Dorward WJ, Truscott RB, Tittiger F. 1988. Prevalence of Salmonella and thermophilic Campylobacter in fresh pork, beef, veal and poultry in Canada. J Food Prot. 1988; 51:47-52.. 4. Buchwald DS, Blaser MJ. A review of human salmonellosis. II. Duration of excretion following infection and nontyphi Salmonella. Rev Infect Dis. 1984; 6:345-356.. 5. Kotova AL, Kondratskaya SA, Yasutis IM. 1988. Salmonella carrier state and biological characteristics of the infectious agent. J Hyg Epidemiol Microbiol Immunol. 1988; 32:71-78.. 6. Wood RL, Pospischil A, Rose R. 1989. Distribution of persistent Salmonella typhimurium infection in ...
For several years, the resistance of Salmonella enterica to expanded-spectrum cephalosporins has been increasingly reported, as has the diversity of β-lactamases involved in this resistance. Using a chronological approach, we can assume that the extended-spectrum β-lactamases observed between 1985 and 1990 concerned SHV and TEM derivatives (1, 9) whereas those described since 1990 concerned not only new class A β-lactamases, such as CTX-M type and PER enzymes (2, 4, 15), but also plasmid-mediated class C β-lactamases, namely DHA-1 (8) and CMY-2 (7, 13). Fortunately, all these plasmid-mediated class A and class C β-lactamases do not confer imipenem (IMI) resistance to the isolates. However, as presented in this paper, the association of different mechanisms of resistance led to IMI resistance in one of the two multidrug-resistant isolates of Salmonella enterica serovar Wien which were recently found in Tunis.. The two isolates (SW468 and SW1107) came from the blood of two neonates ...
Salmonella enterica subsp. enterica serovar Muenchen ATCC ® BAA-1676D-5™ Designation: Genomic DNA from Salmonella enterica subsp. enterica serovar Muenchen strain MZ1478 TypeStrain=False Application:
Many environmental signals are known to stimulate or repress expression of the Salmonella invasion regulon (for a review see Lucas and Lee, 2000). These signals are transduced by an unknown mechanism to HilA, which then directly activates invF (Lostroh et al., 2000). In this study, we examined the role of InvF and SicA in the regulation of a specific subset of invasion genes encoding secreted effector proteins and their cognate chaperones. A consensus sequence, the InvF binding site, was identified in three chromosomally unlinked invasion loci. The sicA promoter controls the expression of the sicAsip/sspBCDA and, most likely, the sicPsptP genes. Sip/SspB and C have been shown to be required for the translocation of several other proteins, including SigD, SopE, and SptP (Wood et al., 1996; Collazo and Galán, 1997; Galyov et al., 1997; Fu and Galán, 1998b). SipB has been assigned several functions from effector translocator to stimulator of bacterial induced apoptosis (Kaniga et al., 1995b; ...
Abstract Aims: The purpose of this study is to investigate the efficacy of continuous ohmic heating for reducing Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ...
Salmonella are ubiquitous enteric bacteria, responsible for thousands of deaths world-wide.. In this book, the authors present current research in the study of the classification, genetics and disease outbreak cases relating to salmonella.. Topics include the pre- and post-harvest intervention strategies for controlling salmonella contamination in broiler production; salmonella enterica survival to biocides and antibiotics; salmonella new-port contamination in produce; genome comparisons of salmonella; salmonella in sub-Antarctica and Antarctica; and hazard of salmonella in the intact shell egg. ...
TY - JOUR. T1 - Tumor targeting Salmonella typhimurium A1-R in combination with gemcitabine (GEM) regresses partially GEM-resistant pancreatic cancer patient-derived orthotopic xenograft (PDOX) nude mouse models. AU - Kawaguchi, Kei. AU - Miyake, Kentaro. AU - Zhao, Ming. AU - Kiyuna, Tasuku. AU - Igarashi, Kentaro. AU - Miyake, Masuyo. AU - Higuchi, Takashi. AU - Oshiro, Hiromichi. AU - Bouvet, Michael. AU - Unno, Michiaki. AU - Hoffman, Robert M.. N1 - Publisher Copyright: © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.. PY - 2018/8/18. Y1 - 2018/8/18. N2 - Gemcitabine (GEM) is first-line therapy for pancreatic cancer but has limited efficacy in most cases. Nanoparticle-albumin bound (nab)-paclitaxel is becoming first-line therapy for pancreatic cancer, but also has limited efficacy for pancreatic cancer. Our goal was to improve the treatment outcome in patient-like models of pancreatic cancer. We previously established patient-derived orthotopic xenografts (PDOX) ...
Salmonella enterica Typhimurium DT104 is a major strain of Salmonella linked with food-borne illness and a significant concern to the beef industry. DT104 strains are often multiply drug-resistant and are easily spread in the close parameters of beef cattle ranches. A toxin found on the genome of DT104 strains, called artAB, has homology to other well characterized bacterial toxins. The goal of this study is to find an efficient way of genotyping and identifying the artAB toxin in bovine Salmonella isolates. The primary method used is Multiplex Polymerase Chain Reaction (MPCR), which allows for simultaneous PCR of multiple genes. We obtained four sets of primers to identify Salmonella species, phage type and artAB. In separate trials using 8 agricultural Salmonella samples we have found that the MPCR program is effective and will work for continued genotyping. ArtAB has thus far been found in 3 of 8 samples and correlates well with DT104. This work will help to define the importance of artAB in bovine
The aim of this research was to evaluate the risk of inoculated Salmonella persisting on the outside of the shell of hens eggs. Hens eggs were surface inoculated with a cocktail of Salmonella strains and stored for up to 54 days at 4, 10 and 20 °C and at 80 and 90% relative humidity. Salmonella survival showed an irregular pattern, with extremes of high recovery and no recovery. However, salmonellae were always recovered after resuscitation. Monte Carlo simulation of different scenarios using relevant assumptions indicated that the distribution of surviving Salmonella was skewed towards low numbers, suggesting higher chances of Salmonella persisting on the eggs in low numbers (,104 cfu egg−1). Although numbers were low, the research demonstrated the ability of salmonellae to survive on the shells of eggs following contamination and this clearly has safety implications for handling of eggs in the food industry and the domestic environment. ...
Infections and inflammation can lead to cachexia and wasting of skeletal muscle and fat tissue by as yet poorly understood mechanisms. We observed that gut colonization of mice by a strain of Escherichia coli prevents wasting triggered by infections or physical damage to the intestine. During intestinal infection with the pathogen Salmonella Typhimurium or pneumonic infection with Burkholderia thailandensis, the presence of this E. coli did not alter changes in host metabolism, caloric uptake, or inflammation but instead sustained signaling of the insulin-like growth factor 1/phosphatidylinositol 3-kinase/AKT pathway in skeletal muscle, which is required for prevention of muscle wasting. This effect was dependent on engagement of the NLRC4 inflammasome. Therefore, this commensal promotes tolerance to diverse diseases. ...