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Dunstan, Sarah J., Cameron P. Simmons, and Richard A. Strugnell. "Use of In Vivo-Regulated Promoters To Deliver Antigens from Attenuated Salmonella enterica var. Typhimurium." Infection and Immunity 67, no. 10 (October 1, 1999): 5133–41. http://dx.doi.org/10.1128/iai.67.10.5133-5141.1999.
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ABSTRACT This study describes the construction and analysis of three in vivo-inducible promoter expression plasmids, containing pnirB, ppagC, and pkatG, for the delivery of foreign antigens in the ΔaroAD mutant ofSalmonella enterica var. Typhimurium (hereafter referred to as S. typhimurium). The reporter genes encoding β-galactosidase and firefly luciferase were used to assess the comparative levels of promoter activity in S. typhimuriumin vitro in response to different induction stimuli and in vivo in immunized mice. It was determined that the ppagC construct directed the expression of more β-galactosidase and luciferase inS. typhimurium than the pnirB and pkatG constructs, both in vitro and in vivo. The gene encoding the C fragment of tetanus toxin was expressed in thearoAD mutant of S. typhimurium (BRD509) under the control of the three promoters. Mice orally immunized with attenuated S. typhimurium expressing C fragment under control of the pagC promoter [BRD509(pKK/ppagC/C frag)] mounted the highest tetanus toxoid-specific serum antibody response. Levels of luciferase expression in vivo and C-fragment expression in vitro from thepagC promoter appeared to be equivalent to if not lower than the levels of expression detected with the constitutivetrc promoter. However, mice immunized with BRD509(pKK/ppagC/C frag) induced significantly higher levels of tetanus toxoid-specific antibody than BRD509(pKK/C frag)-immunized mice, suggesting that the specific location of foreign antigen expression may be important for immunogenicity. Mutagenesis of the ribosome binding sites (RBS) in the three promoter/C fragment expression plasmids was also performed. Despite optimization of the RBS in the three different promoter elements, the expression levels in vivo and overall immunogenicity of C fragment when delivered to mice by attenuated S. typhimurium were not affected. These studies suggest that in vivo-inducible promoters may give rise to enhanced immunogenicity and increase the efficacy of S. typhimuriumas a vaccine vector.
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Goh, Yun Shan, Simon Clare, Francesca Micoli, Allan Saul, Pietro Mastroeni, and Calman A. MacLennan. "Monoclonal Antibodies of a Diverse Isotype Induced by an O-Antigen Glycoconjugate Vaccine MediateIn VitroandIn VivoKilling of African Invasive Nontyphoidal Salmonella." Infection and Immunity 83, no. 9 (July 13, 2015): 3722–31. http://dx.doi.org/10.1128/iai.00547-15.
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NontyphoidalSalmonella(NTS), particularlySalmonella entericaserovars Typhimurium and Enteritidis, is responsible for a major global burden of invasive disease with high associated case-fatality rates. We recently reported the development of a candidate O-antigen–CRM197glycoconjugate vaccine againstS.Typhimurium. Here, using a panel of mouse monoclonal antibodies generated by the vaccine, we examined the relative efficiency of different antibody isotypes specific for the O:4 antigen ofS. Typhimurium to effectin vitroandin vivokilling of the invasive AfricanS. Typhimurium strain D23580. All O:4-specific antibody isotypes could mediate cell-free killing and phagocytosis ofS. Typhimurium by mouse blood cells. Opsonization ofSalmonellawith O:4-specific IgA, IgG1, IgG2a, and IgG2b, but not IgM, resulted in cell-dependent bacterial killing. At high concentrations, O:4-specific antibodies inhibited both cell-free complement-mediated and cell-dependent opsonophagocytic killing ofS. Typhimuriumin vitro. Using passive immunization in mice, the O:4-specific antibodies providedin vivofunctional activity by decreasing the bacterial load in the blood and tissues, with IgG2a and IgG2b being the most effective isotypes. In conclusion, an O-antigen–CRM197glycoconjugate vaccine can induce O-antigen-specific antibodies of different isotypes that exertin vitroandin vivokilling ofS. Typhimurium.
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Abd El Ghany, Moataz, Angela Jansen, Simon Clare, Lindsay Hall, Derek Pickard, Robert A. Kingsley, and Gordon Dougan. "Candidate Live, Attenuated Salmonella enterica Serotype Typhimurium Vaccines with Reduced Fecal Shedding Are Immunogenic and Effective Oral Vaccines." Infection and Immunity 75, no. 4 (February 12, 2007): 1835–42. http://dx.doi.org/10.1128/iai.01655-06.
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ABSTRACT Environmental shedding of genetically manipulated microorganisms is an issue impeding the development of new live vaccines. We have investigated the immunogenicity of a number of novel Salmonella enterica serotype Typhimurium oral vaccine candidates that express the fragment C (TetC) component of tetanus toxin and harbor combinations of additional mutations in genes shdA, misL, and ratB that contribute to the persistence of serotype Typhimurium's colonization of the intestine. Serotype Typhimurium aroA (TetC) derivatives harboring additional mutations in either shdA or misL or combinations of these mutations exhibited a marked decrease in shedding of the vaccine strain in the feces of orally vaccinated mice. However, equivalent levels of anti-TetC and anti-Salmonella lipopolysaccharide immunoglobulin G (IgG), IgG1, IgG2a, and IgA were detected in sera of the vaccinated but not of the control mice. Cellular immune responses to TetC were detected in all vaccinated mice, regardless of the presence of the additional mutations in shdA or misL. Further, immunization with serotype Typhimurium aroA candidate vaccines harboring shdA and misL afforded complete protection against challenge with a virulent strain of serotype Typhimurium.
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AL-kafaji, Narjis Amer, Zainab R. Zghair, and MethaqGhlibAbd AL-Rubaie. "Pathological study of alcoholic plant agolanceolata crude extracts effect on some Salmonella species invitro and in vivo." Kufa Journal For Veterinary Medical Sciences 7, no. 1B (October 10, 2016): 109–16. http://dx.doi.org/10.36326/kjvs/2016/v7i1b4272.
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This study was designed to explore the pathological effect of alcoholic plant agolanceolata crude extracts effect on some Salmonella species invitro and in vivo study by using laboratory mice .plant agolanceolata crude extract were dealing in vitro study against some virulent bacteria including Salmonella typhimurium ,Salmonella typhiond Salmonella hadar. And using the concentrations (100,150,200,250 and 300) mg for plan tagolanceolata crude extract ,concentration at 300 mg and the highest inhibitory effect on the three types of salmonella ,when compared with the other concentrations .The pathological study of plant agolanceolata crude extract was done against the infection of Salmonella typhimurium as in vivo study by using white laboratory mice. Twenty four mice were randomly divided into six groups, each group contain four animals. First group was administrated orally o.3 ml of Salmonella typhimuriumof bacterial suspension containing 1x106cfu orally for one week of infection. Second group administrated orally with 0.3 ml of bacterial suspension containing 1x106cfu orally of Salmonella typhimurium for two weeks as infection. Third group administrated orally with 0.3 ml of bacterial suspension containing 1x106cfu orally Salmonella typhimurium for three weeks as infection. Fourth group was administrated orally with o.3 ml of plant agolanceolata extract for one week daily after infection with Salmonella typhimurium. Fifth group was administrated orally with o.3 ml of plant agolanceolata extract for two weeks daily after infection with Salmonella typhimurium. And sixth group was administrated orally with o.3 ml of plant agolanceolata extract for three weeks daily after infection with Salmonella typhimurium. The histopathological study showed pathological changes in theintestine of the first , second and third groups that infected with Salmonella typhimuriumbacteria, (sixfhgroup)no clear pathological changes were reported except some lesions. For all, the plantagolanceolata extract apparently has therapeutic effect whenused in high concentration invitro and for long time invivo.
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Everest, Paul, Julian Ketley, Simon Hardy, Gill Douce, Shahid Khan, Jacqui Shea, David Holden, Duncan Maskell, and Gordon Dougan. "Evaluation of Salmonella typhimuriumMutants in a Model of Experimental Gastroenteritis." Infection and Immunity 67, no. 6 (June 1, 1999): 2815–21. http://dx.doi.org/10.1128/iai.67.6.2815-2821.1999.
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ABSTRACT Salmonella typhimurium strains harboring independent, defined mutations in aroA, invA,ssrA, or msbB were assessed for their ability to induce fluid accumulation, tissue damage, and local inflammation in rabbit ileal loops. Three wild-type strains of S. typhimurium, TML, HWSH, and SL1344, and two mutant strains,S. typhimurium SL1344 ssrA and S. typhimurium SL1344 msbB, consistently induced fluid accumulation in the lumen of loops and inflammation of loop-associated tissues. In contrast, three different S. typhimurium aroAstrains and an invA mutant of SL1344 did not induce significant fluid accumulation in the rabbit ileal loops. However, theS. typhimurium aroA strains did induce an inflammatory infiltrate and some local villus-associated damage, but theinvA mutant did not. Histologically, wild-type S. typhimurium, S. typhimurium SL1344 ssrA, and S. typhimurium SL1344 msbB demonstrated more severe effects on villus architecture than S. typhimurium aroA strains, whereas S. typhimurium invA-infected loops showed no detectable damage. This suggests that villus damage most likely contributes to fluid accumulation within the loop.
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Voedisch, Sabrina, Christian Koenecke, Sascha David, Heike Herbrand, Reinhold Förster, Mikael Rhen, and Oliver Pabst. "Mesenteric Lymph Nodes Confine Dendritic Cell-Mediated Dissemination of Salmonella enterica Serovar Typhimurium and Limit Systemic Disease in Mice." Infection and Immunity 77, no. 8 (June 8, 2009): 3170–80. http://dx.doi.org/10.1128/iai.00272-09.
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ABSTRACT In humans with typhoid fever or in mouse strains susceptible to Salmonella enterica serovar Typhimurium (S. Typhimurium) infection, bacteria gain access to extraintestinal tissues, causing severe systemic disease. Here we show that in the gut-draining mesenteric lymph nodes (MLN), the majority of S. Typhimurium-carrying cells show dendritic-cell (DC) morphology and express the DC marker CD11c, indicating that S. Typhimurium bacteria are transported to the MLN by migratory DCs. In vivo FLT-3L-induced expansion of DCs, as well as stimulation of DC migration by Toll-like receptor agonists, results in increased numbers of S. Typhimurium bacteria reaching the MLN. Conversely, genetically impaired DC migration in chemokine receptor CCR7-deficient mice reduces the number of S. Typhimurium bacteria reaching the MLN. This indicates that transport of S. Typhimurium from the intestine into the MLN is limited by the number of migratory DCs carrying S. Typhimurium bacteria. In contrast, modulation of DC migration does not affect the number of S. Typhimurium bacteria reaching systemic tissues, indicating that DC-bound transport of S. Typhimurium does not substantially contribute to systemic S. Typhimurium infection. Surgical removal of the MLN results in increased numbers of S. Typhimurium bacteria reaching systemic sites early after infection, thereby rendering otherwise resistant mice susceptible to fatal systemic disease development. This suggests that the MLN provide a vital barrier shielding systemic compartments from DC-mediated dissemination of S. Typhimurium. Thus, confinement of S. Typhimurium in gut-associated lymphoid tissue and MLN delays massive extraintestinal dissemination and at the same time allows for the establishment of protective adaptive immune responses.
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Gao, Yuan, Kaifeng Chen, Runshan Lin, Xuebin Xu, Fengxiang Xu, Qijie Lin, Yaping Hu, et al. "High Levels of Antibiotic Resistance in MDR-Strong Biofilm-Forming Salmonella Typhimurium ST34 in Southern China." Microorganisms 11, no. 8 (August 3, 2023): 2005. http://dx.doi.org/10.3390/microorganisms11082005.
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Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium) is an important zoonotic pathogen with important public health significance. To understand S. typhimurium’s epidemiological characteristics in China, multi-locus sequence typing, biofilm-forming ability, antimicrobial susceptibility testing, and resistant genes of isolates from different regions and sources (human, food) were investigated. Among them, ST34 accounted for 82.4% (243/295), with ST19 ranking second (15.9%; 47/295). ST34 exhibited higher resistance levels than ST19 (p < 0.05). All colistin, carbapenem, and ciprofloxacin-resistant strains were ST34, as were most cephalosporin-resistant strains (88.9%; 32/36). Overall, 91.4% (222/243) ST34 isolates were shown to have multidrug resistance (MDR), while 53.2% (25/47) ST19 isolates were (p < 0.05). Notably, 97.8% (45/46) of the MDR-ACSSuT (resistance to Ampicillin, Chloramphenicol, Streptomycin, Sulfamethoxazole, and Tetracycline) isolates were ST34, among which 69.6% (32/46) of ST34 isolates were of human origin, while 30.4% (14/46) were derived from food (p < 0.05). Moreover, 88.48% (215/243) ST34 showed moderate to strong biofilm-forming ability compared with 10.9% (5/46) ST19 isolates (p < 0.01). This study revealed the emergence of high-level antibiotic resistance S. typhimurium ST34 with strong biofilm-forming ability, posing concerns for public health safety.
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Farn, Jacinta, and Mark Roberts. "Effect of Inactivation of the HtrA-Like Serine Protease DegQ on the Virulence of Salmonella enterica Serovar Typhimurium in Mice." Infection and Immunity 72, no. 12 (December 2004): 7357–59. http://dx.doi.org/10.1128/iai.72.12.7357-7359.2004.
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ABSTRACT DegQ is a serine protease that is highly homologous to HtrA, an important virulence determinant of Salmonella enterica serovar Typhimurium. We examined if DegQ is involved in serovar Typhimurium pathogenesis. A serovar Typhimurium degQ mutant was as virulent as the wild-type strain in mice. However, a serovar Typhimurium htrA degQ mutant survived less well in murine organs, particularly in the liver, than a serovar Typhimurium htrA mutant. DegQ is not essential for serovar Typhimurium pathogenesis but may play a small role during salmonella growth at systemic sites.
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Luk, Chak Hon, Camila Valenzuela, Magdalena Gil, Léa Swistak, Perrine Bomme, Yuen-Yan Chang, Adeline Mallet, and Jost Enninga. "Salmonella enters a dormant state within human epithelial cells for persistent infection." PLOS Pathogens 17, no. 4 (April 30, 2021): e1009550. http://dx.doi.org/10.1371/journal.ppat.1009550.
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Salmonella Typhimurium (S. Typhimurium) is an enteric bacterium capable of invading a wide range of hosts, including rodents and humans. It targets different host cell types showing different intracellular lifestyles. S. Typhimurium colonizes different intracellular niches and is able to either actively divide at various rates or remain dormant to persist. A comprehensive tool to determine these distinct S. Typhimurium lifestyles remains lacking. Here we developed a novel fluorescent reporter, Salmonella INtracellular Analyzer (SINA), compatible for fluorescence microscopy and flow cytometry in single-bacterium level quantification. This identified a S. Typhimurium subpopulation in infected epithelial cells that exhibits a unique phenotype in comparison to the previously documented vacuolar or cytosolic S. Typhimurium. This subpopulation entered a dormant state in a vesicular compartment distinct from the conventional Salmonella-containing vacuoles (SCV) as well as the previously reported niche of dormant S. Typhimurium in macrophages. The dormant S. Typhimurium inside enterocytes were viable and expressed Salmonella Pathogenicity Island 2 (SPI-2) virulence factors at later time points. We found that the formation of these dormant S. Typhimurium is not triggered by the loss of SPI-2 effector secretion but it is regulated by (p)ppGpp-mediated stringent response through RelA and SpoT. We predict that intraepithelial dormant S. Typhimurium represents an important pathogen niche and provides an alternative strategy for S. Typhimurium pathogenicity and its persistence.
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Torres, AnnMarie, Amy Kullas, and Adrianus van der Velden. "Characterization of the mechanism by which L-asparaginase II of Salmonella enterica serovar Typhimurium induces T cell inhibition (99.12)." Journal of Immunology 186, no. 1_Supplement (April 1, 2011): 99.12. http://dx.doi.org/10.4049/jimmunol.186.supp.99.12.
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Abstract T cells play a key role in controlling and clearing infection with the bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium). However, T cell-mediated immunity against S. Typhimurium takes months to develop and has been described as slow and inefficient. Previously, we have shown that S. Typhimurium have a direct inhibitory effect on T cells, down-modulating expression of the beta chain of the T cell receptor (TCR-beta) and inhibiting T cell proliferation. Furthermore, we have shown that a soluble, proteinaceous factor produced or induced by S. Typhimurium is responsible for this inhibition. Most recently, we have found that STM3106 is required for S. Typhimurium to inhibit T cells and that L-asparaginase II, which is encoded by STM3106, is present in the supernatants of T cells cultured in the presence of S. Typhimurium. In addition, we have found that L-asparaginase II produced by S. Typhimurium is both necessary and sufficient for the inhibition of T cells. With further characterization, this research should provide new insight into the mechanism by which S. Typhimurium inhibit T cells, avoiding immune clearance.
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Esteves, Cristina L. C., Bradley D. Jones, and Steven Clegg. "Biofilm Formation by Salmonella enterica Serovar Typhimurium and Escherichia coli on Epithelial Cells following Mixed Inoculations." Infection and Immunity 73, no. 8 (August 2005): 5198–203. http://dx.doi.org/10.1128/iai.73.8.5198-5203.2005.
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ABSTRACT Biofilms were formed by inoculations of Salmonella enterica serovar Typhimurium and Escherichia coli on HEp-2 cells. Inoculations of S. enterica serovar Typhimurium and E. coli resulted in the formation of an extensive biofilm of S. enterica serovar Typhimurium. In experiments where an E. coli biofilm was first formed followed by challenge with S. enterica serovar Typhimurium, there was significant biofilm formation by S. enterica serovar Typhimurium. The results of this study indicate that S. enterica serovar Typhimurium can outgrow E. coli in heterologous infections and displace E. coli when it forms a biofilm on HEp-2 cells.
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Langermans, J. A., M. E. van der Hulst, P. H. Nibbering, and R. van Furth. "Activation of mouse peritoneal macrophages during infection with Salmonella typhimurium does not result in enhanced intracellular killing." Journal of Immunology 144, no. 11 (June 1, 1990): 4340–46. http://dx.doi.org/10.4049/jimmunol.144.11.4340.
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Abstract Our study was performed to investigate whether macrophages become activated during an infection with Salmonella typhimurium and, if so, whether these activated macrophages kill S. typhimurium faster than resident macrophages. Mice received i.v. injections with a sublethal number of S. typhimurium; on about day 12 of the infection the numbers of bacteria in the liver and the spleen were maximal. During the infection, activation of peritoneal macrophages could be demonstrated on the basis of three criteria, i.e., the ability to inhibit the proliferation of Toxoplasma gondii, an enhanced production of H2O2 and an increased expression of Ia Ag. The rate of in vitro intracellular killing of S. typhimurium by these activated macrophages was not increased compared to that for resident macrophages. To determine the growth of S. typhimurium in activated mice a nalidixic acid-resistant mutant strain, called S. typhimurium 510R, was used. The net growth rates of the mutant S. typhimurium 510R in the spleen of S. typhimurium 510-activated and normal mice were similar. However, in the liver of S. typhimurium 510-activated mice the number of S. typhimurium 510R did not change during 3 to 48 h after injection. The role of specific antibodies during the initial phase of the infection was negligible, because only low levels of antibodies were detected during the first 15 days of infection and the growth rates of S. typhimurium 510 in the spleen and liver of mice with high titers of antibodies were not significantly different from the rates in normal mice. The results of this study demonstrate that although macrophages become activated during an infection with S. typhimurium, these cells do not display an enhanced bactericidal activity in vitro and in vivo no significant effect on the growth rate of S. typhimurium in the spleen and a bacteriostatic effect in the liver is found. Hence macrophage activation is probably not very important in the host defense against S. typhimurium.
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Božić, Aleksandar, Robin C. Anderson, Tawni L. Crippen, Christina L. Swaggerty, Michael E. Hume, Ross C. Beier, Haiqi He, et al. "Inhibition of Salmonella Binding to Porcine Intestinal Cells by a Wood-Derived Prebiotic." Microorganisms 8, no. 7 (July 15, 2020): 1051. http://dx.doi.org/10.3390/microorganisms8071051.
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Numerous Salmonella enterica serovars can cause disease and contamination of animal-produced foods. Oligosaccharide-rich products capable of blocking pathogen adherence to intestinal mucosa are attractive alternatives to antibiotics as these have potential to prevent enteric infections. Presently, a wood-derived prebiotic composed mainly of glucose-galactose-mannose-xylose oligomers was found to inhibit mannose-sensitive binding of select Salmonella Typhimurium and Escherichia coli strains when reacted with Saccharomyces boulardii. Tests for the ability of the prebiotic to prevent binding of a green fluorescent protein (GFP)-labeled S. Typhimurium to intestinal porcine epithelial cells (IPEC-J2) cultured in vitro revealed that prebiotic-exposed GFP-labeled S. Typhimurium bound > 30% fewer individual IPEC-J2 cells than did GFP-labeled S. Typhimurium having no prebiotic exposure. Quantitatively, 90% fewer prebiotic-exposed GFP-labeled S. Typhimurium cells were bound per individual IPEC-J2 cell compared to non-prebiotic exposed GFP-labeled S. Typhimurium. Comparison of invasiveness of S. Typhimurium DT104 against IPEC-J2 cells revealed greater than a 90% decrease in intracellular recovery of prebiotic-exposed S. Typhimurium DT104 compared to non-exposed controls (averaging 4.4 ± 0.2 log10 CFU/well). These results suggest compounds within the wood-derived prebiotic bound to E. coli and S. Typhimurium-produced adhesions and in the case of S. Typhimurium, this adhesion-binding activity inhibited the binding and invasion of IPEC-J2 cells.
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PROMSOPONE, B., T. Y. MORISHITA, P. P. AYE, C. W. COBB, A. VELDKAMP, and J. R. CLIFFORD. "Evaluation of an Avian-Specific Probiotic and Salmonella typhimurium-Specific Antibodies on the Colonization of Salmonella typhimurium in Broilers." Journal of Food Protection 61, no. 2 (February 1, 1998): 176–80. http://dx.doi.org/10.4315/0362-028x-61.2.176.
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Salmonella typhimurium colonizes the intestinal tract of poultry and causes food-bome illness in humans. Reduction of S. typhimurium colonization in the intestinal tract of poultry reduces potential carcass contamination during slaughter. The purpose of this study was to determine the effect of an avian-specific probiotic and S. typhimurium-specific antibodies on the colonization of S. typhimurium in broilers and on body weights. Broiler chicks were spray-vaccinated at the hatchery with the commercial product, Avian Pac Plus, which contains Lactobacillus acidophilus, Streptococcus faecium, and S. typhimurium-specific antibodies. At placement, these chicks were administered Avian Pac Plus in the water. Six hours postplacement, chicks were orally challenged with 1.8 × 107 CFU of S. typhimurium. Chicks were administered Avian Pac Plus for two additional days postchallenge. Chicks were evaluated for S. typhimurium colonization and shedding every 3 to 4 days for the first 2 weeks and every 7 days for 6 weeks. The mean cecal and colonic concentration of S. typhimurium from the Avian Pac Plus-treated group was significantly lower at day 31 (P = 0.0001), day 38 (P = 0.0005), and day 43 (P = 0.0001) than the nontreated control group. These results indicated that a combination of Lactobacillus acidophilus, Streptococcus faecium, and S. typhimurium-specific antibodies have a beneficial effect in reducing the colonization of S. typhimurium in market-aged broilers.
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Kazlow, Philip G., Jeffrey Freed, Joel R. Rosh, Mark Reiner, Renata Dische, Keith Benkov, and Neal S. LeLeiko. "Salmonella typhimurium Appendicitis." Journal of Pediatric Gastroenterology and Nutrition 13, no. 1 (July 1991): 101–3. http://dx.doi.org/10.1097/00005176-199107000-00019.
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Totan, Mehmet. "NeonatalSalmonella typhimurium meningitis." Indian Journal of Pediatrics 68, no. 11 (November 2001): 1079–80. http://dx.doi.org/10.1007/bf02722362.
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Frayha, Rida A. "Salmonella typhimurium Bacteriuria." Archives of Internal Medicine 145, no. 4 (April 1, 1985): 645. http://dx.doi.org/10.1001/archinte.1985.00360040063014.
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PRICE-CARTER, M., P. ROY-CHOWDHURY, C. E. POPE, S. PAINE, G. W. DE LISLE, D. M. COLLINS, C. NICOL, and P. E. CARTER. "The evolution and distribution of phage ST160 within Salmonella enterica serotype Typhimurium." Epidemiology and Infection 139, no. 8 (October 18, 2010): 1262–71. http://dx.doi.org/10.1017/s0950268810002335.
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SUMMARYSalmonellosis is an internationally important disease of mammals and birds. Unique epidemics in New Zealand in the recent past include two Salmonella serovars: Salmonella enterica subsp. enterica serovar Typhimurium definitive type (DT) 160 (S. Typhimurium DT160) and S. Brandenburg. Although not a major threat internationally, in New Zealand S. Typhimurium DT160 has been the most common serovar isolated from humans, and continues to cause significant losses in wildlife. We have identified DNA differences between the first New Zealand isolate of S. Typhimurium DT160 and the genome-sequenced strain, S. Typhimurium LT2. All the differences could be accounted for in one cryptic phage ST64B, and one novel P22-like phage, ST160. The majority of the ST160 genome is almost identical to phage SE1 but has two regions not found in SE1 which are identical to the P22-like phage ST64T, suggesting that ST160 evolved from SE1 via two recombination events with ST64T. All of the New Zealand isolates of DT160 were identical indicating the clonal spread of this particular Salmonella. Some overseas isolates of S. Typhimurium DT160 differed from the New Zealand strain and contained SE1 phage rather than ST160. ST160 was also identified in New Zealand isolates of S. Typhimurium DT74 and S. Typhimurium RDNC-April06 and in S. Typhimurium DT160 isolates from the USA. The emergence of S. Typhimurium DT160 as a significant pathogen in New Zealand is postulated to have occurred due to the sensitivity of the Salmonella strains to the ST160 phage when S. Typhimurium DT160 first arrived.
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Xiao, Xingning, Biao Tang, Siyi Liu, Yujuan Suo, Hua Yang, and Wen Wang. "Evaluation of the Stress Tolerance of Salmonella with Different Antibiotic Resistance Profiles." BioMed Research International 2021 (September 14, 2021): 1–16. http://dx.doi.org/10.1155/2021/5604458.
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Disease caused by antibiotic-resistant Salmonella is a serious clinical problem that poses a great threat to public health. The present study is aimed at assessing differences in bacterial kinetics with different antibiotic resistance profiles under environmental stress and at developing microbial tolerance models in lettuce during storage from 4 to 36°C. The drug-resistance phenotypes of 10 Salmonella Typhimurium (S. Typhimurium) isolates were examined using the broth microdilution method. The results of 10 S. Typhimurium isolates in the suspensions showed that a slow trend towards reduction of drug-sensitive (DS) isolates in relation to the others though without statistical difference. Compared to DS S. Typhimurium SA62, greater bacterial reduction was observed in multidrug-resistant (MDR) S. Typhimurium HZC3 during lettuce storage at 4°C ( P < 0.05 ). It was likely that a cross-response between antibiotic resistance and food-associated stress tolerance. The greater growth in lettuce at 12°C was observed for DS S. Typhimurium SA62 compared to MDR S. Typhimurium HZC3 and was even statistically different ( P < 0.05 ), while no significant difference was observed for bacterial growth between MDR S. Typhimurium HZC3 and DS S. Typhimurium SA62 strains in lettuce storage from 16 to 36°C ( P > 0.05 ). The goodness-of-fit indices indicated the Log-linear primary model provided a satisfactory fit to describe the MDR S. Typhimurium HZC3 and DS S. Typhimurium SA62 survival at 4°C. A square root secondary model could be used to describe the effect of temperature (12, 16, 28, and 36°C) on the growth rates of S. Typhimurium HZC3 ( a d j − R 2 = 0.91 , RMSE = 0.06 ) and S. Typhimurium SA62 ( a d j − R 2 = 0.99 , RMSE = 0.01 ) derived from the Huang primary model. It was necessary to pay attention to the tolerance of antibiotic resistant bacteria under environmental stress, and the generated models could provide parts of the input data for microbial risk assessment of Salmonella with different antibiotic resistance profile in lettuce.
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Fu, Shiqian, Xinyan Yang, Lidong Pang, Shasha Cheng, Danliangmin Song, Xue Qin, Chaoxin Man, and Yujun Jiang. "A Novel Fluorescence Aptasensor Based on Magnetic Beads/Gold Nanoparticles/DNA-Stabilized Silver Nanoclusters for Detection of Salmonella Typhimurium." Foods 11, no. 4 (February 18, 2022): 595. http://dx.doi.org/10.3390/foods11040595.
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Salmonella Typhimurium (S. Typhimurium) is a globally distributed foodborne pathogen, which can lead to outbreaks of foodborne infectious diseases. It is essential to guarantee food safety by timely and correct detection of S. Typhimurium. In this investigation, an original fluorescence aptasensor was constructed to detect S. Typhimurium rapidly and sensitively. Through the coupling of magnetic beads, aptamer, and gold nanoparticles (AuNPs), a fluorescence quenching system with a “sandwich structure” was established. The aptamer acted as a link, and its specific binding to S. Typhimurium could release AuNPs from the system. Meanwhile, fluorescent DNA-stabilized silver nanoclusters (DNA-AgNCs) were synthesized. The fluorescence intensity changes caused by the fluorescence resonance energy transfer between DNA-AgNCs and AuNPs were utilized to detect S. Typhimurium. The purposed aptasensor exhibited high selectivity and sensitivity with a linear response to S. Typhimurium, ranging from 3.7 × 102 to 3.7 × 105 cfu/mL. The limit of detection (LOD) was estimated to be 98 cfu/mL within 2 h 10 min. In addition, this method showed excellent application for detection of S. Typhimurium in artificially contaminated milk, with LOD reaching 3.4 × 102 cfu/mL. Therefore, the developed fluorescence aptasensor has great potential to identify S. Typhimurium in foodstuffs.
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Fu, Songzhe, Sophie Octavia, Mark M. Tanaka, Vitali Sintchenko, and Ruiting Lan. "Defining the Core Genome of Salmonella enterica Serovar Typhimurium for Genomic Surveillance and Epidemiological Typing." Journal of Clinical Microbiology 53, no. 8 (May 27, 2015): 2530–38. http://dx.doi.org/10.1128/jcm.03407-14.
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Salmonella entericaserovar Typhimurium is the most commonSalmonellaserovar causing foodborne infections in Australia and many other countries. Twenty-oneS. Typhimurium strains fromSalmonellareference collection A (SARA) were analyzed using Illumina high-throughput genome sequencing. Single nucleotide polymorphisms (SNPs) in 21 SARA strains ranged from 46 to 11,916 SNPs, with an average of 1,577 SNPs per strain. Together with 47 strains selected from publicly availableS. Typhimurium genomes, theS. Typhimurium core genes (STCG) were determined. The STCG consist of 3,846 genes, a set that is much larger than that of the 2,882Salmonellacore genes (SCG) found previously. The STCG together with 1,576 core intergenic regions (IGRs) were defined as theS. Typhimurium core genome. Using 93S. Typhimurium genomes from 13 epidemiologically confirmed community outbreaks, we demonstrated that typing based on theS. Typhimurium core genome (STCG plus core IGRs) provides superior resolution and higher discriminatory power than that based on SCG for outbreak investigation and molecular epidemiology ofS. Typhimurium. STCG and STCG plus core IGR typing achieved 100% separation of all outbreaks compared to that of SCG typing, which failed to separate isolates from two outbreaks from background isolates. Defining theS. Typhimurium core genome allows standardization of genes/regions to be used for high-resolution epidemiological typing and genomic surveillance ofS.Typhimurium.
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Chen, Keyuan, Jiufeng Wang, Liang Guo, Jing Wang, Lan Yang, Ting Hu, Yiqing Zhao, Xue Wang, and Yaohong Zhu. "Lactobacillus johnsonii L531 Ameliorates Salmonella enterica Serovar Typhimurium Diarrhea by Modulating Iron Homeostasis and Oxidative Stress via the IRP2 Pathway." Nutrients 15, no. 5 (February 23, 2023): 1127. http://dx.doi.org/10.3390/nu15051127.
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Salmonella enterica serovar Typhimurium (S. Typhimurium) has evolved mechanisms to evade the host’s nutritional immunity and thus promote bacterial growth by using the iron in the host. However, the detailed mechanisms of S. Typhimurium induce dysregulation of iron homeostasis and whether Lactobacillus johnsonii L531 can alleviate the iron metabolism disorder caused by S. Typhimurium has not been fully elucidated. Here, we show that S. Typhimurium activated the expression of iron regulatory protein 2 (IRP2), transferrin receptor 1, and divalent metal transporter protein 1 and suppressed the expression of iron exporter ferroportin, which resulted in iron overload and oxidative stress, inhibiting the key antioxidant proteins NF-E2-related factor 2, Heme Oxygenase-1, and Superoxide Dismutase in vitro and in vivo. L. johnsonii L531 pretreatment effectively reversed these phenomena. IRP2 knockdown inhibited iron overload and oxidative damage induced by S. Typhimurium in IPEC-J2 cells, while IRP2 overexpression promoted iron overload and oxidative damage caused by S. Typhimurium. Interestingly, the protective effect of L. johnsonii L531 on iron homeostasis and antioxidant function was blocked following IRP2 overexpression in Hela cells, demonstrating that L. johnsonii L531 attenuates disruption of iron homeostasis and consequent oxidative damage caused by S. Typhimurium via the IRP2 pathway, which contributes to the prevention of S. Typhimurium diarrhea in mice.
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Murakami, Takashi, Yukihiko Hiroshima, Kentaro Miyake, Tasuku Kiyuna, Itaru Endo, Ming Zhao, and Robert M. Hoffman. "Efficacy of Tumor-Targeting Salmonella typhimurium A1-R against Malignancies in Patient-Derived Orthotopic Xenograft (PDOX) Murine Models." Cells 8, no. 6 (June 16, 2019): 599. http://dx.doi.org/10.3390/cells8060599.
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We developed tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R, a facultative anaerobe that is an auxotroph of leucine and arginine. The tumor-targeting efficacy of S. typhimurium A1-R was demonstrated in vivo and vitro using several malignant cell lines including melanoma, sarcoma, glioma, breast, pancreatic, colon, cervical, prostate, and ovarian cancers. Our laboratory also developed a patient-derived orthotopic xenograft (PDOX) model by implanting patient-derived malignant tumor fragments into orthotopic sites in mice. We reviewed studies of S. typhimurium A1-R against recalcitrant cancers. S. typhimurium A1-R was effective against all PDOX tumor models tested and showed stronger efficacies than chemotherapy or molecular-targeting therapy against some tumors. Furthermore, the synergistic efficacy of S. typhimurium A1-R when combined with chemotherapeutic agents, molecular-targeting agents, or recombinant methioninase was also demonstrated. We suggest potential clinical uses of this S. typhimurium A1-R treatment.
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Yang, Zhuokai, Xiaoyu Ma, Yan Li, Huidong Xu, Xinyi Han, Ruixia Wang, Pengyu Zhao, Ziyi Li, and Chao Shi. "Antimicrobial Activity and Antibiofilm Potential of Coenzyme Q0 against Salmonella Typhimurium." Foods 10, no. 6 (May 27, 2021): 1211. http://dx.doi.org/10.3390/foods10061211.
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Coenzyme Q0 (CoQ0) has anti-inflammatory and anti-tumor effects; however, the antimicrobial and antibiofilm activities of CoQ0 against Salmonella enterica serovar Typhimurium are unknown. Thus, we investigated the bacteriostatic and antibiofilm activities, along with the underlying mechanism, of CoQ0 against S. Typhimurium. The minimum inhibitory concentration (MIC) of CoQ0 against S. enterica serovars Typhimurium was 0.1–0.2 mg/mL (549–1098 µM), and CoQ0 at MIC and 2MIC decreased viable S. Typhimurium counts below detectable limits within 6 and 4 h, respectively. CoQ0 at 20MIC (4 mg/mL) reduced S. Typhimurium on raw chicken by 1.5 log CFU/cm3 within 6 h. CoQ0 effectively disrupted cell membrane integrity and induced morphological changes in the cell, resulting in hyperpolarization, decreased intracellular ATP concentrations, and cellular constituents leakage. Biofilm-associated S. Typhimurium cells were killed by CoQ0 treatment. These findings suggest that CoQ0 could be applied as a natural antibacterial substance for use against S. Typhimurium by the food industry.
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Hermans, Armand P. H. M., Tjakko Abee, Marcel H. Zwietering, and Henk J. M. Aarts. "Identification of Novel Salmonella enterica Serovar Typhimurium DT104-Specific Prophage and Nonprophage Chromosomal Sequences among Serovar Typhimurium Isolates by Genomic Subtractive Hybridization." Applied and Environmental Microbiology 71, no. 9 (September 2005): 4979–85. http://dx.doi.org/10.1128/aem.71.9.4979-4985.2005.
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ABSTRACT Genomic subtractive hybridization was performed between Salmonella enterica serovar Typhimurium LT2 and DT104 to search for novel Salmonella serovar Typhimurium DT104-specific sequences. The subtraction resulted mainly in the isolation of DNA fragments with sequence similarity to phages. Two fragments identified were associated with possible virulence factors. One fragment was identical to irsA of Salmonella serovar Typhimurium ATCC 14028, which is suggested to be involved in macrophage survival. The other fragment was homologous to HldD, an Escherichia coli O157:H7 lipopolysaccharide assembly-related protein. Five selected DNA fragments—irsA, the HldD homologue, and three fragments with sequence similarity to prophages—were tested for their presence in 17 Salmonella serovar Typhimurium DT104 isolates and 27 non-DT104 isolates by PCR. All five selected DNA fragments were Salmonella serovar Typhimurium DT104 specific among the serovar Typhimurium isolates tested. These DNA fragments can be useful for better detection and typing of Salmonella serovar Typhimurium DT104.
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RAJASHEKARA, G., E. HAVERLY, D. A. HALVORSON, K. E. FERRIS, D. C. LAUER, and K. V. NAGARAJA. "Multidrug-Resistant Salmonella Typhimurium DT104 in Poultry." Journal of Food Protection 63, no. 2 (February 1, 2000): 155–61. http://dx.doi.org/10.4315/0362-028x-63.2.155.
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Salmonella Typhimurium isolates from feed ingredients or poultry sources isolated during 1995 to 1997 from different geographical locations within Minnesota were examined for the presence of Salmonella Typhimurium definitive type 104 (DT104). Antibiotic susceptibility studies indicated that 15 of 50 isolates of Salmonella Typhimurium had an antibiotic resistance pattern (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) that is usually observed with multidrug-resistant Salmonella Typhimurium DT104. Of the 15 isolates showing the antibiotic resistance pattern, 8 isolates were phage type 104, 3 isolates were typed as phage type 104 complex, and the remaining 4 isolates belonged to phage types 193, 81, and 126. DT104 was recovered from both feed ingredients and poultry samples. Of the seven feed ingredient–associated Salmonella Typhimurium isolates, four were DT104, whereas only 7 of 43 poultry-associated Salmonella Typhimurium isolates were DT104. A repetitive sequence–based polymerase chain reaction (rep-PCR) of 50 isolates of Salmonella Typhimurium representing 13 phage types identified seven distinct fingerprint profiles. No correlation between phage type and rep-PCR type was noticed. Eleven Salmonella Typhimurium isolates belonging to DT104 and its complex were grouped into two closely related rep-PCR types.
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Skovierova, Henrieta, Gary Rowley, Bronislava Rezuchova, Dagmar Homerova, Claire Lewis, Mark Roberts, and Jan Kormanec. "Identification of the σ E regulon of Salmonella enterica serovar Typhimurium." Microbiology 152, no. 5 (May 1, 2006): 1347–59. http://dx.doi.org/10.1099/mic.0.28744-0.
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The extracytoplasmic function sigma factor, σ E, has been shown to play a critical role in virulence of Salmonella enterica serovar Typhimurium (S. Typhimurium). The previously optimized two-plasmid system has been used to identify S. Typhimurium promoters recognized by RNA polymerase containing σ E. This method allowed identification of 34 σ E-dependent promoters that direct expression of 62 genes in S. Typhimurium, 23 of which (including several specific for S. Typhimurium) have not been identified previously to be dependent upon σ E in Escherichia coli. The promoters were confirmed in S. Typhimurium and transcriptional start points of the promoters were determined by S1-nuclease mapping. All the promoters contained sequences highly similar to the consensus sequence of σ E-dependent promoters. The identified genes belonging to the S. Typhimurium σ E-regulon encode proteins involved in primary metabolism, DNA repair systems and outer-membrane biogenesis, and regulatory proteins, periplasmic proteases and folding factors, proposed lipoproteins, and inner- and outer-membrane proteins with unknown functions. Several of these σ E-dependent genes have been shown to play a role in virulence of S. Typhimurium.
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Li, Wanwu, Shuai Ma, Xiaolin Yan, Xinyue Wang, Huiying Li, and Lingyan Jiang. "The LysR-Type Transcription Regulator YhjC Promotes the Systemic Infection of Salmonella Typhimurium in Mice." International Journal of Molecular Sciences 24, no. 2 (January 9, 2023): 1302. http://dx.doi.org/10.3390/ijms24021302.
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Salmonella Typhimurium is a Gram-negative intestinal pathogen that can infect humans and a variety of animals, causing gastroenteritis or serious systemic infection. Replication within host macrophages is essential for S. Typhimurium to cause systemic infection. By analyzing transcriptome data, the expression of yhjC gene, which encodes a putative regulator in S. Typhimurium, was found to be significantly up-regulated after the internalization of Salmonella by macrophages. Whether yhjC gene is involved in S. Typhimurium systemic infection and the related mechanisms were investigated in this study. The deletion of yhjC reduced the replication ability of S. Typhimurium in macrophages and decreased the colonization of S. Typhimurium in mouse systemic organs (liver and spleen), while increasing the survival rate of the infected mice, suggesting that YhjC protein promotes systemic infection by S. Typhimurium. Furthermore, by using transcriptome sequencing and RT-qPCR assay, the transcription of several virulence genes, including spvD, iroCDE and zraP, was found to be down-regulated after the deletion of yhjC. Electrophoretic mobility shift assay showed that YhjC protein can directly bind to the promoter region of spvD and zraP to promote their transcription. These findings suggest that YhjC contributes to the systemic virulence of S. Typhimurium via the regulation of multiple virulence genes and YhjC could represent a promising target to control S. Typhimurium infection.
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Ling, Chong, Shujie Liang, Yan Li, Qingyun Cao, Hui Ye, Changming Zhang, Zemin Dong, Dingyuan Feng, Weiwei Wang, and Jianjun Zuo. "A Potential Adhesin/Invasin STM0306 Participates in Host Cell Inflammation Induced by Salmonella enterica Serovar Typhimurium." International Journal of Molecular Sciences 24, no. 9 (May 3, 2023): 8170. http://dx.doi.org/10.3390/ijms24098170.
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Salmonella enterica serovar typhimurium (S. Typhimurium) is a common Gram-negative foodborne pathogenic bacterium that causes gastrointestinal disease in humans and animals. It is well known that adhesins and invasins play crucial roles in the infection mechanism of S. Typhimurium. S. Typhimurium STM0306 has been denoted as a putative protein and its functions have rarely been reported. In this study, we constructed the STM0306 gene mutant strain of S. Typhimurium and purified the recombinant STM0306 from Escherichia coli. Deletion of the STM0306 gene resulted in reduced adhesion and invasion of S. Typhimurium to IPEC-J2, Caco-2, and RAW264.7 cells. In addition, STM0306 could bind to intestinal epithelial cells and induced F-actin modulation in IPEC-J2 cells. Furthermore, we found that STM0306 activated the nuclear factor kappa B (NF-κB) signaling pathway and increased the mRNA expression of pro-inflammatory cytokines such as IL-1β, TNF-α, as well as chemokine CXCL2, thus resulting in cellular inflammation in host cells. In vivo, the deletion of the STM0306 gene led to reduced pathogenicity of S. Typhimurium, as evidenced by lower fecal bacterial counts and reduced body weight loss in S. Typhimurium infected mice. In conclusion, the STM0306 of S. Typhimurium is an important adhesin/invasin involved in the pathogenic process and cellular inflammation of the host.
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Wongsen, Siwaporn, Duangporn Werawatganon, and Somying Tumwasorn. "Lactobacillus plantarum B7 attenuates Salmonella typhimurium infection in mice: preclinical study in vitro and in vivo." Asian Biomedicine 12, no. 5 (October 1, 2019): 211–18. http://dx.doi.org/10.1515/abm-2019-0022.
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Abstract Background Salmonella typhimurium is a cause of gastroenteritis including diarrhea. Lactobacillus plantarum is a probiotic widely used to prevent and treat diarrhea. Objectives To determine the protective effects of L. plantarum B7 on diarrhea in mice induced by S. typhimurium. Methods Inhibition of S. typhimurium growth by L. plantarum B7 was determined using an agar spot method. Mice were divided into 3 groups (n = 8 each): a control group, an S group administered 3 × 109 CFU/mL S. typhimurium, and an S + LP group administered 1 × 109 CFU/mL L. plantarum B7 and 3 × 109 CFU/mL S. typhimurium daily for 3 days. Counts of S. typhimurium and percentage of fecal moisture content (%FMC) were determined from stool samples. Serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and CXCL1 were determined. Results L. plantarum B7 produced a clear zone on S. typhimurium. There were significantly less S. typhimurium in the feces from mice in the S+LP group than in the S group. Serum levels of TNF-α, IL-6, and CXCL1 in mice from the S group were significantly higher than levels in the S+LP and control groups. Feces from mice in the S group were soft and loose, whereas in the S+LP group they were hard and rod shaped. The %FMC in the S+LP group was significantly less than in the S group. Conclusions L. plantarum B7 can inhibit growth of S. typhimurium, decrease levels of proinflammatory cytokines, and attenuate symptoms of diarrhea induced in mice by S. typhimurium.
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Allen, Chris A., Paula J. Fedorka-Cray, Andrés Vazquez-Torres, Mitsu Suyemoto, Craig Altier, L. Reeni Ryder, Ferric C. Fang, and Stephen J. Libby. "In Vitro and In Vivo Assessment of Salmonella enterica Serovar Typhimurium DT104 Virulence." Infection and Immunity 69, no. 7 (July 1, 2001): 4673–77. http://dx.doi.org/10.1128/iai.69.7.4673-4677.2001.
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ABSTRACT Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has become a widespread cause of human and other animal infection worldwide. The severity of clinical illness inS. enterica serovar Typhimurium DT104 outbreaks has led to the suggestion that this strain possesses enhanced virulence. In the present study, in vitro and in vivo virulence-associated phenotypes of several clinical isolates of S. enterica serovar Typhimurium DT104 were examined and compared to S. entericaserovar Typhimurium ATCC 14028s. The ability of these DT104 isolates to survive within murine peritoneal macrophages, invade cultured epithelial cells, resist antimicrobial actions of reactive oxygen and nitrogen compounds, and cause lethal infection in mice were assessed. Our results failed to demonstrate that S. enterica serovar Typhimurium DT104 isolates are more virulent than S. enterica serovar Typhimurium ATCC 14028s.
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Smith, Gerald R., Christine M. Roberts, and Dennis W. Schultz. "ACTIVITY OF CHI RECOMBINATIONAL HOTSPOTS IN SALMONELLA TYPHIMURIUM." Genetics 112, no. 3 (March 1, 1986): 429–39. http://dx.doi.org/10.1093/genetics/112.3.429.
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ABSTRACT Chi sites have previously been shown to stimulate homologous recombination by the Escherichia coli RecBC pathway. To test the activity of Chi in another organism, bacteriophage λ crosses were carried out in Salmonella typhimurium strains bearing the E. coli λ receptor protein. Chi is active in these crosses in S. typhimurium, but is less active than in the same crosses carried out in E. coli. The lower Chi activity in S. typhimurium appears to be intrinsic to the S. typhimurium RecBC enzyme, since the Chi activity in E. coli-S. typhimurium hybrids depends on the species of origin of their RecBC enzyme. For these studies we constructed an F' factor and a pBR322-derived plasmid carrying the thyA + recC + recB + argA + region of the S. typhimurium chromosome.
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Li, Pengcheng, Qinghua Yu, Xiaolan Ye, Zhisheng Wang, and Qian Yang. "Lactobacillus S-layer protein inhibition of Salmonella-induced reorganization of the cytoskeleton and activation of MAPK signalling pathways in Caco-2 cells." Microbiology 157, no. 9 (September 1, 2011): 2639–46. http://dx.doi.org/10.1099/mic.0.049148-0.
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Surface layer (S-layer) proteins are crystalline arrays of proteinaceous subunits that are present as the outermost component of the cell wall in several Lactobacillus species. The S-layer proteins have been shown to play a role in the antimicrobial activity of certain lactobacilli. However, it is not fully understood how the S-layer proteins exert this biological function. The aim of this study was to test the hypothesis that Lactobacillus acidophilus S-layer proteins antagonize Salmonella Typhimurium (S. Typhimurium) infection by protecting against F-actin cytoskeleton rearrangements and the activation of mitogen-activated protein kinase (MAPK) signalling pathways. Monolayer transepithelial electrical resistance (TER) was measured after S. Typhimurium infection in Caco-2 cultured human intestinal cells with L. acidophilus S-layer proteins. F-actin rearrangement and MAPK activation were also assessed by immunofluorescence staining or Western blotting. The results showed that when S. Typhimurium was co-incubated with S-layer proteins, the S. Typhimurium-induced Caco-2 cell F-actin rearrangement was reduced, and the S. Typhimurium-induced TER decrease and interleukin 8 (IL-8) secretion were attenuated. Additionally, L. acidophilus S-layer proteins could inhibit S. Typhimurium-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun amino-terminal kinase (JNK) and p38. This study indicates that L. acidophilus S-layer proteins are able to inhibit S. Typhimurium infection through blocking S. Typhimurium-induced F-actin rearrangements and S. Typhimurium-induced ERK1/2, JNK and p38 activation in Caco-2 cells. These data provide a rationale for the use of lactobacillus S-layer proteins as therapeutic and preventative agents, at least in infectious diarrhoea.
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Lee, Hyo-Ji, Sun-Hye Lee, Ji-Hui Jeon, Hyo-Jung Kim, Eui-Kwon Jeong, Min-Jeong Kim, Young Mee Jung, and Yu-Jin Jung. "Stimulation of Toll-Like Receptor 3 Diminishes Intracellular Growth of Salmonella Typhimurium by Enhancing Autophagy in Murine Macrophages." Metabolites 11, no. 9 (September 4, 2021): 602. http://dx.doi.org/10.3390/metabo11090602.
Full textAbstract:
The Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative Gram-negative bacterium that causes acute gastroenteritis and food poisoning. S. Typhimurium can survive within macrophages that are able to initiate the innate immune response after recognizing bacteria via various pattern-recognition receptors (PRRs), such as Toll-like receptors (TLRs). In this study, we investigated the effects and molecular mechanisms by which agonists of endosomal TLRs—especially TLR3—contribute to controlling S. Typhimurium infection in murine macrophages. Treatment with polyinosinic:polycytidylic acid (poly(I:C))—an agonist of TLR3—significantly suppressed intracellular bacterial growth by promoting intracellular ROS production in S. Typhimurium-infected cells. Pretreatment with diphenyleneiodonium (DPI)—an NADPH oxidase inhibitor—reduced phosphorylated MEK1/2 levels and restored intracellular bacterial growth in poly(I:C)-treated cells during S. Typhimurium infection. Nitric oxide (NO) production increased through the NF-κB-mediated signaling pathway in poly(I:C)-treated cells during S. Typhimurium infection. Intracellular microtubule-associated protein 1A/1B-light chain 3 (LC3) levels were increased in poly(I:C)-treated cells; however, they were decreased in cells pretreated with 3-methyladenine (3-MA)—a commonly used inhibitor of autophagy. These results suggest that poly(I:C) induces autophagy and enhances ROS production via MEK1/2-mediated signaling to suppress intracellular bacterial growth in S. Typhimurium-infected murine macrophages, and that a TLR3 agonist could be developed as an immune enhancer to protect against S. Typhimurium infection.
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THOUAND, G., P. VACHON, S. LIU, M. DAYRE, and M. W. GRIFFITHS. "Optimization and Validation of a Simple Method Using P22::luxAB Bacteriophage for Rapid Detection of Salmonella enterica Serotypes A, B, and D in Poultry Samples." Journal of Food Protection 71, no. 2 (February 1, 2008): 380–85. http://dx.doi.org/10.4315/0362-028x-71.2.380.
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A simple method was developed for the fast and inexpensive detection of Salmonella Typhimurium using a recombinant P22::luxAB phage. All the steps from phage production to detection were considered. A strain of Salmonella Typhimurium harboring the prophage P22::luxAB was grown in batch culture to produce spontaneously the recombinant bacteriophage. Batch production to stationary phase was better for propagation of the phage and led to a total population of 4.3 × 109 (±4.3 × 109) PFU/ml of P22, including only 1.4 × 106 (±1 × 106) PFU/ml harboring the luxAB genes. After preenrichment, a simple four-step bioassay was tested and optimized for several parameters. The detection limit of the luminometer was only 5 × 102 (±1.75 × 102) CFU Salmonella Typhimurium per ml, but increased to 1.5 × 104 (±1.17 × 104) CFU Salmonella Typhimurium per ml when the cells were in a complex matrix. The detection limit after the preenrichment was 6.5 × 103 (±1.5 × 103) CFU Salmonella Typhimurium per ml, but the detection limit after the preenrichment also increased markedly to 1.65 × 105 (±0.15 × 105) CFU Salmonella Typhimurium per ml when Salmonella Typhimurium was in a complex matrix. Finally, the bioassay was applied to the detection of Salmonella Typhimurium LT2 in 14 different feed and environmental samples (including duck feed, litters, and feces) spiked either before or after the preenrichment process. It was possible to detect Salmonella Typhimurium LT2 in all samples within 16 h.
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Lv, Xiaoye, and Jun-Hu Cheng. "Evaluation of the Effects of Cold Plasma on Cell Membrane Lipids and Oxidative Injury of Salmonella typhimurium." Molecules 27, no. 3 (January 19, 2022): 640. http://dx.doi.org/10.3390/molecules27030640.
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Salmonella typhimurium (S. typhimurium) is a major causative agent of foodborne illness worldwide. Cold plasma (CP) was used to inactivate S. typhimurium and to investigate the effect of CP on cell membrane lipids and oxidative injury of cells. Results indicated that the inactivation effect of CP on S. typhimurium was positively correlated with the treatment time and voltage. S. typhimurium was undetectable (total number of surviving colonies <2 log CFU/mL) after 5 min treatment with the voltage of 50 V. CP treatment caused damage to the cell membrane of S. typhimurium and the leakage of cell contents, and the relative content of unsaturated fatty acids in cell membrane decreased. Cell membrane lipids were oxidized; the malondialdehyde content increased from 0.219 nmol/mL to 0.658 nmol/mL; the catalase activity of S. typhimurium solution increased from 751 U/mL to 2542 U/mL; and the total superoxide dismutase activity increased from 3.076 U/mL to 4.54 U/mL, which confirmed the oxidative damage in S. typhimurium cell membrane caused by CP treatment. It was demonstrated that the potential application of plasma-mediated reactive oxygen species is suitable for destroying the structures of the cell membrane and ensuring the microbial safety of fresh food samples.
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KIM, H. J., S. H. PARK, T. H. LEE, B. H. NAHM, Y. H. CHUNG, K. H. SEO, and H. Y. KIM. "Identification of Salmonella enterica Serovar Typhimurium Using Specific PCR Primers Obtained by Comparative Genomics in Salmonella Serovars." Journal of Food Protection 69, no. 7 (July 1, 2006): 1653–61. http://dx.doi.org/10.4315/0362-028x-69.7.1653.
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Salmonella enterica serovar Typhimurium is a major foodborne pathogen throughout the world. Until now, the specific target genes for the detection and identification of serovar Typhimurium have not been developed. To determine the specific probes for serovar Typhimurium, the genes of serovar Typhimurium LT2 that were expected to be unique were selected with the BLAST (Basic Local Alignment Search Tool) program within GenBank. The selected genes were compared with 11 genomic sequences of various Salmonella serovars by BLAST. Of these selected genes, 10 were expected to be specific to serovar Typhimurium and were not related to virulence factor genes of Salmonella pathogenicity island or to genes of the O and H antigens of Salmonella. Primers for the 10 selected genes were constructed, and PCRs were evaluated with various genomic DNAs of Salmonella and non-Salmonella strains for the specific identification of Salmonella serovar Typhimurium. Among all the primer sets for the 10 genes, STM4497 showed the highest degree of specificity to serovar Typhimurium. In this study, a specific primer set for Salmonella serovar Typhimurium was developed on the basis of the comparison of genomic sequences between Salmonella serovars and was validated with PCR. This method of comparative genomics to select target genes or sequences can be applied to the specific detection of microorganisms.
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Miyake, Kentaro, Tasuku Kiyuna, Shukuan Li, Qinghong Han, Yuying Tan, Ming Zhao, Hiromichi Oshiro, et al. "Combining Tumor-Selective Bacterial Therapy with Salmonella typhimurium A1-R and Cancer Metabolism Targeting with Oral Recombinant Methioninase Regressed an Ewing’s Sarcoma in a Patient-Derived Orthotopic Xenograft Model." Chemotherapy 63, no. 5 (2018): 278–83. http://dx.doi.org/10.1159/000495574.
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Background: Ewing’s sarcoma (ES) is a recalcitrant disease in need of transformative therapeutics. Objectives: The aim of this study was to investigate the efficacy of tumor-selective Salmonella typhimurium A1-R combined with tumor metabolism targeting with oral administration of recombinant methioninase (o-rMETase), on an ES patient-derived orthotopic xenograft (PDOX) model. Methods: The ES PDOX models were previously established in the right chest wall. The ES PDOX models were randomized into 5 groups when the tumor volume reached 80 mm3: G1: untreated control; G2: doxorubicin; G3: S. typhimurium A1-R; G4: o-rMETase; G5: S. typhimurium A1-R combined with o-rMETase. All mice were sacrificed on day 15. Body weight and tumor volume were assessed twice a week. Results: S. typhimurium A1-R and o-rMETase respectively suppressed tumor growth as monotherapies (p = 0.050 and p = 0.032). S. typhimurium A1-R combined with o-rMETase regressed tumor growth significantly compared to untreated group on day 15 (p < 0.032). S. typhimurium A1-R combined with o-rMETase group was significantly more effective than S. typhimurium A1-R or o-rMETase monotherapy (p = 0.032, p = 0.032). Conclusions: The present results suggest that the combination of S. typhimurium A1-R and o-rMETase has promise to be a transformative therapy for ES.
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Habyarimana, Fabien, Matthew C. Swearingen, Glenn M. Young, Stephanie Seveau, and Brian M. M. Ahmer. "Yersinia enterocolitica Inhibits Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Cellular Uptake." Infection and Immunity 82, no. 1 (October 14, 2013): 174–83. http://dx.doi.org/10.1128/iai.00984-13.
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ABSTRACTYersinia enterocoliticabiovar 1B employs two type three secretion systems (T3SS), Ysa and Ysc, which inject effector proteins into macrophages to prevent phagocytosis. Conversely,Salmonella entericaserovar Typhimurium uses a T3SS encoded bySalmonellapathogenicity island 1 (SPI1) to actively invade cells that are normally nonphagocytic and a second T3SS encoded by SPI2 to survive within macrophages. Given the distinctly different outcomes that occur with regard to host cell uptake ofS. Typhimurium andY. enterocolitica, we investigated how each pathogen influences the internalization outcome of the other.Y. enterocoliticareducesS. Typhimurium invasion of HeLa and Caco-2 cells to a level similar to that observed using anS. Typhimurium SPI1 mutant alone. However,Y. enterocoliticahad no effect onS. Typhimurium uptake by J774.1 or RAW264.7 macrophage-like cells.Y. enterocoliticawas also able to inhibit the invasion of epithelial and macrophage-like cells byListeria monocytogenes.Y. enterocoliticamutants lacking either the Ysa or Ysc T3SS were partially defective, while double mutants were completely defective, in blockingS. Typhimurium uptake by epithelial cells.S. Typhimurium encodes a LuxR homolog, SdiA, which detectsN-acylhomoserine lactones (AHLs) produced byY. enterocoliticaand upregulates the expression of an invasin (Rck) and a putative T3SS effector (SrgE). Two different methods of constitutively activating theS. Typhimurium SdiA regulon failed to reverse the uptake blockade imposed byY. enterocolitica.
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Sydenham, Mark, Gillian Douce, Frances Bowe, Saddif Ahmed, Steve Chatfield, and Gordon Dougan. "Salmonella enterica Serovar TyphimuriumsurA Mutants Are Attenuated and Effective Live Oral Vaccines." Infection and Immunity 68, no. 3 (March 1, 2000): 1109–15. http://dx.doi.org/10.1128/iai.68.3.1109-1115.2000.
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ABSTRACT A previously described attenuated TnphoA mutant (BRD441) of Salmonella enterica serovar Typhimurium C5 (I. Miller, D. Maskell, C. Hormaeche, K. Johnson, D. Pickard, and G. Dougan, Infect. Immun. 57:2758–2763, 1989) was characterized, and the transposon was shown to be inserted in surA, a gene which encodes a peptidylprolyl-cis,trans-isomerase. A defined surA deletion mutation was introduced into S. enterica serovar Typhimurium C5 and the mutant strain, namedS. enterica serovar Typhimurium BRD1115, was extensively characterized both in vitro and in vivo. S. entericaserovar Typhimurium BRD1115 was found to be defective in the ability to adhere to and invade eukaryotic cells. Furthermore, S. enterica serovar Typhimurium BRD1115 was attenuated by at least 3 log units when administered orally or intravenously to BALB/c mice. Complementation of the mutation with a plasmid carrying the intactsurA gene almost completely restored the virulence of BRD1115. In addition, S. enterica serovar Typhimurium BRD1115 demonstrated potential as a vaccine candidate, since mice immunized with BRD1115 were protected against subsequent challenge withS. enterica serovar Typhimurium C5. S. entericaserovar Typhimurium BRD1115 also showed potential as a vehicle for the effective delivery of heterologous antigens, such as the nontoxic, protective fragment C domain of tetanus toxin, to the murine immune system.
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Tanaka, Y., N. Shimizu, H. Tsukatani, N. Sera, and S. Kitamori. "The mutagenicity of amino-derivatives of diphenyl ether herbicides in new Salmonella typhimurium YG tester strains." Water Science and Technology 46, no. 11-12 (December 1, 2002): 395–400. http://dx.doi.org/10.2166/wst.2002.0768.
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In this study, we examined the mutagenicity of four diphenyl ether herbicides and their amino derivatives in Salmonella typhimurium TA tester strains and YG tester strains. YG tester strains have been newly developed for sensitive detection of specific chemicals. S. typhimurium YG 1021, YG 1024, YG 1026 and YG 1029 strains are sensitive to mutagenic nitoroarenes and hydroxyamines. S. typhimurium YG 3003 is a strain that is sensitive to some oxidative mutagens. And S. typhimurium YG 7108 is useful for detection of mutagenic alkylating agents. As a result, each amino derivative of diphenyl ether herbicides is more mutagenic than its parent herbicide in S. typhimurium TA and YG tester strains with metabolic activation by S9 mixture. Moreover, S. typhimurium YG tester strains are more useful for highly sensitive detection of mutagens than S. typhimurium TA tester strains. WE also examined the production of amino derivatives in a water environment from parent herbicides. It was clear that diphenyl ether herbicides rapidly transform to amino derivatives in a water environment.
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ZHAO, TONG, MICHAEL P. DOYLE, PAULA J. FEDORKA-CRAY, PING ZHAO, and SCOTT LADELY. "Occurrence of Salmonella enterica Serotype Typhimurium DT104A in Retail Ground Beef." Journal of Food Protection 65, no. 2 (February 1, 2002): 403–7. http://dx.doi.org/10.4315/0362-028x-65.2.403.
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Surveillance data of cattle and human isolates of Salmonella enterica serovar Typhimurium DT104 indicate that this pathogen emerged worldwide in the 1980s, particularly in cattle. Studies were conducted to determine the prevalence of Salmonella Typhimurium DT104 in ground beef. Samples were also tested for the presence of generic Escherichia coli. A total of 404 fresh ground beef samples obtained at retail stores from New York, San Francisco, Philadelphia, Denver, Atlanta, Houston, and Chicago were shipped overnight to Georgia for processing. Salmonella spp. were isolated from 14 (3.5%) samples. Eight different serotypes were identified among the isolates, including Salmonella Typhimurium (5), Salmonella Lille (3), Salmonella Montevideo (1), Salmonella Hadar (1), Salmonella Meleagridis (1), Salmonella Cerro (1), Salmonella Kentucky (1), and Salmonella Muenster (1). Antibiotic resistance profiles indicated that all five Salmonella Typhimurium isolates were resistant to ampicillin, streptomycin, sulfamethoxazole, ticarcillin, and tetracycline but that they were sensitive to chloramphenicol. Phage typing revealed that all five Salmonella Typhimurium isolates were DT104A, a subtype of DT104. All five Salmonella Typhimurium DT104A isolates were obtained from ground beef sampled from retail outlets in San Francisco. Pulsed-field gel electrophoresis (PFGE) genomic DNA profiles of the five Salmonella Typhimurium DT104A isolates from ground beef were indistinguishable from those of four control Salmonella Typhimurium DT104 penta-resistant isolates from cattle that were used for comparison. A total of 102 generic E. coli isolates were obtained, only three of which were multi-resistant to antibiotics. In addition, three E. coli isolates were recovered from samples that were positive for Salmonella Typhimurium DT104A. No correlation of antibiotic resistance profiles was observed between Salmonella Typhimurium DT104A and generic E. coli, as two of the three E. coli isolates were susceptible to all of the antibiotics tested, and the third isolate was resistant only to cephalothin. These data indicate that Salmonella Typhimurium DT104A can be isolated from retail ground beef, and because there was little overlap in antibiotic resistance patterns between Salmonella Typhimurium DT104A and E. coli isolates from the same ground beef samples, these limited data suggest that the transfer of antibiotic resistance genes among enteric bacteria in ground beef may not be common. This latter observation is further supported by the limited isolation of multiantibiotic-resistant E. coli from retail ground beef.
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Mynott, Tracey L., Ben Crossett, and S. Radhika Prathalingam. "Proteolytic Inhibition of Salmonella enterica Serovar Typhimurium-Induced Activation of the Mitogen-Activated Protein Kinases ERK and JNK in Cultured Human Intestinal Cells." Infection and Immunity 70, no. 1 (January 2002): 86–95. http://dx.doi.org/10.1128/iai.70.1.86-95.2002.
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ABSTRACT Bromelain, a mixture of cysteine proteases from pineapple stems, blocks signaling by the mitogen-activated protein (MAP) kinases extracellular regulated kinase 1 (ERK-1) and ERK-2, inhibits inflammation, and protects against enterotoxigenic Escherichia coli infection. In this study, we examined the effect of bromelain on Salmonella enterica serovar Typhimurium infection, since an important feature of its pathogenesis is its ability to induce activation of ERK-1 and ERK-2, which leads to internalization of bacteria and induction of inflammatory responses. Our results show that bromelain dose dependently blocks serovar Typhimurium-induced ERK-1, ERK-2, and c-Jun NH2-terminal kinase (JNK) activation in Caco-2 cells. Bromelain also blocked signaling induced by carbachol and anisomycin, pharmacological MAP kinase agonists. Despite bromelain inhibition of serovar Typhimurium-induced MAP kinase signaling, it did not prevent subsequent invasion of the Caco-2 cells by serovar Typhimurium or alter serovar Typhimurium -induced decreases in resistance across Caco-2 monolayers. Surprisingly, bromelain also did not block serovar Typhimurium-induced interleukin-8 (IL-8) secretion but synergized with serovar Typhimurium to enhance IL-8 production. We also found that serovar Typhimurium does not induce ERK phosphorylation in Caco-2 cells in the absence of serum but that serovar Typhimurium-induced invasion and decreases in monolayer resistance are unaffected. Collectively, these data indicate that serovar Typhimurium-induced invasion of Caco-2 cells, changes in the resistance of epithelial cell monolayers, and IL-8 production can occur independently of the ERK and JNK signaling pathways. Data also confirm that bromelain is a novel inhibitor of MAP kinase signaling pathways and suggest a novel role for proteases as inhibitors of signal transduction pathways in intestinal epithelial cells.
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LERICHE, VALÉRIE, and BRIGITTE CARPENTIER. "Viable but Nonculturable Salmonella typhimurium in Single- and Binary-Species Biofilms in Response to Chlorine Treatment." Journal of Food Protection 58, no. 11 (November 1, 1995): 1186–91. http://dx.doi.org/10.4315/0362-028x-58.11.1186.
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The survival after chlorine stress of the biofilm form of Salmonella typhimurium both alone and in association with the biofilm form of Pseudomo fluorescens was investigated. P. fluorescens showed the best adhesion and more extended growth than S. typhimurium when the two strains were cocultured. The presence of P. fluorescens resulted in an increased resistance of S. typhimurium to chlorine. This phenomenon, which was already seen in 1-day biofilms, increased in 4-day biofilms. Viable but nonculturable cells were observed only in 4-day single-species S. typhimurium biofilms subjected to chlorine stress; only 50% of substrate-responsive bacteria (SRB) were culturable. When daily cycles of disinfection, neutralization, and culture medium supply were performed with S. typhimurium biofilms for 4 days, only 20% of the SRB remained culturable. The chlorine consumption of such biofilms was more than twice that of 4-day single-species S. typhimurium biofilms.
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AHN, JUHEE, SONGRAE KIM, LAE-SEUNG JUNG, and DEBABRATA BISWAS. "In Vitro Assessment of the Susceptibility of Planktonic and Attached Cells of Foodborne Pathogens to Bacteriophage P22-Mediated Salmonella Lysates." Journal of Food Protection 76, no. 12 (December 1, 2013): 2057–62. http://dx.doi.org/10.4315/0362-028x.jfp-13-183.
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This study was designed to evaluate the lytic activity of bacteriophage P22 against Salmonella Typhimurium ATCC 19585 (Salmonella Typhimurium P22−) at various multiplicities of infections (MOIs), the susceptibility of preattached Salmonella cells against bacteriophage P22, and the effect of P22-mediated bacterial lysates (extracellular DNA) on the attachment ability of Listeria monocytogenes ATCC 7644 and enterohemorrhagic Escherichia coli ATCC 700927 to surfaces. The numbers of attached Salmonella Typhimurium P22− cells were effectively reduced to below the detection limit (1 log CFU/ml) at the fixed inoculum levels of 3 × 102 CFU/ml (MOI = 3.12) and 3 × 103 CFU/ml (MOI = 4.12) by bacteriophage P22. The attached Salmonella Typhimurium P22− cells remained more than 2 log CFU/ml, with increasing inoculum levels from 3 × 104 to 3 × 107 CFU/ml infected with 4 × 108 PFU/ml of P22. The number of preattached Salmonella Typhimurium P22− cells was noticeably reduced by 2.72 log in the presence of P22. The highest specific attachment ability values for Salmonella Typhimurium P22−, Salmonella Typhimurium ATCC 23555 carrying P22 prophage (Salmonella Typhimurium P22+), L. monocytogenes, and enterohemorrhagic E. coli were 2.09, 1.06, 1.86, and 1.08, respectively, in the bacteriophage-mediated cell-free supernatants (CFS) containing high amounts of extracellular DNA. These results suggest that bacteriophages could potentially be used to effectively eliminate planktonic and preattached Salmonella Typhimurium P22− cells with increasing MOI. However, further research is needed to understand the role of bacteriophage-induced lysates in bacterial attachment, which can provide useful information for the therapeutic use of bacteriophage in the food system.
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Chattopadhyay, Anindita, Nirmal Robinson, Jagdeep K. Sandhu, B. Brett Finlay, Subash Sad, and Lakshmi Krishnan. "Salmonella enterica Serovar Typhimurium-Induced Placental Inflammation and Not Bacterial Burden Correlates with Pathology and Fatal Maternal Disease." Infection and Immunity 78, no. 5 (March 1, 2010): 2292–301. http://dx.doi.org/10.1128/iai.01186-09.
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ABSTRACT Food-borne infections caused by Salmonella enterica species are increasing globally, and pregnancy poses a high risk. Pregnant mice rapidly succumb to S. enterica serovar Typhimurium infection. To determine the mechanisms involved, we addressed the role of inflammation and bacterial burden in causing placental and systemic disease. In vitro, choriocarcinoma cells were a highly conducive niche for intracellular S. Typhimurium proliferation. While infection of mice with S. Typhimurium wild-type (WT) and mutant (ΔaroA and ΔinvA) strains led to profound pathogen proliferation and massive burden within placental cells, only the virulent WT S. Typhimurium infection evoked total fetal loss and adverse host outcome. This correlated with substantial placental expression of granulocyte colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) and increased serum inflammatory cytokines/chemokines, such as G-CSF, IL-6, CCL1, and KC, evoked by WT S. Typhimurium infection. In contrast, infection with high doses of S. Typhimurium ΔaroA, despite causing massive placental infection, resulted in reduced inflammatory cellular and cytokine response. While S. Typhimurium WT bacteria were dispersed in large numbers across all regions of the placenta, including the deeper labyrinth trophoblast, S. Typhimurium ΔaroA bacteria localized primarily to the decidua. This correlated with the widespread placental necrosis accompanied by neutrophil infiltration evoked by the S. Typhimurium WT bacteria. Thus, the ability of Salmonella to localize to deeper layers of the placenta and the nature of inflammation triggered by the pathogen, rather than bacterial burden, profoundly influenced placental integrity and host survival.
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Ryan, Daniel, Niladri Bhusan Pati, Urmesh K. Ojha, Chandrashekhar Padhi, Shilpa Ray, Sangeeta Jaiswal, Gajinder P. Singh, et al. "Global Transcriptome and Mutagenic Analyses of the Acid Tolerance Response of Salmonella enterica Serovar Typhimurium." Applied and Environmental Microbiology 81, no. 23 (September 18, 2015): 8054–65. http://dx.doi.org/10.1128/aem.02172-15.
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ABSTRACTSalmonella entericaserovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability ofS. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, whichS. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability ofS. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis ofS. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than −1.5-fold;P< 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute toS. Typhimurium ATR and virulence. Mutants lacking genes encoding the K+binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed variedin vitrovirulence characteristics. This study offers greater insight into the transcriptome changes ofS. Typhimurium under the ATR and provides a framework for further research on the subject.
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Li, Qingjie, Lianping Wang, Jingwen Xu, Shuang Liu, Zeyu Song, Tingting Chen, Xuming Deng, Jianfeng Wang, and Qianghua Lv. "Quercitrin Is a Novel Inhibitor of Salmonella enterica Serovar Typhimurium Type III Secretion System." Molecules 28, no. 14 (July 17, 2023): 5455. http://dx.doi.org/10.3390/molecules28145455.
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The purpose was to screen type III secretory system (T3SS) inhibitors of Salmonella enterica serovar Typhimurium (S. Typhimurium) from natural compounds. The pharmacological activities and action mechanisms of candidate compounds in vivo and in vitro were systematically studied and analyzed. Using a SipA-β-lactamase fusion reporting system, we found that quercitrin significantly blocked the translocation of SipA into eukaryotic host cells without affecting the growth of bacteria. Adhesion and invasion assay showed that quercitrin inhibited S. Typhimurium invasion into host cells and reduced S. Typhimurium mediated host cell damage. β-galactosidase activity detection and Western blot analysis showed that quercitrin significantly inhibited the expression of SPI-1 genes (hilA and sopA) and effectors (SipA and SipC). The results of animal experiments showed that quercitrin significantly reduced colony colonization and alleviated the cecum pathological injury of the infected mice. Small molecule inhibitor quercitrin directly inhibited the function of T3SS and provided a potential antibiotic alternative against S. Typhimurium infection. Importance: T3SS plays a crucial role in the bacterial invasion and pathogenesis of S. Typhimurium. Compared with conventional antibiotics, small molecules could inhibit the virulence factors represented by S. Typhimurium T3SS. They have less pressure on bacterial vitality and a lower probability of producing drug resistance. Our results provide strong evidence for the development of novel inhibitors against S. Typhimurium infection.
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SUMNER, SUSAN S., EVA A. WALLNER-PENDLETON, GLENN W. FRONING, and LA VERNE E. STETSON. "Inhibition of Salmonella typhimurium on Agar Medium and Poultry Skin by Ultraviolet Energy." Journal of Food Protection 59, no. 3 (March 1, 1996): 319–21. http://dx.doi.org/10.4315/0362-028x-59.3.319.
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Ultraviolet radiation (UV) was effective in destroying Salmonella typhimurium on agar plates and poultry skin. Agar plates inoculated with varying numbers of colony-forming units (CFU) of S. typhimurium (1.2 × 102 to 1.7 × 109) were subjected to different doses of UV light to determine optimal killing. Poultry skin was also inoculated with varying CFU of S. typhimurium per 2 cm2 of skin and subjected to UV light. UV light treatment of inoculated agar plates revealed almost complete elimination (99.9%) of S. typhimurium at 2,000 μW · s · cm−2. Bacterial reduction was less effective on the surface of poultry skin when a 80.5% reduction in S. typhimurium was obtained at 2,000 μW · s · cm−2.
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Ren, Zhongyue, Lingling Peng, Shufang Chen, Yi Pu, Huihui Lv, Hua Wei, and Cuixiang Wan. "Lactiplantibacillus plantarum 1201 Inhibits Intestinal Infection of Salmonella enterica subsp. enterica Serovar Typhimurium Strain ATCC 13311 in Mice with High-Fat Diet." Foods 11, no. 1 (December 29, 2021): 85. http://dx.doi.org/10.3390/foods11010085.
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Salmonella Typhimurium is widely distributed in food. It can colonise the gastrointestinal tract after ingestion, causing lamina propria edema, inflammatory cell infiltration, and mucosal epithelial decomposition. A high-fat diet (HFD) can induce an inflammatory response, but whether HFD can increase the infection level of S. Typhimurium is unknown. We established a model of Salmonella enterica subsp. enterica serovar Typhimurium strain ATCC 13311 ATCC 13311 infection in healthy adult mice with a maintenance diet (MD) or HFD to explore the effect of Lactiplantibacillus plantarum 1201 intervention on S. Typhimurium ATCC 13311 colonization and its protective effects on mice. HFD exacerbated the infection of S. Typhimurium ATCC 13311, while the intervention of L. plantarum 1201 effectively mitigated this process. L. plantarum 1201 can reduce the colonies of S. ATCC 13311 in the intestines and tissues; and reduce intestinal inflammation by down-regulating the level of TLR4/NF-κB pathway related proteins in serum and the expression of related inflammatory factors in the colon and jejunum. Since L. plantarum 1201 can inhibit the colonization of S. Typhimurium ATCC 13311 and relieve inflammation in HFD, current research may support the use of L. plantarum 1201 to prevent S. Typhimurium infection.