Salmonella evades host innate immunity via AvrA mediated inhibition of cytokine production and pro‐apoptotic pathways
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The enteric pathogen Salmonella typhimurium suppresses host innate immune responses via secretion of preformed effector proteins into host cells during invasion. One of these proteins, AvrA, has potent immunosuppressive and anti‐apoptotic effects in mammalian cultured cells and in a Drosophila animal model via inhibition of the JNK pathway. To study the role of AvrA in a murine model of natural infection, wild type Salmonella harboring AvrA or an isogenic AvrA null mutant Salmonella were orally administered to mice pretreated with streptomycin and infectious phenotypes compared. Infection with the AvrA null Salmonella caused increased levels of apoptosis in the cecal epithelium and in lymphoid resident monocytic cells at 6h post infection. Additionally, the AvrA null Salmonella induced increased serum cytokine levels, including KC, IL‐1beta and TNFalpha. Furthermore, AvrA null Salmonella caused increased hepatosplenomegaly by 7 days post infection. This coincided with increased bacterial load in the liver, spleen and mesenteric lymph node, and more severe weight loss. We conclude that Salmonella evades host innate immunity and gains systemic access/dissemination via AvrA mediated inhibition of cytokine production and apoptosis. Research funding provided by NIH AI 64462.Salmonella enteritidis
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Summary We studied serovars of Salmonella strains isolated from chicken and humans in Lithuania over the period from 2000 to 2004. Salmonella strains were isolated and identified according to the techniques recommended by International Organisation for Standardization (Microbiology of Food and Animal Feeding Stuff – Horizontal Method for the Detection of Salmonella , 1998, ISO, Geneva). The per cent of infected flocks with Salmonella in separate years was between 1.01% and 3.2% during the period of investigation. The contamination rate of broiler legs and breasts was higher (2.36% and 4.25%) than that of wings (0.82%). Eighteen serovars of Salmonella were identified from the total 300 isolated samples. The most prevalent serovars in chicken were Salmonella Enteritidis, Salmonella Infantis and Salmonella Typhimurium. Other serovars such as Salmonella Montevideo, Salmonella Djugu, Salmonella Isangi, Salmonella Bovismorbificans, Salmonella Mbankada, Salmonella Hadar were detected only in one to two samples. In general, similar serovars of Salmonella were found in humans and chicken ( S. Enteritidis and S. Typhimurium), although distinct serovars were found only in humans or only in chicken. Analysis of the distribution of Salmonella serovars in humans during the seasons of the year indicated that the highest incidence of Salmonella was in Summer and in the beginning of Autumn. Analysis of the distribution of serovars during the study period indicated that there is a shift over time in both humans and chicken.
Flock
Salmonella enteritidis
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Strain (injury)
Salmonella enterica
Salmonella enteritidis
Competitive exclusion
Salmonella infection
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Objective:The spleen-deficiency-suffering mice models are observed dynamically on the perspective of pharmacokinetics and by radioactive tracer method,and the effect of spleen-reinforcing therapy on the mice's obsorption of Fe and the process of transporting and distribution is observed as well,so that the relationship between the spleen's function of dominating transporting/ dysfunction of the spleen in transporting and Fe metabolim is researched; The biological meaning of spleen's function of dominating transporting is discussed;The scientific content of the important TCM theories of spleen's dominating the transporting and spleen's determining the condition of the acquired construction is revealed;the experimental basis is provided for the research on spleen's functions and /or the essence of spleen-deficiency syndrome.Method: 80 Male SD mice are divided by random into normal group,normal reinforcing-spleen group,spleen-deficiency group,reinforcing-spleen-deficiency group.The mice model are fed 59 Fe Cl3 and 0.2 ml water-floating fluid at one time;the mice of the groups of normal reinforcing-spleen and reinforcing-spleen-deficiency are fed 1.5ml 1:1 Si Jun Zi Tang;the groups of normal and spleen-deficiency are fed 1.5 ml normal sanile once a day.3 rats of each group will be selected by random at 0.5,1,2,4,8 and 14 phase and are made dead by eyeball blood letting method,and then radio 59 Fe level is measured by Y radio-immunity counter after the organs and tissues of spleen,liver,small intestine,stomach and kidney are extracted,and the pharmacokinetics change of radio Fe's transporting and distribution from the whole body's circulatory system to the rats's tissues and organs.Results: 59 Fe transporting exists significant difference in the condition of spleen-deficiency and reinforcing-spleen,the therapy of reinforcing-spleen improve the transporting and distribution of 59 Fe of the mice.Conclusions: 59 Fe's transporting process from blood circulatory system to the organs and tissues decreased in the condition of spleen-deficiency,the therapy of reinforcing-spleen can promote the transporting of 59 Fe in the tissues and organs of the mice,especially concentrating on the spleen,which shows that Si Jun Zi Tang has the function of regulating the spleen-deficiency by reinforcing the spleen so that the substance transporting system of the organism is regulated.
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Salmonella is a pathogenic Gram-negative bacterium and important zoonotic pathogen survive in host cell, which is well known to cause gastrointestinal infections and even death in human through food contamination. Salmonella survives and reproduces within cells in two forms of cytosolic Salmonella and vacuolar Salmonella . However, the current researches on the mechanism of Salmonella infection was mostly based on the total numbers, and there is no clear distinction between cytosolic Salmonella and vacuolar Salmonella . This article combined biotin-streptavidin-amplified enzyme-linked immunosorbent assay(BA-ELISA) and Flat colony counting method to separate and quantify cytosolic Salmonella and vacuolar Salmonella. The results showed that the anti- Salmonella antibody with a dilution ratio of 1:500 can bind ~1700 Salmonella , and the binding rate reached to~70%. In terms of bacterial counts, vacuolar Salmonella dominates in the early stage of Salmonella infection, and cytosolic Salmonella dominates in the later stage, the reproduction rate of vacuolar Salmonella is significantly lower than cytosolic Salmonella during Salmonella infection, the dynamic growth curve of cytosolic Salmonella and vacuolar Salmonella intuitively reflected the proliferation status of the two forms of Salmonella during the entire process of Salmonella infection.
Salmonella infection
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Salmonella is capable of harming human and animal health, and its multidrug resistance (MDR) has always been a public health problem. In addition, antibiotic-free or antibiotic-reduced policies have been implemented in poultry production. Therefore, the search for antibiotic alternatives is more urgent than ever before. The aim of this study was to assess the antibacterial activity of star anise-cinnamon essential oil (SCEO) in vitro and its prophylactic effect against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in vivo. The results demonstrated that SCEO is effective against Salmonella pullorum, Salmonella give, and Salmonella kentucky in vitro. Supplementation with SCEO could significantly decrease the infections of Salmonella pullorum and Salmonella give, whereas it could slightly but not significantly decrease the infection of Salmonella kentucky, while also significantly alleviating the body weight (BW) loss caused by the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens. The SCEO had the best prophylactic effect against the infection of Salmonella give in Yellow chickens, followed by the infection of Salmonella pullorum and the infection of Salmonella kentucky. The SCEO, used as an antibiotic alternative, could be an effective prevention strategy against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens.
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The incidence of salmonella in turkeys from experimental salmonella-controlled and uncontrolled, or normal, flocks processed at three turkey slaughter plants were compared. The results indicate that processing salmonella-controlled turkeys in a plant that routinely kills normal birds may result in the contamination of the salmonella-controlled birds, probably due to salmonella in the plant environment. The salmonella-controlled turkeys studied tended to have a lower incidence of salmonella than normal birds. These observation indicate that salmonella control practices in turkey raising can result in a salmonella reduction in market birds even under existing commercial slaughter, evisceration, and cooling procedures.
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A total of 100 meat and poultry products samples were collected from shops and supermarkets in Aswan governorate; including 50 meat products samples and 50 poultry products.Samples were collected to determine the serotypes and antigenic structures of Salmonella isolates in meat and poultry products and to study the correlation between serotypes and type of meat.Salmonella was isolated by conventional methods and serotyping of Salmonella isolates was performed by slide agglutination method using antisera to Salmonella.It was observed that 16 % of samples were positive for Salmonella; 26% (13/50) in meat samples and 6% (3/50) in poultry samples.Serotypes of isolated Salmonella were Salmonella enteritidis 6.25% (1/16), Salmonella newland 18.75% (3/16), Salmonella Kentucky 12.5% (2/16), Salmonella heifa 6.25% (1/16), Salmonella bron 6.25% (1/16), Salmonella rissens 12.5% (2/16), Salmonella fortune 12.5% (2/16), Salmonella agona 6.25% (1/16), Salmonella hessarek 6.25% (1/16), Salmonella hoboken 6.25% (1/16), Salmonella veneziana 6. Meat and poultry products were contaminated with pathogenic Salmonella and the more prevalent serotypes were Salmonella newland, Salmonella rissens, Salmonella fortune, Salmonella Kentucky and the lesser prevalent isolates were Salmonella enteritidis, Salmonella heifa, Salmonella bron, Salmonella agona, Salmonella hessarek, Salmonella hoboken and Salmonella veneziana.Results showed that minced meat, kofta, liver and gizzard and sheeshtawook were more contaminated with Salmonellae.Meat and poultry products considered an important source of high risk serotypes of Salmonellae for human and hygienic measures should be undertaken to reduce contamination of meat and poultry products with Salmonella.
Poultry meat
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A microtitration plate, antibody-capture, enzyme-linked immunosorbent assay was developed for detection of Salmonella typhimurium. The assay utilizes a monoclonal detector antibody which shows no cross-reactions with non-Salmonella species and only a slight cross-reaction with one other Salmonella serotype. By using only one cultural stage (in a nonselective, chemically defined medium) prior to the enzyme-linked immunosorbent assay, low numbers of cells in food (10 cells 25 g-1) were detected in 19 h. Non-Salmonella competing organisms did not interfere with detection of S. typhimurium even when present in the ratio of 10(6):1 (non-Salmonella/Salmonella spp.). The assay shows the feasibility of rapid, 1-day testing for Salmonella spp. with antibody technology.
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