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Background: Salmonella enterica serovar typhi (S. typhi) the cause of the acute febrile disease typhoid fever is the major public health problem in developing countries. Asymptomatic carriers are the main sources of typhoid. The aim of this study was to investigate methods for isolation and identification of S. typhi in asymptomatic carriers.
Materials and Methods: Two hundred stool samples were collected from foodstuff workers and distributors. Then culture characterization, biochemical tests, and nested-PCR were done.
Results: One hundred and seventy-one (85%) of the total cases were male and the mean age of cases was 35 years. Stool culture yielded bacterial colonies consistent with fecal flora but did not yield S. typhi. In nested PCR technique just one of the 200 samples (0.5%) was positive for the S. typhi capsular gene (vi gene).
Conclusion: Due to the improvement in the health status of the country and the low typhoid carriers, it is recommended that efforts be focused on other hygienic issues.

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Background: Salmonella typhimurium is one of the most important species of Salmonella that is intracellular parasite and attacks host mucus membrane. These bacteria can cause gastroenteritis, and their main transmission route is water, poultry, meat, egg, and raw food. The aim of this study was to detect three virulence genes associated with S. typhimurium named invA, STM4497, and fliC183 genes by Multiplex PCR method.
Materials and Methods: 183 samples of poultry were collected from food products in Zanjan (Iran) and cultured in BPW (Buffered Peptone Water) for 18 hr and at 37°C, and in RVS broth (Rappaport Vassiliadis Soya) for 6 hr at 41.5°C. After amplification of genomic DNA by Multiplex PCR method, occurrence of pathogen contamination was checked and compared with standard strain.
Results: From the total of 183 collected samples, 52(28.4%) samples were positive for S. typhimurium. The frequency of STM4497, fliC183, and invA genes were 49 (27%), 3 (2%), and 53 (29%), respectively.
Conclusion: Simultaneous detection of invA, STM4497, and fliC183 genes were recognized as a key for detection of S. typhimurium by Multiplex PCR method. 

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Protein hydrolysate (PH) from viscera of cultured Siberian sturgeon (Acipenser baerii) was produced. To optimize the production conditions, Response Surface Method (RSM) was employed to examine the effects of three different operating conditions, including time, pH, and enzymatic concentration (Alcalase) on the degree of hydrolysis.The mathematical model showed acceptable fitness of the experimental data as R2 equaled 0.97, which indicated  that   major part of  the  variability  within  the  range  of  values could  be explained  by  the  model. The results showed that the highest degree of hydrolysis (58.21%) was related to the treatment which happened at the enzymatic concentration of 2%, 60 minutes time, and pH=8. Treatment under hydrolysis condition (i.e., E/S = 2%, Time = 45 min, and pH = 8.5) had the highest protein content (42.37g/l), which was used as an alternative to commercial peptone medium (Triptic soy broth) to assess the growth of Salmonella typhi bacteria from 0 to 48 hours. Although there was an upward trend in growth rate of S. typhi both in control and No. 15 (Alcalase) treatments, the log growth of control treatment was found to be better than that of Alcalase treatment. However, there existed no significant difference between the two treatments.

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Background: Foodborne diseases caused by Salmonella are considered as a global health concern, especially in low-income countries. Rapid and specific detection of this infective agent is highly important in the outbreak control. The current study aimed to design and optimize a LAMP method and to compare its sensitivity and efficiency with the PCR method in the detection of S. typhi in food.
Materials & Methods: Food samples including mayonnaise and vegetable salad were inoculated with S. enterica serovar Typhi. Sensitivity and detection limit of LAMP test were investigated at different concentrations of contaminated mayonnaise and vegetable salad. invA gene was chosen as the target gene for bacterial detection by PCR and LAMP tests.
Findings: The detection limit of Samonella was estimated to be 16 CFU/mL using LAMP and PCR. LAMP reaction revealed a visible turbidity, indicating the accurate amplification of the selected target gene and proper identification of Salmonella at different dilutions of the studied food samples.
Conclusion: The present study indicated that LAMP is a rapid, cost-effective, and specific technique for the identification of Salmonella. This method could be used in laboratories with minimal equipment without the need for costly molecular detection methods.

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Objectives: Salmonella typhimurium is important food-borne pathogen responsible for gastroenteritis. In this work a polymerase chain reaction based enzyme linked immunosorbent assay (PCR-ELISA) was developed to identify Salmonella typhimurium. Materials and Methods: The rfb gene which is responsible for biosynthesis of the Salmonella O-antigenic lipopolysaccharide was selected as the target sequence. The selected primers amplified fragment size of 882bp of S. typhimurium. Food samples contaminated with Salmonella typhimurium as well as clinical and standard samples were used in this investigation. The PCR products randomly labeled with Dig-11-dUTP were transformed to a plate coated with streptoavidin and tested with anti digoxigenin. An internal biotin-labeled probe was used to confirm the amplified PCR product. Results: The specificity of the assay toward S.typhimurium samples was confirmed by testing 20 Salmonella and 6 non Salmonella strains. ELISA increased the sensitivity of the conventional PCR method by approximately 1000 fold. Conclusion: The method presented here is a rapid and specific alternative for the traditional time consuming culture methods for the detection of S. typhimurium in food and clinical samples. Due to its high specificity and sensitivity, our method finds its place as an alternative to PCR in large scale screenings, for detection of S. typhimurium.

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In recent years, the attention of researchers to common diseases between humans and animals (zoonosis), control of diseases and food poisoning of animal origin has been very high. Due to the importance of meat in the transmission of pathogenic bacteria such as Salmonella, in this study, the control and reduction of microbial load of this dangerous bacterium was studied using Ziziphora clinopodioides essential oil (ZEO) in vitro. First, the Ziziphora clinopodioides plant was prepared and its essential oil was extracted using an industrial clevenger apparatus. Essential oil compositions were obtained by chemical analysis using GC/MS. The results of the chemical analysis showed that Pulegone is the most abundant compound in ZEO. Antibacterial effects of ZEO on Salmonella typhimurium and Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by tube dilution method. Experimental results show that ZEO has an antimicrobial effect on Salmonella typhimurium and can be added to food as a natural preservative. The Minimum Inhibitory Concentration (MIC) of ZEO for Salmonella typhimurium was 125 µL/L and the Minimum Bactericidal Concentration (MBC) of ZEO for Salmonella typhimurium was 250 µL/L.

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Background and target: Salmonella typhimurium is a gram-negative rod-forming bacterium belonging to the family Enterobacteriaceae and Is one of the most common foodborne pathogens, that With several pathogenic factors, including toxins, Secretory proteins, and secretory system T3SS(That Causes fluid secretion And inflammation), Etc It can a suitable candidate for this stud. The purpose of this study, Evaluation of the cytotoxicity effect of bacterial protein fractions on growth and proliferation of melanoma cancer cells, which is the most resistant type of skin cancer.
materials and methods: In this experimental study, the cancer cell line (BL16) melanoma was used. Different bacterial fractions were prepared by the ammonium sulfate method. Interaction of cancer cells with different concentrations of Salmonella typhimurium fractions was studied. Cell proliferation was assessed by MTT assay at 24 and 48 hours.
findings: MTT test results with fractions (Bacteria lysate in culture medium, 80% deposition of lysate proteins, 30% deposition of lysate proteins, 80% deposition on culture media, and 30% deposition on culture media) The highest effect was observed at concentrations of 9.25,30, 8, 72, 10.75 μg / ml, respectively.
Discussion and conclusion: Results show that bacterial fractions of Salmonella typhimurium have high toxicity and lethal effect on melanoma cancer cells. These compounds can be suggested and used as an alternative or complementary to cancer therapy.