Academic literature on the topic 'Salmonella typhimurium ATCC 14028'

The use of direct PCR technique without DNA extraction in the confirmation test for Salmonella typhimurium ATCC 14028 bacteria on meatball samples was carried out in the Food and Drug molecular biology testing laboratory Administration in Gorontalo. The basis of this research is to have an impact on economic value in carrying out the confirmation test for S. typhimurium ATCC 14028, where testing is carried out conventionally, namely DNA extraction, which requires a large amount of money. Hence, it is necessary to innovate to modify the testing phase so that it is more effective and efficient. The purpose of this study was to see whether the direct PCR technique without DNA extraction can be done for the confirmation test of S. typhimurium ATCC 14028 on meatball samples. This study's sample consisted of 20 types of meatball samples spiked with S. typhimurium ATCC 14028 cultures. The method used in this study was qPCR analysis using the SYBR Green method. Data analysis was carried out based on 2 main criteria: (1) Ct analysis and (2) Tm analysis. Real-time PCR analysis results obtained Ct values ​​in the range 14.14 - 15.20 with an average of 14.82 and Tm values ​​85.20 - 86.30 with an average of 85.79. Based on these data, it can be concluded that using direct PCR can be used for testing confirmation of S. typhimurium ATCC 14028 on meatball samples.

The detection of Salmonella typhimurium ATCC 14028 using real-time PCR on powdered traditional medicinal products was carried out in the microbiology and molecular biology testing laboratory of the Food and Drug Administration in Gorontalo. This research aims to provide a reference for alternative testing methods in testing the products of traditional powder preparations on the market. The sample consisted of 10 traditional powder preparations spiked with positive control of S. typhimurium ATCC 14028 phase 2. The method used in the study was real-time PCR analysis using the SYBR® Green method, while DNA isolation using the direct PCR method. Data analysis was performed by analyzing the sample's melting temperature (Tm) curve and comparing it with positive control. The results showed that S. typhimurium ATCC 14028 was detected in samples at an average Tm value of 84.18°C, with ranges of 84.0-84.5°C. For positive control, the Tm value was at 85.2°C, while for the negative control, the Tm value was not detected. Based on these data, it can be concluded that S. typhimurium ATCC 14028 in traditional medicine products powder preparations can be detected using real-time PCR.

ABSTRACT Salmonella Typhimurium is a potential feed safety hazard in animal feed ingredients. Thermal mitigation of Salmonella spp. during rendering is effective but does not eliminate the potential for cross-contamination. Therefore, the objective of this experiment was to evaluate the effectiveness of chemicals to mitigate postrendering Salmonella Typhimurium ATCC 14028 contamination in rendered proteins over time. Treatments were arranged in a 6 ×4 factorial with six chemical treatments and four rendered protein meals. The chemical treatments included (i) control without chemical treatment, (ii) 0.3% commercial formaldehyde product, (iii) 2% essential oil blend, (iv) 2% medium chain fatty acid blend, (v) 3% organic acid blend, and (vi) 1% sodium bisulfate. The four rendered protein meals included (i) feather meal, (ii) blood meal, (iii) meat and bone meal, and (iv) poultry by-product meal. After matrices were chemically treated, they were inoculated with Salmonella Typhimurium ATCC 14028, stored at room temperature, and enumerated via plate counts on days 0, 1, 3, 7, 14, 21, and 42 postinoculation. The Salmonella concentration in ingredients treated with medium chain fatty acid and commercial formaldehyde were similar to one another (P =0.23) but were 2 log lower than the control (P < 0.05). Ingredients treated with organic acids and essential oils also had lower Salmonella concentrations than the control (P < 0.05). Time also played a significant role in Salmonella mitigation, because all days except days 14 and 21 (P = 0.92) differed from one another. Rendered protein matrix also affected Salmonella stability, because concentrations in meat and bone meal and blood meal were similar to one another (P =0.36) but were greater than levels in feather meal and poultry by-product meal (P < 0.05). In summary, chemical treatment and time both mitigated Salmonella Typhimurium ATCC 14028, but their effectiveness was matrix dependent. Time and chemical treatment with medium chain fatty acids or a commercial formaldehyde product were most effective at mitigating Salmonella Typhimurium ATCC 14028 in rendered protein meals.

Salmonella enterica as common pathogens of humans and animals are good model organisms to conduct research on bacterial biology. Because these bacteria can multiply in both the external environments and in the living hosts, they prove their wide adaptability. It has been previously demonstrated that prolonged exposition of Salmonella serotype O48 cells to normal human serum led to an increase in resistance to sera in connection with the synthesis of very long O-antigen. In this work, we have studied the phenotype connected to virulence of Salmonella enterica strains that were subjected to consecutive passages in 50% human serum from platelet-poor plasma (SPPP). We found that eight passages in SPPP may not be enough for the bacteria to become serum-resistant (S. Typhimurium ATCC 14028, S. Senftenberg). Moreover, C1q and C3c complement components bound to Salmonellae (S. Typhimurium ATCC 14028, S. Hammonia) membrane proteins, which composition has been changed after passaging in sera. Interestingly, passages in SPPP generated genetic changes within gene fljB, which translated to cells’ motility (S. Typhimurium ATCC 14028, S. Erlangen). One strain, S. Hammonia exposed to a serum developed a multi-drug resistance (MDR) phenotype and two S. Isaszeg and S. Erlangen tolerance to disinfectants containing quaternary ammonium salts (QAS). Furthermore, colonial morphotypes of the serum adaptants were similar to those produced by starter cultures. These observations suggest that overcoming stressful conditions is manifested on many levels. Despite great phenotypic diversity occurring after prolonged exposition to SPPP, morphotypes of colonies remained unchanged in basic media. This work is an example in which stable morphotypes distinguished by altered virulence can be confusing during laboratory work with life-threatening strains.

An increasing number of foodborne diseases are currently attributable to farm produce contaminated with enteric pathogens such as Salmonella enterica. Recent studies have shown that a variety of enteric pathogens are able to colonize plant surfaces by forming biofilms and thereby persist for long periods, which can subsequently lead to human infections. Therefore, biofilm formation by enteric pathogens on plants poses a risk to human health. Here, we deciphered the roles of YcfR in biofilm formation by Salmonella enterica. YcfR is a putative outer membrane protein associated with bacterial stress responses. The lack of YcfR facilitated the formation of multicellular aggregates on cabbage leaves as well as glass surfaces while reducing bacterial motility. ycfR deletion caused extensive structural alterations in the outer membrane, primarily in lipopolysaccharides, outer membrane proteins, cellulose, and curli fimbria, thereby increasing cell surface hydrophobicity. However, the absence of YcfR rendered Salmonella susceptible to stressful treatments, despite the increased multicellular aggregation. These results suggest that YcfR is an essential constituent of Salmonella outer membrane architecture and its absence may cause multifaceted structural changes, thereby compromising bacterial envelope integrity. In this context, YcfR may be further exploited as a potential target for controlling Salmonella persistence on plants.

Most studies on Salmonella enterica serovar Typhimurium infection focus on strains ATCC SL1344 or NTCC 12023 (ATCC 14028). We have compared the abilities of these strains to induce membrane ruffles and invade epithelial cells. S. Typhimurium strain 12023 is less invasive and induces smaller membrane ruffles on MDCK cells compared with SL1344. Since the SPI-1 effector SopE is present in SL1344 and absent from 12023, and SL1344 sopE mutants have reduced invasiveness, we investigated whether 12023 is less invasive due to the absence of SopE. However, comparison of SopE+ and SopE− S. Typhimurium strains, sopE deletion mutants and 12023 expressing a sopE plasmid revealed no consistent relationship between SopE status and relative invasiveness. Nevertheless, absence of SopE was closely correlated with reduced size of membrane ruffles. A PprgH–gfp reporter revealed that relatively few of the 12023 population (and that of the equivalent strain ATCC 14028) express SPI-1 compared to other S. Typhimurium strains. Expression of a PhilA–gfp reporter mirrored that of PprgH–gfp in 12023 and SL1344, implicating reduced signalling via the transcription factor HilA in the heterogeneous SPI-1 expression of these strains. The previously unrecognized strain heterogeneity in SPI-1 expression and invasiveness has important implications for studies of Salmonella infection.

ABSTRACT Loss of the Salmonella MsbB enzyme, which catalyzes the incorporation of myristate destined for lipopolysaccharide in the outer membrane, results in a strong phenotype of sensitivity to salt and chelators such as EGTA and greatly diminished endotoxic activity. MsbB− salmonellae mutate extragenically to EGTA-tolerant derivatives at a frequency of 10−4 per division. One of these derivatives arose from inactivation of somA, which suppresses sensitivity to salt and EGTA. Here we show that a second mode of MsbB− suppression is a RecA-dependent deletion between two IS200 insertion elements present in Salmonella enterica serovar Typhimurium strain ATCC 14028 but not in two other wild-type strains, LT2 and SL1344, which lack one of the IS200 elements. This deletion occurs spontaneously in wild-type and MsbB− strain 14028 salmonellae and accounts for about one-third of all of the spontaneous suppressors of MsbB− in strain 14028. It spans the region corresponding to 17.7 to 19.9 centisomes, which includes somA, on the sequenced map of Salmonella LT2 (136 ORFs in that strain; ATCC 14028 and other strains showed variability in this region). In addition to conferring EGTA resistance correlated with somA, the deletion confers a MacConkey galactose resistance phenotype on MsbB− Salmonella, indicating that at least one additional gene (distinct from somA) within the deletion is responsible for this phenotype. In the wild type, the deletion mutant grows with normal exponential growth rate in Luria broth but is chlorate resistant and does not grow on citrate agar. The deletion strains have lost hydrogen sulfide production, nitrate reductase activity, and gas production from glucose fermentation.

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.

In vitro laboratory studies were performed to assess the effects of antecedent growth conditions on the recovery of Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028 following chloramine disinfection. Six- and 18-h cultures of each organism were grown under aerobic, fermentative, and nitrate-reducing conditions prior to disinfection. At predetermined time intervals during a 10-min exposure to chloramine, survivors were surface plated on nonselective recovery media to determine Cnt values. It was observed that nitrate-reducing growth predisposed the test organisms towards an increased sensitivity to chloramine stress over cells grown under fermentation or aerobic conditions (p < 0.01).Key words: Escherichia coli, Salmonella typhimurium, chloramine, survival, antecedent growth conditions.

Gastrointestinal probiotics are important members of intestinal microflora in both healthy animals and human beings, and these bacteria may reduce the risk of infection caused by certain opportunistic pathogens through exclusive inhibition, competition, and displacement. The lp_1643 protein on the cell surface of Lactobacillus plantarum WCFSI was assumed to possess a mucus-binding capability. This study aimed to determine if purified His-N2 protein exclusively inhibits pathogen adhesion to porcine mucus. The interaction of the His-N2 protein with porcine mucus was determined by indirect enzyme-linked immunosorbent assay (ELISA), and the adhesion was assessed by a traditional plating method to count the bacteria adhered to the porcine mucus. Indirect ELISA showed that His-N2 protein adhered to porcine mucus, and its interacting molecules existed. The His-N2 protein effectively inhibited the adhesion of Escherichia coli DH5α, Listeria monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and Shigella flexneri CMCC(B)51572 to porcine mucus. Results showed that inhibition of pathogen adhesion to porcine mucus depended on dose and strain. The adhesion of L. monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and S. flexneri CMCC(B)51572 was reduced by 95.7, 97.0, and 95.7%, respectively, by pre-adding 100 μl of 3.92 mg/ml of His-N2 protein, whereas that of E. coli DH5α was only 50.4%. The inhibition of adhesion of some pathogens by His-N2 was different at pH 6.6 and 7.5. The inhibition of E. coli DH5α, L. monocytogenes CMCC54004, and Salmonella Typhimurium ATCC 14028 at pH 6.6 was significantly higher than that at pH 7.5, whereas no statistically significant difference was observed in S. flexneri CMCC(B)51572. These results suggest that various types of inhibition mechanisms of His-N2 were involved in different pathogens.

Rapid detection of pathogens and hazardous elements in fresh fruits and vegetables after harvest requires the use of advanced sensor technology at each step in the farm-to-consumer or farm-to-processing sequence. Fourier-transform infrared (FTIR) spectroscopy and the complementary Raman spectroscopy, an advanced optical technique based on light scattering will be investigated for rapid and on-site assessment of produce safety. Paving the way toward the development of this innovative methodology, specific original objectives were to (1) identify and distinguish different serotypes of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Bacillus cereus by FTIR and Raman spectroscopy, (2) develop spectroscopic fingerprint patterns and detection methodology for fungi such as Aspergillus, Rhizopus, Fusarium, and Penicillium (3) to validate a universal spectroscopic procedure to detect foodborne pathogens and non-pathogens in food systems. The original objectives proposed were very ambitious hence modifications were necessary to fit with the funding. Elaborate experiments were conducted for sensitivity, additionally, testing a wide range of pathogens (more than selected list proposed) was also necessary to demonstrate the robustness of the instruments, most crucially, algorithms for differentiating a specific organism of interest in mixed cultures was conceptualized and validated, and finally neural network and chemometric models were tested on a variety of applications. Food systems tested were apple juice and buffer systems. Pathogens tested include Enterococcus faecium, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Yersinia enterocolitis, Shigella boydii, Staphylococus aureus, Serratiamarcescens, Pseudomonas vulgaris, Vibrio cholerae, Hafniaalvei, Enterobacter cloacae, Enterobacter aerogenes, E. coli (O103, O55, O121, O30 and O26), Aspergillus niger (NRRL 326) and Fusarium verticilliodes (NRRL 13586), Saccharomyces cerevisiae (ATCC 24859), Lactobacillus casei (ATCC 11443), Erwinia carotovora pv. carotovora and Clavibacter michiganense. Sensitivity of the FTIR detection was 103CFU/ml and a clear differentiation was obtained between the different organisms both at the species as well as at the strain level for the tested pathogens. A very crucial step in the direction of analyzing mixed cultures was taken. The vector based algorithm was able to identify a target pathogen of interest in a mixture of up to three organisms. Efforts will be made to extend this to 10-12 key pathogens. The experience gained was very helpful in laying the foundations for extracting the true fingerprint of a specific pathogen irrespective of the background substrate. This is very crucial especially when experimenting with solid samples as well as complex food matrices. Spectroscopic techniques, especially FTIR and Raman methods are being pursued by agencies such as DARPA and Department of Defense to combat homeland security. Through the BARD US-3296-02 feasibility grant, the foundations for detection, sample handling, and the needed algorithms and models were developed. Successive efforts will be made in transferring the methodology to fruit surfaces and to other complex food matrices which can be accomplished with creative sampling methods and experimentation. Even a marginal success in this direction will result in a very significant breakthrough because FTIR and Raman methods, in spite of their limitations are still one of most rapid and nondestructive methods available. Continued interest and efforts in improving the components as well as the refinement of the procedures is bound to result in a significant breakthrough in sensor technology for food safety and biosecurity.