Salmonella Typhimurium Research Articles

Integrated Metagenomic and Metabolomics Profiling Reveals Key Gut Microbiota and Metabolites Associated with Weaning Stress in Piglets.

(1) Background: Weaning is a challenging and stressful event in the pig's life, which disrupts physiological balance and induces oxidative stress. Microbiota play a significant role during the weaning process in piglets. Therefore, this study aimed to investigate key gut microbiota and metabolites associated with weaning stress in piglets. (2) Methods: A total of ten newborn piglet littermates were randomly assigned to two groups: S (suckling normally) and W (weaned at 21 d; all euthanized at 23 d). Specimens of the cecum were dehydrated with ethanol, cleared with xylene, embedded in paraffin, and cut into 4 mm thick serial sections. After deparaffinization, the sections were stained with hematoxylin and eosin (H&E) for morphometric analysis. Cecal metagenomic and liver LC-MS-based metabolomics were employed in this study. Statistical comparisons were performed by a two-tailed Student's t-test, and p < 0.05 indicated statistical significance. (3) Results: The results showed that weaning led to intestinal morphological damage in piglets. The intestinal villi of suckling piglets were intact, closely arranged in an orderly manner, and finger-shaped, with clear contours of columnar epithelial cells. In contrast, the intestines of weaned piglets showed villous atrophy and shedding, as well as mucosal bleeding. Metagenomics and metabolomics analyses showed significant differences in composition and function between suckling and weaned piglets. The W piglets showed a decrease and increase in the relative abundance of Bacteroidetes and Proteobacteria (p < 0.05), respectively. The core cecal flora in W piglets were Campylobacter and Clostridium, while those in S piglets were Prevotella and Lactobacillus. At the phylum level, the relative abundance of Bacteroidetes significantly decreased (p < 0.05) in weaned piglets, while Proteobacteria significantly increased (p < 0.05). Significant inter-group differences were observed in pathways and glycoside hydrolases in databases, such as the KEGG and CAZymes, including fructose and mannose metabolism, salmonella infection, antifolate resistance, GH135, GH16, GH32, and GH84. We identified 757 differential metabolites between the groups through metabolomic analyses-350 upregulated and 407 downregulated (screened in positive ion mode). In negative ion mode, 541 differential metabolites were identified, with 270 upregulated and 271 downregulated. Major differential metabolites included glycerophospholipids, histidine, nitrogen metabolism, glycine, serine, threonine, β-alanine, and primary bile acid biosynthesis. The significant differences in glycine, serine, and threonine metabolites may be potentially related to dysbiosis caused by weaning stress. Taken together, the identification of microbiome and metabolome signatures of suckling and weaned piglets has paved the way for developing health-promoting nutritional strategies, focusing on enhancing bacterial metabolite production in early life stages.

Single and combined effects of oregano leaf and clove oils on the reduction of salmonella enteritidis on chicken egg shells

Table eggs are versatile foodstuffs used in various food products. Eggs are often consumed or incorporated into other food products to enhance taste and nutrition and act as an emulsifying agent. Too often the consumption of contaminated eggs leads to foodborne illnesses in people. When whole eggs or egg products come into contact with contaminated surfaces or other contaminated eggs, pathogens can spread from one egg to another. Research has been conducted to uncover ways to protect whole eggs and their products from contamination by coating the egg’s exterior with edible coatings. Mineral oil, among other edible oils, is one such oil shown to be effective in reducing the bacteria in eggs when applied to the egg’s exterior. With the average consumer becoming more aware of the chemicals used in the preservation of food, some researchers have started to explore more natural solutions to minimize the contamination of food products. The use of essential oils to prevent contamination has been studied and analyzed for their antimicrobial properties in the inhibition of the growth of foodborne pathogens. The oils used in this current study are Oregano and Clove Oil. Both oils used individually and combined compared to a positive control showed no differences (p &gt; 0.05). Interestingly, when the oils were combined 1:1 there was a difference of 0.66 log in the survival bacterial counts compared to the positive control. However, this difference was also not significant (p &gt; 0.05).

Characterization of spray-dried plasma-induced immune response in Salmonella-challenged broiler chicks

Spray-dried plasma (SDP) is a functional feed additive that has been established to improve performance and health of livestock. Understanding the effect of SDP in immune response modulation is essential to optimize its use for controlling Salmonella Enteritidis (SE) infection in chickens. This study was conducted to determine the levels of expression of selected cytokine genes in the ileum and cecal tonsil of SE-challenged broiler chicks. In a floor-pen housing, 320 broilers chicks were randomly assigned to 6 treatment groups: CX (unmedicated corn-soybean meal (SBM) basal without SDP), MX (unmedicated corn-SBM basal with antibiotic bacitracin methylene disalicylate (BMD) added at 0.055g/kg diet), PCX (unmedicated corn-SBM basal with SDP added at 30g/kg diet). Treatments SE, MSE, and PSE consisted of chicks inoculated with 7.46 × 108 CFU SE /mL at 1 d of age and given diets similar to CX, MX, and PCX, respectively. Samples of cecal tonsils and ileum were collected on d 3, 7 and 14 post infection for qRT-PCR analysis to determine the expression levels of interleukin (IL)-1β, interferon-γ (IFN-γ), IL-13, IL-17, IL-6, and transforming growth factor (TGF)-β genes. In the ceca tonsils, expression of IFN-γ was not affected by the interaction of Day and Treatment (P > 0.05). The level of the anti-inflammatory cytokine IL-13 was lower in MX and PCX on d 7 whereas high levels were expressed (P < 0.05) in MSE and PSE. In the ileum, expression of IL-17 and IFN-γ was significantly lower (P < 0.05) in PSE and MSE, but only PSE expressed lower IL-6 comparable to unchallenged treatments. On d 28 postchallenge, concentrations of anti-SE IgY and IL-6 protein were higher (P < 0.05) in the SE-challenged treatments compared to the unchallenged treatments. Overall, these results suggest that dietary SDP showed similar potency to BMD in modulating intestinal cytokine response against intestinal SE colonization in broiler chicks and therefore can be considered suitable alternative replacement for antibiotics in broiler production.

Positive salmonella enterica faecal surveillance samples in an equine veterinary teaching hospital: 2021–2023

Positive salmonella enterica faecal surveillance samples in an equine veterinary teaching hospital: 2021–2023

Identification of lysosome-related hub genes as potential biomarkers and immune infiltrations of moyamoya disease by multiple bioinformatics methods and machine-learning strategies

BackgroundMoyamoya disease (MMD), characterized by chronic cerebrovascular pathology, poses a rare yet significant clinical challenge, associated with elevated rates of mortality and disability. Despite intensive research endeavors, the exact biomarkers driving its pathogenesis remain enigmatic. MethodsThe expression patterns of GSE189993 and GSE141022 were retrieved from the Gene Expression Omnibus (GEO) repository to procure differentially expressed genes (DEGs) between samples afflicted with MMD and those under control conditions. The Least Absolute Shrinkage and Selection Operator (LASSO), Support Vector Machine with Recursive Feature Elimination (SVM-RFE), and Random Forest (RF) algorithms were employed for identifying candidate diagnostic genes associated with MMD. Subsequently, these candidate genes underwent validation in an independent cohort (GSE157628). The CMAP database was ultimately employed to forecast drugs pertinent to MMD for clinical translation. ResultsA collective of 240 DEGs were discerned. Functional enrichment scrutiny unveiled the enrichment of the cholesterol metabolism pathway, salmonella infection pathway, and allograft rejection pathway within the MMD cohort. EPDR1, DENND3, and NCSTN emerged as discerned diagnostic biomarkers for MMD. The CMAP database was ultimately employed to scrutinize the ten most auspicious pharmaceutical compounds for managing MMD. Finally, after validation through in vitro experiments, EPDR1, DENND3, and NCSTN were identified as the key genes. ConclusionEPDR1, DENND3, and NCSTN have emerged as potential novel biomarkers for MMD. The involvement of T lymphocytes, neutrophilic granulocytes, dendritic cells, natural killer cells, and plasma cells could be pivotal in the pathogenesis and advancement of MMD.

The “Baseline Widal Titre” Amongst Apparently Healthy Adults Working at a Tertiary Care Medical Institution, a Pilot Study, Uttarakhand, India

Introduction: As typhoid fever is known for its endemicity all over the India, healthy people may contain antibodies against salmonella typhi and paratyphi. These antibodies may react up-to a variable titre either due to past exposure, vaccination or/and cross -reacting antigen. Therefore, antibody titre in widal test varies widely from place to place and is referred as baseline titre of that particular area. Two properly staged tests (2-4 weeks interval) show about a four -fold rise in antibody levels leads to a reliable widal test. Single widal test values are not considered significant for diagnosis but many places still use this as diagnostic marker which further depends upon baseline titre prevalent in that particular area. Aims: This study was undertaken in jhajra, Uttarakhand to determine the baseline titre in this geographical region for calculating significant widal titres. Material and Methods: Blood samples were collected from apparently healthy individuals which included medical students, nursing staff, doctors, and other health care workers (aged 19-45) with proper consent. All the samples after being screened by slide agglutination test were further confirmed by Quantitative tube agglutination test, to find out the baseline titre. The tube agglutination test was carried out by taking 0.5 ml of two-fold serially diluted sera (dilutions from 1:20 to 1:320) in 0.9% normal saline with an equal amount of antigen. Results: Out of total 110 serum samples,36 (32.7%) sera were positive (titre ≥ 1:20) and 74 (67.3%) were negative(titre&lt;1:20). A total of 36 samples were positive for agglutinins of “O” antigen,32 for agglutinins of “H” antigen,16 for paratyphi A and 10 for paratyphi B. 23 out of 36 (63.8 %) sera were positive for agglutinins of 'O' antigen of Salmonella typhi (TO) at a titre of 1:40 followed by 6 sera positive at 1:20 (16.6%) and 1:80 (16.6%) and 1 serum sample positive at 1:160 (2.77%) 59.3 % (19) sera were positive for 'H' antigen of Salmonella typhi (TH) at a titre of 1:80 and 10 % sera (11) were positive for 'H' antigen at a titre of 1:40 and 2(1.8%) were positive at 1:20.16(44.4%) sera samples were positive for of Salmonella paratyphi A (AH) and Salmonella paratyphi B (BH) respectively, both at a titre of 1:20 and 8.3% sera were positive at 1:40 respectively. Conclusion: The most frequently recorded titre of the reactive sera was 1:40 and 1:80 for anti-O antibodies and anti-H antibodies and 1:20 for AH and BH. Thus, the significant cut-off level for TO and TH was ≥ 1:80 and ≥ 1:160 that for AH and BH was ≥ 1:40.

The results of epidemiological analysis of salmonellosis incidence in the Rostov region under current conditions

Objective: to study the features of the epidemic process of salmonella infection under current conditions. To establish a causal relationship between the incidence of salmonellosis and the functioning of public catering enterprises, which can form the epidemiological risks.Materials and methods: to assess the intensity, dynamics and structure of the epidemic process of salmonella infection, methods of operative and retrospective epidemiological analysis used, to identify and characterize etiological agents — laboratory methods: bacteriological, serological, molecular genetic analysis.Results: in the course of the study, the epidemiological features of the spread of salmonellosis in the Rostov region were established, the main risks which can form multiple foci were determined on the example of a specific epidemic situation: the possible source of infection, pathways and transmission factors, the etiological agent — Salmonella enteritidis gr. O:9 (D1). Gross violations of sanitary legislation in organizing the work of a public catering enterprise caused a wide contamination of finished culinary goods by pathogens of salmonella infection.Conclusion: based on the identified features of the epidemic process, a complex of measures developed; the focus of infection localized and eliminated. Recommendations for the prevention of salmonellosis for workers in objects of a similar profile and the population are given.

Prevalence of Salmonella Typhi in Bile of the Patients Undergoing Cholecystectomy at a Tertiary Care Hospital Karachi

Objective: To estimate the prevalence of salmonella typhi in bile specimens collected from patients undergoing cholecystectomy at a tertiary care Hospital Karachi. Methodology: The descriptive cross-sectional study, was conducted at Department of Surgical Unit 21, Jinnah Postgraduate Medical Center, Karachi, from January 2021 to June 2021. Patients with symptomatic Cholelithiasis like sudden pain in the upper right portion of your abdomen which radiate towards right shoulder, nausea, vomiting, undergo cholecystectomy of either gender male or female with age 14 to 60 years were included. After open cholecystectomy, bile was aspirated from the gallbladder at fundus in five ml syringe and long spinal needles was used in case of laparoscopic cholecystectomy to collect bile under vision of telescope. Specimens were sent to laboratory according to protocol for culture sensitivity. Results: A total of 171 patients who met the inclusion and exclusion criteria were included. Mean age of the patients was 49.39±8.78 years. 83 (48.5%) were male and 88 (51.5%) were female. Prevalence of salmonella typhi in bile specimens collected from patients undergoing cholecystectomy, was found 17.54%. Furthermore, the frequency of salmonella isolate was statically insignificant according to the patient’s gender, diabetes and obesity (p=&gt;0.05), while it was statically significant according to age up to 40 years and residence in rural areas (p-&lt;0.05. Conclusion: A significant proportion of patients were found to have Salmonella in bile from patients undergoing cholecystectomy. Therefore, close monitoring of patients must be done in all patients with regular follow-up.

Synergistic Effect of Pakistani Honey with Black Seeds against Food Borne Pathogens

Background: Food borne infections is a major public health problem all over the world. For centuries, honey has been used as a gastrointestinal and topical remedy and also as a food preservative. It has been exploited not only as a food but, utilized for multiple purposes such as for the treatment of various disease, for wound healing etc. Black seeds have also been used in traditional medicine and food preservation due to their effective therapeutic properties. The synergy-based combination of both the herbal extracts may enhance the antimicrobial potential against food borne pathogens. Objective: This study aims to evaluate the antibacterial potential of different variants of Pakistani honey (Acacia honey, Ziziphus honey, and Sidr honey) in combination with black seeds against foodborne pathogens. Methods: The antibacterial activity of different Pakistani honey (Acacia honey, Ziziphus honey, and Sidr honey) was evaluated using an agar well diffusion assay. The synergistic effect of honey and black seed was also examined. Moreover, the Minimum Inhibitory Concentration (MIC) was determined using the tube dilution method. Results: The combination of Ziziphus honey and black seeds showed the most significant antibacterial effect such as 25.0, 28.0- and 30.0-mm zones of inhibition against Escherichia coli, Salmonella typhi, and Staphylococcus aureus respectively. The inhibition zone of the synergistic antibacterial effect of honey and black seed extracts against foodborne pathogens was significantly larger than the extracts used separately. Furthermore, the lowest MIC was observed 3.12 mg/ml against Escherichia coli and Staphylococcus aureus in the combination of Ziziphus honey with black seeds whereas, 6.25 mg/ml was observed against salmonella typhi. Conclusion: The present finding supports the traditional use of these different Pakistani honey variants in combination with black seeds for treating food borne pathogens to promote good health without any adverse side effects. The results suggested that present combination of natural extracts could be further explored clinically as a potent synergy-based therapeutic approach for treating various multidrug resistant food pathogens.

Dysregulation of stress erythropoiesis and enhanced susceptibility to Salmonella Typhimurium infection in AhR-deficient mice.

By acting as an environmental sensor, the ligand-induced transcription factor aryl hydrocarbon receptor (AhR) regulates acute innate and adaptive immune responses against pathogens. Here, we analyzed the function of AhR in a model for chronic systemic infection with attenuated Salmonella Typhimurium (STM). WT and AhR-deficient mice were infected with the attenuated STM strain TAS2010 and analyzed for bacterial burden, host defense functions and inflammatory stress erythropoiesis. AhR-deficient mice were highly susceptible to TAS2010 infection compared with WT mice demonstrated by reduced bacterial clearance and increased mortality. STM infection resulted in macrocytic anemia and enhanced splenomegaly along with destruction of the splenic architecture in AhR-deficient mice. In addition, AhR-deficient mice displayed a major expansion of splenic immature red blood cells, indicative of infection-induced stress erythropoiesis. Elevated serum levels of erythropoietin and interleukin-6 upon infection as well as increased numbers of splenic stress erythroid progenitors already in steady state probably drive this effect and might cause the alterations in splenic immune cell compartments, thereby preventing an effective host defense against STM in AhR-deficient mice. AhR-deficient mice fail to clear chronic TAS2010 infection due to enhanced stress erythropoiesis in the spleen and accompanying destruction of the splenic architecture.

Serum inflammatory cytokine IL-4 and IL-18 Levels in Patients with Typhoid Fever in Baghdad

Background: Gram-negative Salmonella enterica serotype typhi, or S. typhi, is intracellular bacteria belong to Enterobacteriaceae family that infect humans and cause Salmonellosis (typhoid fever), or (enteric fever), this disease is a major public health problem and a life-threatening bacterial infection in developing countries. Every year, there are thought to be between 12 and 33 million cases of typhoid fever, which leads to over 600,000 deaths. Specific immunity both humoral and cellular specific immune response activated to control Salmonella infection. This study aimed evaluate the function of IL-4 and IL18 levels as a diagnostic aid for this infection. Material and methods: Ninety suspected patients with typhoid fever diagnosed by specialist according to sign and symptom and thirty apparently healthy control where enrolled during the study period from September 2023 to February 2024. Blood was taken from both groups (5ml) and serum were gathered using centrifugation (3000 rpm for 5 min) and kept frozen in three Eppendorf for detection of serum IgM, IgG, IL-4 and IL-18 levels. Results: the result showed that out of 90 blood samples only 60 samples were positive to salmonella infection (confirmed by detecting specific salmonella IgM and IgG antibodies using ELIZA kits Sunlong biotech\China). Serum levels of IL-4, and IL18 (pg/ml) was measured in positive samples using ELIZA kits (Cloud-clone corp \USA). There is a significant increase in the level of IgM (0.33 ± 0.13) (mg\dl) and IgG (0.27 ± 0.1) (mg\dl) as compared to the control group in patients (0.16±0.03 and 0.12±0.03) (mg\dl) respectively with P &lt; 0.01, and there was a significant increase in the average IL-4 (334.00 ± 87.49) (pg/ml) and IL-18 level in patients (380.44 ± 68.95) (pg/ml) compared to the control group (83.40 ± 17.44 and 189.66 ± 70.40) (pg/ml) respectively with P &lt; 0.001. The results indicated a direct correlation between IL-4 and IL-18 serum levels with high level of serum IgM antibody compared to their levels in control group.

Short communication: Effects of a commercial triple-strain Bacillus-based probiotic on cecal colonization with Salmonella Enteritidis in commercial layer pullets

A commercial triple-strain Bacillus-based probiotic was tested to determine its effect on the colonization of the ceca by Salmonella Enteritidis (SE) in commercial layer pullets. Two treatments were tested, each with containing 128 day-of-hatch LSL layer chicks. On top of a standard diet: 1) no supplement (Control, CON), and 2) Probiotic (GalliPro® Fit, 500 g/MT, 1.6 × 106 CFU/g of finished feed, PRO). Environmental swabs were collected from each treatment group and tested to ensure freedom from SE prior to challenge. At 21 days of age, the SE challenge strain was administered orally at a dose of 3.3 × 108 CFU/bird. Pullets from each treatment group (n=32) were euthanized at 6-, 10-, 14-, and 18-days post infection (dpi). Contents from the ceca were aseptically collected and assessed for presence and abundance of SE. No differences in the prevalence of SE positive ceca following oral inoculation (P>0.05) were observed between treatment groups at 6-, 10-, 14-, or 18-dpi. Counts of SE in the ceca of the PRO group were not significantly different (P>0.05) from those of CON at 6- or 10-dpi. However, significantly lower counts of SE in the ceca of the PRO group were observed at 14-dpi (P<0.05) and 18-dpi (P<0.05) compared with CON. SE counts were 1.24 and 1.34 logs lower than CON at 14- and 18-dpi, respectively. In conclusion, supplementation of the triple-strain Bacillus-based probiotic resulted in lower cecal counts of SE compared to those that did not receive an effective probiotic, thereby reducing the risk of foodborne pathogens prior to harvest through sustainable, natural methods.

Effect of Pergularia daemia (Forssk) and Momordica charantia L. (bitter gourd) leaf extracts on some enteric bacterial species

Medicinal plants are potential sources of new antimicrobial molecules. This study was undertaken to determine the effects of Pergularia daemia (Forssk) and Momordica charantia (bitter gourd) leaf extracts on some enteric bacterial species. Plant leaves were collected from Kerker village of Jos East Local Government Area of Plateau State. Plants were identified, the leaves were shade-dried, pulverized into fine powder. Proximate analysis was carried out using AOAC methods. Extracts were obtained through cold maceration techniques. The extracts were used for phytochemical screening; antibacterial activity was carried out using well diffusion methods. Minimum inhibitory concentration and maximum bactericidal concentration was determined using broth dilution method. The results of proximate analysis showed that the plants powder were rich in carbohydrates, M. charantia 55.59± 0.02 and P. daemia 31.38 ± 0.03, followed by crude fiber and crude fat 19. 62± 0.04 and 16.69± 0.22 in P. daemia compared to 10.66 ± 0.03 and 10.78± 0.03 in M. charantia while ash content and moisture were moderate with 12.86±0.12 in M. charantia and 7.53 ± 0.02 in P. daemia. The phytochemicals showed the presence of alkaloids, phenols, flavonoids, tannins and terpenoids in all plant extracts. The antibacterial activity showed that the extracts have a broad spectrum of activity on the test organisms as compared to the standard drug gentamicin. There was a significant difference at p&lt;0.05. Shigella flexneri was the most susceptible to methanolic and aqueous extracts with 22.53± 0.10 at 500 mg/ml as compared to standard drug gentamicin 32.33± 0.18, followed by E. coli with 21.13± 0.13 at 500 mg/ml as compared to the control 29.60±0.15 and Salmonella typhi with 20.47±0.14 at the concentration of 500 mg/ml as compared to standard drug with 38.50±0.36. The results of minimum inhibitory concentration showed that Shigella flexneri was the most susceptible with the MIC of 31.25 mg/ml and 62.5 mg/ml for both methanolic and aqueous extracts of P. daemia while salmonella typhi was the most susceptible with the MIC of 62.5 mg/ml and 125 mg/ml for M. charantia respectively. The presence of alkaloids, saponins, tannins and terpenoids showed that the plants leaves have antibacterial activity. The results of this study support the use of these plants as therapeutic agents for diarrhoea caused by S. flexneri and E. coli.

Dust sprinkling as an effective method for infecting layer chickens with wild-type Salmonella Typhimurium and changes in host gut microbiota.

Role of dust in Salmonella transmission on chicken farms is not well characterised. Salmonella Typhimurium (ST) infection of commercial layer chickens was investigated using a novel sprinkling method of chicken dust spiked with ST and the uptake compared to a conventional oral infection. While both inoculation methods resulted in colonisation of the intestines, the Salmonella load in liver samples was significantly higher at 7 dpi after exposing chicks to sprinkled dust compared to the oral infection group. Infection of chickens using the sprinkling method at a range of doses showed a threshold for colonisation of the gut and organs as low as 1000 CFU/g of dust. Caecal content microbiota analysis post-challenge showed that the profiles of chickens infected by the sprinkling and oral routes were not significantly different; however, both challenges induced differences when compared to the uninfected negative controls. Overall, the study showed that dust sprinkling was an effective way to experimentally colonise chickens with Salmonella and alter the gut microbiota than oral gavage at levels as low as 1000 CFU/g dust. This infection model mimics the field scenario of Salmonella infection in poultry sheds. The model can be used for future challenge studies for effective Salmonella control.

Versatile Platinum Nanoparticles-Decorated Phage Nanozyme Integrating Recognition, Bacteriolysis, and Catalysis Capabilities for On-Site Detection of Foodborne Pathogenic Strains Vitality Based on Bioluminescence/Pressure Dual-Mode Bioassay.

Sensitive and on-site discrimination of live and dead foodborne pathogenic strains remains a significant challenge due to the lack of appropriate assay and signal probes. In this work, a versatile platinum nanoparticle-decorated phage nanozyme (P2@PtNPs) that integrated recognition, bacteriolysis, and catalysis was designed to establish the bioluminescence/pressure dual-mode bioassay for on-site determination of the vitality of foodborne pathogenic strains. Benefiting from the bacterial strain-level specificity of phage, the target Salmonella typhimurium (S.T) was specially captured to form sandwich complexes with P2@PtNPs on another phage-modified glass microbead (GM@P1). As the other part of the P2@PtNPs nanozyme, the introduced PtNPs could not only catalyze the decomposition of hydrogen peroxide to generate a significant oxygen pressure signal but also produce hydroxyl radicals around the target bacteria to enhance the bacteriolysis of phage and adenosine triphosphate release. It significantly improved the bioluminescence signal. The two signals corresponded to the total and live target bacteria counts, so the dead target could be easily calculated from the difference between the total and live target bacteria counts. Meanwhile, the vitality of S.T was realized according to the ratio of live and total S.T. Under optimal conditions, the application range of this proposed bioassay for bacterial vitality was 102-107 CFU/mL, with a limit of detections for total and live S.T of 30 CFU/mL and 40 CFU/mL, respectively. This work provides an innovative and versatile nanozyme signal probe for the on-site determination of bacterial vitality for food safety.

PSVI-7 A traceable signature for a recovery microbiome composition after a dysbiosis caused by a sanitary challenge in pigs

Abstract Recent insights continue to point to a causal role of the gastrointestinal (GI) microbiome in digestion, nutrient absorption, and host metabolism. The GI microbiome may be a frequent target of perturbation since some challenges (i.e., high density, temperature and air quality fluctuations, presence of endemic enteric pathogens) faced by pigs may altogether create a spectrum of contrasting sanitary conditions. Therefore, our study investigated the influence of increased dietary tryptophan, threonine, and methionine supplementation in pigs from “good” vs. “poor” sanitary conditions, on the GI microbiome over time. For that purpose, female growing pigs were randomly assigned in a 2 × 2 factorial design (n = 30/treatment), consisting of two sanitary conditions (“good” vs. “poor”) and two diets [control (CN) vs. supplemented with specific amino acids (Trp, Thr, and Met+Cys:Lys ratios increased to 20% greater than CN]. Pigs allocated to the “good” sanitary condition treatment were sham-inoculated with pure BHI broth and the barn was cleaned twice a day and disinfected once a week. Whereas, “poor” sanitary condition comprised of all pigs being inoculated with 2 x 109 CFU of Salmonella Typhimurium (ST), in addition to spreading fecal material from a commercial farm under sanitary challenge, followed by leaving the barn uncleaned throughout the study (poor + ST). Fecal samples (n = 11) were collected at day post-challenge (DPC) 0, 10, and 21, and were sequenced for 16S rRNA data analysis of community diversity (alpha and beta) and taxonomic changes over time. Our results demonstrated that both alpha (Shannon and Simpson) and beta diversity metrics were significantly altered at DPC 21 by differentiating “good” vs “poor + ST” treatments, despite amino acids supplementation in the diet. Bacterial taxonomic analysis further captured community level alterations by a marked dysbiosis occurring on pigs allocated under “poor + ST” sanitary conditions. “ST + poor” sanitary conditions altered community structure as measured by co-occurrence networks, which was particularly pointed out at DPI 21. Specifically, Clostridium sensu stricto 1, Intestinibacter, Rombustsia, Terrisporobacter, and Megasphaera were five taxa between others co-enriched in fecal samples from pigs allocated under “poor + ST” sanitary conditions at DPC 21. These putative SCFA-producing bacteria were positively straighter correlated between them (Figure 1), which suggests a traceable signature for a recovery microbiome composition after a dysbiosis. In conclusion, temporal changes in fecal swine microbiome of growing pigs may be reflective of sanitary status despite dietary supplementation of specific amino acids.

Bacitracin Methylene Disalicylate (BMD) Treatment Affects Spleen Proteome in Broiler Chicks Infected with Salmonella enteritidis.

Bacitracin Methylene Disalicylate (BMD), as a feed additive to poultry diets, enhances digestion, prevents Salmonella enteritidis (SE) colonization, and treats current infections. The objective of this study was to utilize a quantitative proteomic approach to determine the effect of BMD feed additive on broiler chickens challenged with SE in the spleen proteome. At 1 d of age, chicks were randomly allocated into four groups: control with and without SE challenge (CON, n = 60; CON-SE, n = 60), BMD with and without SE challenge (BMD, n = 60; BMD-SE, n = 60). Birds in the CON-SE and BMD-SE treatment were administered SE inoculum by oral gavage. On day three and day seven post-gavage, the spleen was collected aseptically from birds in each treatment group (CON, n = 4/day; CON-SE, n = 4/day; BMD, n = 4/day; BMD-SE, n = 4/day). Proteomic analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed an increased abundance of 115 proteins and decreased of 77 due to the BMD. Proteins that decreased in abundance were enriched for fibrinogen complex and extracellular space, whereas proteins that increased in abundance were enriched for proteasome-mediated ubiquitin-dependent protein catabolic process and mitochondrion. Analysis of the interaction between BMD and the Salmonella challenge found 230 differentially abundant proteins including proteins associated with RNA binding, spliceosome, protein transport, and cell adhesion among the upregulated proteins, and those associated with protein folding, carbon metabolism, biosynthesis of nucleotide sugars, response to oxidative stress, positive regulation of NIK/NF-kappaB signaling, and inflammatory response among the downregulated proteins. The impact of BMD treatment on spleen proteome indicates an anti-apoptotic effect. BMD also modified the response of the spleen to the SE challenge with a marked decrease in proteins that prompt cytokine synthesis and an increase in proteins involved in the selective removal of unfolded proteins.

Prevalence of salmonella infection among the suspected enteric fever patients conducted at secondary hospital, Kathmandu, Nepal

Prevalence of salmonella infection among the suspected enteric fever patients conducted at secondary hospital, Kathmandu, Nepal

STM1863, a Member of the DUFs Protein Family, Is Involved in Environmental Adaptation, Biofilm Formation, and Virulence in Salmonella Typhimurium.

Salmonella Typhimurium (STM) is an important zoonotic Gram-negative pathogen that can cause infection in a variety of livestock and poultry. Meanwhile, as an important foodborne pathogen, the bacterium can survive in various stressful environments and transmits through the fecal-oral route, posing a serious threat to global food safety. To investigate the roles of STM1863, a member of the DUFs protein family, involved in STM environmental adaptation, biofilm formation, and virulence. We analyzed the molecular characteristics of the protein encoded by STM1863 gene and examined intra- and extracellular expression levels of STM1863 gene in mouse macrophages. Furthermore, we constructed STM1863 gene deletion and complementation strains and determined its environmental adaptation under stressful conditions such as acid, alkali, high salt, bile salt, and oxidation. And the capacity of biofilm formation and pathogenicity of those strains were analyzed and compared. In addition, the interaction between the promoter of STM1863 gene and RcsB protein was analyzed using DNA gel electrophoresis migration assay (electrophoretic mobility shift assay [EMSA]). The experiments revealed that acid adaptability and biofilm formation ability of STM1863 gene deletion strain were significantly weakened compared with the parental and complementary strains. Moreover, the adhesion and invasion ability of STM1863 deletion strain to mouse macrophages was significantly decreased, while the median lethal dose (LD50) increased by 2.148-fold compared with the parental strain. In addition, EMSA confirmed that RcsB protein could bind to the promoter sequence of STM1863 gene, suggesting that the expression of STM1863 gene might be modulated by RcsB. The present study demonstrated for the first time that STM1863, a member of the DUFs protein family, is involved in the modulation of environmental adaptation, biofilm formation, and virulence.

Enhancing pathogen identification in cheese with high background microflora using an artificial neural network-enabled paper chromogenic array sensor approach

Biohazards, which may occur at all supply chain stages, pose significant threats to food safety and public health. Addressing these concerns and enhancing food safety necessitates a nondestructive pathogen surveillance approach capable of continuously and simultaneously detecting multiple pathogens. Detecting and differentiating low concentrations of pathogenic bacteria amid high background microflora levels in foods is challenging, requiring technology with high sensitivity and robust discriminatory capability. This study introduces an artificial neural network-driven paper chromogenic array sensor (ANN-PCA) technique developed for the nondestructive, continuous, and simultaneous detection of Salmonella Enteritidis (SE) and Escherichia coli O157:H7 (Ec) from a high background microflora in shredded cheddar cheese. This method enables accurate detection of SE and Ec in monoculture and cocktail culture while distinguishing them from a high level of background microflora (∼7.5 log CFU/g), with accuracies ranging from 72 ± 11% to 92 ± 3%. In addition, SE and Ec were successfully identified at concentrations as low as 1 log CFU/g within one day, with an accuracy of 72 ± 11%. This approach exhibits promising potential for integration into a digitalized, smart, and resilient nondestructive surveillance system for real-time pathogen detection in foods throughout the supply chain without enrichment, incubation, or other sample preparation steps.