Enteritidis Infection Research Articles

Preclinical evaluation of OMVs as potential vaccine candidates against Salmonella enterica serovar Enteritidis infection.

Salmonella enterica serovar Enteritidis is the most prevalent serotype that causes human infections worldwide. Consumption of S. Enteritidis-contaminated animal foods is a major source of human infections; however, eradicating bacteria from animals remains difficult. Therefore, it is necessary to develop new measures to prevent and control salmonellosis. Here, we used the outer-membrane vesicles (OMVs) of S. Enteritidis and assessed their protective efficacy and immune response in mice. Deletion of tolR in S. Enteritidis increased the production and size of OMVs compared to those in the wild type (WT) and ΔrfaQ strains. Intramuscular immunization with OMVs conferred greater protection than intraperitoneal and intranasal immunization. Moreover, OMVs extracted from both WT and ΔtolR strains provided an 83.3% protective rate in mice challenged with S. Enteritidis, which was higher than that provided by OMVs extracted from the ΔrfaQ strain. However, compared with OMVs from the ΔtolR strain, OMVs from WT and ΔrfaQ strains rapidly eradicated S. Enteritidis colonizing the liver, spleen, ileum, and cecum of BALB/c mice after immunization. Immunization with OMVs from each of the three strains induced humoral immune responses and showed no side effects on the growth of mice. Our study revealed that OMVs from various S. Enteritidis strains could be developed for use as subunit vaccine candidates against nontyphoidal Salmonella infections in mammals.

Effect of Lactobacillus reuteri S5 Intervention on Intestinal Microbiota Composition of Chickens Challenged with Salmonella enteritidis.

Simple SummaryThe interaction between intestinal microbiota and host plays a key role in the development of intestinal diseases. Salmonella enteritidis infection is a common cause of human gastroenteritis, which can lead to gastrointestinal dysfunction and microecological disorder. It is an important public health problem all over the world. Lactic acid bacteria are among the main probiotics in the intestinal microbiota, which is one of the main defense lines against intestinal pathogens. It is now also considered to be an effective alternative antibiotic to fight pathogenic bacterial infections. In order to explore the potential mechanism of lactic acid bacteria against S. enteritidis infection, this study started from the perspective of lactic acid bacteria regulating the intestinal microbiota and the infection of antigenic bacteria. The probiotic strain Lactobacillus reuteri S5 (L. reuteri S5) was used to establish an animal model of S. enteritidis infection in broilers. The regulatory effect of L. reuteri S5 on the intestinal microbiota structure of chickens infected with S. enteritidis is studied by high throughput sequencing technology. The results showed that L. reuteri S5 could regulate the composition and abundance of intestinal microbiota and resist the infection of S. enteritidis.To understand the mechanism of lactic acid bacteria against Salmonella enteritidis infection; we examined how lactic acid bacteria regulated the intestinal microbiota to resist infection by pathogenic bacteria. The probiotic strain Lactobacillus reuteri S5 was used to construct an animal model of S. enteritidis infected broilers. A high-throughput sequencing technology was used to analyze the regulatory effects of L. reuteri S5 on the structure of the intestinal microbiota of broilers infected with S. enteritidis; and to examine the possible defense mechanism they used. Our results showed that the administration of L. reuteri S5 reduced colonization of S. enteritidis (p < 0.05), decreased intestinal permeability (p < 0.05), and reduced the bacterial displacement likely due by S. enteritidis colonization (p < 0.05), suggesting some enhancement of the intestinal barrier function. Furthermore, L. reuteri S5 increased the number of operational taxonomic units (OTUs) in the chicken cecal microflora and the relative abundance of Lactobacillaceae and decreased the relative abundance of Enterobacteriaceae. These results suggest that the lactic acid bacterium L. reuteri S5 protected the intestinal microbiota of chickens against S. enteritidis infection.

Dietary selenium sources alleviate immune challenge induced by Salmonella Enteritidis potentially through improving the host immune response and gut microbiota in laying hens.

The aim of this study was to evaluate the effects of different selenium (Se) sources on the immune responses and gut microbiota of laying hens challenged with Salmonella enteritidis (S. Enteritidis). A total of 240 45-week-old layers were randomly divided into eight groups with six replicates per group according to a 4 × 2 factorial design, including a blank diet without Se supplementation (CON group) and three diets with 0.3 mg/kg Se supplementation from sodium selenite (IS group), yeast Se (YS group), and selenium-enriched yeast culture (SYC group), respectively. After 8 weeks of feeding, half of them were orally challenged with 1.0 ml suspension of 109 colony-forming units per milliliter of S. Enteritidis daily for 3 days. The serum was collected on days 3, 7, and 14, and the cecum content was collected on day 14 after challenge. There was no significant difference in laying performance among the eight groups before challenge. The S. Enteritidis challenge significantly decreased the laying performance, egg quality, GSH-Px, IgG, and IgM and increased the ratio of feed and egg, malondialdehyde (MDA), Salmonella-specific antibody (SA) titers, IL-6, IL-2, IL-1β, and INF-γ. However, SYC increased the level of GSH-Px and IgG and decreased IL-6, while YS decreased the level of IL-2 and IL-1β. What is more, Se supplementation decreased the SA titers to varying degrees and reduced the inflammatory cell infiltration in the lamina propria caused by S. Enteritidis infection. In addition, the S. Enteritidis challenge disrupted the intestinal flora balance by reducing the abundance of the genera Clostridium innocuum, Lachnospiraceae, and Bifidobacterium and increasing the genera Butyricimonas and Brachyspira, while Se supplementation increased the gut microbial alpha diversity whether challenged or not. Under the S. Enteritidis challenge condition, the alteration of microbial composition by the administration of different Se sources mainly manifested as IS increased the relative abundance of the genera Lachnospiraceae and Christensenellaceae, YS increased the relative abundance of the genera Megamonas and Sphingomonas, and SYC increased the genera Fusobacterium and Lactococcus. The alteration of gut microbial composition had a close relationship with antioxidant or immune response. To summarize, different Se sources can improve the egg quality of layers challenged by S. Enteritidis that involves elevating the immunity level and regulating the intestinal microbiota.

Research Note: Internal organ colonization by Salmonella Enteritidis in experimentally infected layer pullets reared at different stocking densities in indoor cage-free housing

Contamination of eggs by Salmonella has often been identified as a source of food-borne human illness. S. Enteritidis is deposited inside developing eggs when invasive infections of laying hens reach the reproductive organs. The susceptibility of hens in cage-based housing systems to S. Enteritidis has been associated with their stocking density, but the applicability of this information to extensive (cage-free) systems is uncertain. The present study assessed internal organ colonization by S. Enteritidis in egg-type pullets reared at 2 different stocking densities in cage-free housing. Pullets were reared at either 374 cm2 or 929 cm2 of floor space per bird. At 16 wk of age, 4 groups of 72 pullets were moved into isolation rooms simulating commercial cage-free barns; 1/3 of the pullets in 2 rooms were orally inoculated with S. Enteritidis immediately after transfer and pullets in 2 rooms were similarly infected at 19 wk. At 6 and 12 d postinoculation, the pullets were euthanized and samples of liver, spleen, and intestinal tract were removed for bacteriologic culturing. No significant differences (P > 0.05) in S. Enteritidis isolation frequencies from any tissue were observed between high and low density rearing groups following infection at either age. However, S. Enteritidis was found significantly (P < 0.05) more frequently among pullets infected orally at 19 wk than at 16 wk in spleens and intestines. Likewise, the frequency of S. Enteritidis isolation from all birds (inoculated plus contact-exposed) at 19 wk was significantly higher than at 16 wk in livers and spleens. This increased susceptibility to invasive S. Enteritidis infection at reproductive maturity emphasizes the importance of risk reduction at a critical stage in the egg production cycle.

Effects of Clostridium butyricum on intestinal environment and gut microbiome under Salmonella infection

Salmonellosis causes massive economic losses globally every year. Especially in poultry, numerous drug-resistant bacteria have emerged; thus, it is imperative to find alternatives to antibiotics. As a probiotic, Clostridium butyricum (C. butyricum) provides the latest strategy for inhibiting the proliferation of Salmonella. This study aimed to evaluate the effects of C. butyricum on intestinal environment and gut microbiome under Salmonella infection. In this study, we modeled the infection of Salmonella using specific pathogen-free (SPF) chicks and found that the use of C. butyricum directly reduced the number of Salmonella colonizations in the spleen and liver. It also alleviated the histopathological changes of the liver, spleen, and cecum caused by Salmonella Enteritidis (S. Enteritidis). In addition, S. Enteritidis increased the expression of pro-inflammatory IL-6 in the cecum on day 6 postinfection. Interestingly, we found that C. butyricum changed PPAR-γ transcript levels in the cecum on day 6 postinfection. Analysis of the chick gastrointestinal microbiome showed that Salmonella infection increased the relative abundance of Subdoligranulum variabile. Further analysis found that Salmonella challenge significantly reduced the relative abundance of Faecalibacterium prausnitzii and C. butyricum increased the relative abundance of anaerobic bacteria in the gut on day 6 postinfection. Moreover, early supplementation of C. butyricum restored the epithelial hypoxia in S. Enteritidis infection in chicks. The results suggest that C. butyricum restores epithelial hypoxia caused by S. Enteritidis, improves the stability of intestinal flora, and inhibits the proliferation of Salmonella.

The Efficacy of a Trivalent Inactivated Salmonella Vaccine Combined with the Live S. Gallinarum 9R Vaccine in Young Layers after Experimental Infections with S. Enteritidis, S. Typhimurium, and S. Infantis.

Worldwide, poultry infections by Salmonella are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering the efforts and control measures that must be constantly applied, especially due to zoonotic serovars. Poultry is a common reservoir of Salmonella and its transmission into the food chain is a risk for humans. The vaccination of layers plays an important role in the overall efforts to prevent Salmonella infections. An inactivated trivalent vaccine was prepared with S. Enteritidis, S. Typhimurium, and S. Infantis strains. Infection trials were performed to evaluate the efficacy of three vaccination schedules using inactivated and live S. Gallinarum 9R vaccines. For this purpose, at week 5 of life, one subcutaneous dose of live S. Gallinarum 9R vaccine (1–5 × 107 CFU) was given to Groups 1 and 2. At weeks 8 and 11 of life, chickens were also vaccinated with one (Group 1) or two (Groups 2 and 3) intramuscular doses of the inactivated oil-adjuvant trivalent vaccine (1 × 108 CFU/dose of each antigen). Group 4 consisted of chickens that remained unvaccinated (control). At week 14 of life, the efficacy of the vaccination plans was evaluated in three separate inoculation trials with S. Enteritidis, S. Typhimurium, or S. Infantis. After vaccination with the inactivated vaccine, homologous antibody production was observed, and after challenge, a significant reduction in the faecal shedding, invasion, and colonization of S. Typhimurium and S. Infantis was achieved by all vaccination schedules, while the vaccination with at least one dose of the live S. Gallinarum 9R vaccine was necessary to obtain such a significant protection against S. Enteritidis infection.

Effect of red ginger powder (Zingiber officinale var. rubrum) as a feed additive for starter and finisher broiler chicken to increase immunoglobulin A and immunoglobulin Y expression and to prevent intestinal injury due to Salmonella enteritidis infection

Background and Aim:Salmonellosis is an infectious disease that often occurs in chickens and is caused by Salmonella enteritidis. The use of antibiotics to prevent this disease can result in the development of resistance in pathogenic bacteria, in addition to the presence of antibiotic residues in consumed carcasses. Red ginger (Zingiber officinale var. rubrum) has active compounds that potentially act as immunomodulators which increase specific and non-specific immune responses through the induction of cytokine production. This study was conducted to determine the effects of red ginger powder mixed in feed for starter and finisher broiler chickens, based on the evaluation of the expression of immunoglobulin A (IgA), histopathologic description of the ileum and cecum, IgA, and immunoglobulin Y (IgY) expression in the spleen, and the isolation count of S. enteritidis in fresh fecal samples.Materials and Methods:A total of 100 starter and 100 finisher Cobb broiler chickens were divided into four groups, designated as T0, T1, T2, and T3, respectively: Group T0 was fed commercial feed with no added 2% red ginger powder or S. enteritidis induction, and served as a negative control; Group T1 was inoculated with a 0.25 mL S. enteritidis oral induction (1 × 107 colony-forming unit [CFU] [0.5 McFarland standard]), and served as a positive control; Group T2 was fed with feed containing 2% red ginger powder; while Group T3 was fed with feed containing 2% red ginger powder and was orally inoculated with S. enteritidis with a dose similar to T1. The normal feed was given on the 1st–7th days. The mixture of 2% red ginger powder was given on the 7th–15th days. The S. enteritidis was induced on the 15th day (1 × 107 CFU). Necropsy was performed on the 16th day and tissues were fixed in 10% formalin and routinely processed for histopathologic and immunohistochemical analyses. The data were analyzed using a one-way analysis of variance test, Tukey’s analysis, and the Mann–Whitney U non-parametric statistical analysis test.Results:The 2% red ginger powder was found to significantly (p < 0.05) increase IgA expression and additionally decrease tissue damage in the cecum and ileum. It also increased IgA and IgY expression in the spleen. In addition, a decrease was observed in the S. enteritidis number isolated from finisher fresh feces, but none was found in the isolated starter fresh feces.Conclusion:These findings indicate that the addition of red ginger powder to chicken feed is a potential natural immunomodulator against S. enteritidis infection.

Research Note: IsomiRs of chicken miR-146b-5p are activated upon Salmonella enterica serovar Enteritidis infection

In order to enrich the knowledge of chicken transcriptomic response to Salmonella enterica serovar Enteritidis infection, 2-day-old chicks were orally inoculated with this bacteria (1.0 × 108 cfu/mL), and then the cecum tissues of 3 days post-inoculation were utilized for RNA sequencing (6 replicates each for treatment group and control group). After analysis, we found a variety of inflammatory genes were triggered at the mRNA level upon infection. Notably, the expression profiles at the miRNA level and the isomiR level were heterogeneous. Certain isomiRs of chicken miR-146b-5p were significantly increased by more than 2 times compared to control (Padj < 0.05). Combining the bioinformatics prediction, transcriptome data and RT-qPCR results, we deduced that the isomiRs of chicken miR-146b-5p might act to sustain the RIG-I-like receptor signaling and type I interferon induction by repressing USP3 transcript. Our findings provide a new perspective on the regulatory function of miR-146b-5p and facilitate the study of isomiRs.

Intestinal Mucosal Immunity-Mediated Modulation of the Gut Microbiome by Oral Delivery of Enterococcus faecium Against Salmonella Enteritidis Pathogenesis in a Laying Hen Model.

Enterococcus faecium (E. faecium) is a protective role that has crucial beneficial functions on intestinal homeostasis. This study aimed to investigate the effects of E. faecium on the laying performance, egg quality, host metabolism, intestinal mucosal immunity, and gut microbiota of laying hens under the Salmonella Enteritidis (S. Enteritidis) challenge. A total of 400 45-week-old laying hens were randomly divided into four treatments (CON, EF, SCON, and SEF groups) with five replicates for each group and 20 hens per replicate and fed with a basal diet or a basal diet supplemented with E. faecium (2.5 × 108 cfu/g feed). The experiment comprised two phases, consisting of the pre-salmonella challenged phase (from day 14 to day 21) and the post-salmonella challenged phase (from day 21 to day 42). At day 21 and day 22, the hens in SCON and SEF groups were orally challenged with 1.0 ml suspension of 109 cfu/ml S. Enteritidis (CVCC3377) daily, whereas the hens in CON and EF groups received the same volume of sterile PBS. Herein, our results showed that E. faecium administration significantly improved egg production and shell thickness during salmonella infection. Also, E. faecium affected host lipid metabolism parameters via downregulating the concentration of serum triglycerides, inhibited oxidative stress, and enhanced immune functions by downregulating the level of serum malondialdehyde and upregulating the level of serum immunoglobulin G. Of note, E. faecium supplementation dramatically alleviated intestinal villi structure injury and crypt atrophy, and improved intestinal mucosal barrier injuries caused by S. Enteritidis challenge. Moreover, our data revealed that E. faecium supplementation ameliorated S. Enteritidis infection-induced gut microbial dysbiosis by altering the gut microbial composition (reducing Bacteroides, Desulfovibrio, Synergistes, and Sutterella, and increasing Barnesiella, Butyricimonas, Bilophila, and Candidatus_Soleaferrea), and modulating the gut microbial function, such as cysteine and methionine metabolism, pyruvate metabolism, fatty acid metabolism, tryptophan metabolism, salmonella infection, and the PI3K-Akt signaling pathway. Taken together, E. faecium has a strong capacity to inhibit the S. Enteritidis colonization of hens. The results highlight the potential of E. faecium supplementation as a dietary supplement to combat S. Enteritidis infection in animal production and to promote food safety.

Effectiveness of Administering a Mixture of Lactic Acid Bacteria to Control Salmonella ser. Enteritidis Infections in Broilers.

Simple SummarySalmonella infection is one of the main causes of food poisoning through poultry consumption. Among the various methods used to control this infection, the use of lactic acid bacteria is economical, with little risk of developing antibiotic-resistant bacteria. We selected three Lactobacillus spp. capable of inhibiting Salmonella proliferation in vitro and administered their mixture to 1-day-old chicks to investigate their effect. We suggest that the Lactobacillus mixture formulated in this study aids in protecting poultry farms from Salmonella contamination, further securing food safety.Non-typhoidal Salmonella spp. cause persistent asymptomatic infections in poultry. The consumption of Salmonella-infected poultry products is associated with food poisoning. One of the pathogens that causes such infections is Salmonella ser. Enteritidis (SE). Therefore, alternative measures are required for better control of salmonellosis and to reduce potential antibiotic use. Here, the efficacy of a mixture of lactic acid bacteria (LAB), formulated based on competitive exclusion, was evaluated. The LAB mixture was administered to 1- to 20-day-old chickens using different schemes; the chickens were then inoculated with an SE strain, which was previously identified to be prevalent in broiler breeder farms. Even with short-term administration, the group treated with LAB exhibited lower SE isolation levels in the spleen and cecal content and greater weight gain than that in the control group. This protective efficacy of LAB was retained even after two weeks without LAB administration. According to the results of animal experiments and field tests, evidence of SE infection was absent after treatment of the animals with the LAB formulation used in this study. Thus, this LAB mixture can be used as a potential strategy for protecting poultry farms from Salmonella contamination. This will also help reduce potential antibiotic use.

Bacillus coagulans protect against Salmonella enteritidis-induced intestinal mucosal damage in young chickens by inducing the differentiation of goblet cells

Bacillus coagulans (B. coagulans) have proven to be effective in improving the development of gut immunity and microbiome, and offering protection against pathogens, especially in young animals. The newborn chicks are highly vulnerable to the foodborne pathogenic Salmonella infections, leading to high mortality and economic loss. However, whether B. coagulans can protect young chickens from Salmonella-induced intestinal mucosal damage by modulating the development of intestinal epithelium remains unclear. In this study, B. coagulans with excellent anti-Salmonella property was selected and used. The results showed that B. coagulans alleviated the morphological damage, intestinal inflammation and body weight loss caused by Salmonella enteritidis (S. enteritidis) infections. B. coagulans significantly increased the crypt depth. Furthermore, the goblet cell loss and downregulating of mucin 2 induced by S. enteritidis were all relieved by B. coagulans treatment. Consistently, the expression of the related genes of Notch signaling pathway was also upregulated in the S. enteritidis group but inhibited by B. coagulans. In addition, B. coagulans improved the levels of immunoglobulin A, superoxide dismutase, total antioxidant capacity, and avian beta-defensin 2 in the intestinal mucosa. This study demonstrated that B. coagulans could regulate the development of intestinal epithelium, protect the intestinal barrier, thus relieve infections with S. enteritidis in chicks, which can be used as alternatives to antibiotics in poultry feed.

Infection Heterogeneity and Microbiota Differences in Chicks Infected by Salmonella enteritidis.

This study was conducted to compare the infection heterogeneity and cecal microbiota in chicks infected by S. enteritidis. Forty-eight 8-d-old female Arbor Acres chicks were challenged with S. enteritidis and euthanized 24 h later. The eight chicks with the highest Salmonella tissue loads were assigned to group S (S. enteritidis-susceptible), and the eight chicks with the lowest Salmonella tissue loads were assigned to group R (S. enteritidis-resistant). Chicks in group S showed a higher liver index (p < 0.05), obvious liver lesions, and an decreasing trend for the villus height-to-crypt depth ratio (p < 0.10), compared with those in group R. Gene expression of occludin, MUC2, and IL10 was higher, whereas that of iNOS and IL6 was lower (p < 0.05), in chicks of group R relative to those in group S. Separation of the cecal microbial community structure has been found between the two groups. The S. enteritidis-susceptible chicks showed higher abundance of pathogenic bacteria (Fusobacterium and Helicobacter) in their cecal, while Desulfovibrio_piger was enriched in the cecal of S. enteritidis-resistant chicks. In summary, chicks showed heterogeneous responses to S. enteritidis infection. Enhanced intestinal barrier function and cecal microbiota structure, especially a higher abundance of Desulfovibrio_piger, may help chicks resist S. enteritidis invasion.

Characterization of Salmonella serotypes prevalent in asymptomatic people and patients

BackgroundInfection with Salmonella enterica usually results in diarrhea, fever, and abdominal cramps, but some people become asymptomatic or chronic carrier as a source of infection for others. This study aimed to analyze the difference in serotype, antimicrobial resistance, and genetic profiles between Salmonella strains isolated from patients and those from asymptomatic people in Nantong city, China.MethodsA total of 88 Salmonella strains were collected from patients and asymptomatic people from 2017 to 2018. Serotyping, antimicrobial susceptibility testing, and PFGE analysis were performed to analyze the characteristics of these strains.ResultsTwenty serotypes belonging to 8 serogroups were identified in the 88 Salmonella strains. S. Typhimurium remained to be the predominant serotype in strains from both patients and asymptomatic people. Among the 27 strains from patients, S. Enteritidis and S. Rissen were shown as the other two major serotypes, while S. London, S. Derby, and S. Meleagridis were demonstrated as the other significant serotypes among the 61 strains from asymptomatic people. Antimicrobial resistance testing revealed that 84.1% of strains from both resources were multi-drug resistant. PFGE displayed a highly discriminative ability to differentiate strains belonging to S. Derby, S. Typhimurium, etc., but could not efficiently differentiate serotypes like S. Enteritidis.ConclusionsThis study’s results demonstrated that S. Typhimurium could cause human infection in both symptomatic and asymptomatic state; S. London, S. Derby, and S. Meleagridis usually cause asymptomatic infection, while S. Enteritidis infection mainly results in human diseases. The high multi-drug resistance rate detected in the antimicrobial resistance and diverse PFGE profiles of these strains implied that the strains were isolated from different sources, and the increased surveillance of Salmonella from both patients and asymptomatic people should be taken to control the disease.

Identification of Differentially Expressed Non-coding RNA Networks With Potential Immunoregulatory Roles During Salmonella Enteritidis Infection in Ducks.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a pathogen that can colonize the preovulatory follicles of poultry, thereby causing both reduced egg production and an elevated risk of foodborne salmonellosis in humans. Although a few studies have revealed S. Enteritidis preferentially invades the granulosa cell layer within these follicles, it can readily persist and proliferate through mechanisms that are not well-understood. In this study, we characterized competing endogenous RNA (ceRNA) regulatory networks within duck granulosa cells following time-course of S. Enteritidis challenge. The 8108 long non-coding RNAs (lncRNAs), 1545 circular RNAs (circRNAs), 542 microRNAs (miRNAs), and 4137 mRNAs (fold change ≥2; P < 0.01) were differentially expressed during S. Enteritidis challenge. Also, eight mRNAs, eight lncRNAs and five circRNAs were selected and the consistent expression trend was found between qRT-PCR detection and RNA-seq. Moreover, the target genes of these differentially expressed ncRNAs (including lncRNAs, circRNAs and miRNAs) were predicted, and significantly enriched in the innate immune response and steroidogenesis pathways. Then, the colocalization and coexpression analyses were conducted to investigate relationships between ncRNAs and mRNAs. The 16 differentially expressed miRNAs targeting 60 differentially expressed mRNAs were identified in granulosa cells at 3 and 6 h post-infection (hpi) and enriched in the MAPK, GnRH, cytokine-cytokine receptor interaction, Toll-like receptor, endocytosis, and oxidative phosphorylation signaling pathways. Additionally, underlying lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA ceRNA networks were then constructed to further understand their interaction during S. Enteritidis infection. Lnc_012227 and novel_circ_0004892 were identified as ceRNAs, which could compete with miR-let-7g-5p and thereby indirectly modulating map3k8 expression to control S. Enteritidis infection. Together, our data thus identified promising candidate ncRNAs responsible for regulating S. Enteritidis infection in the preovulatory follicles of ducks, offering new insights regarding the ovarian transmission of this pathogen.

The modulatory effects of alfalfa polysaccharide on intestinal microbiota and systemic health of Salmonella serotype (ser.) Enteritidis-challenged broilers

Salmonella serotype (ser.) Enteritidis infection in broilers is a main foodborne illness that substantially threatens food security. This study aimed to examine the effects of a novel polysaccharide isolated from alfalfa (APS) on the intestinal microbiome and systemic health of S. ser. Enteritidis-infected broilers. The results indicated that broilers receiving the APS-supplemented diet had the improved (P < 0.05) growth performance and gut health than those fed no APS-supplemented diet. Supplementation with APS enhanced (P < 0.05) the richness of gut beneficial microbes such as Bacteroidetes, Barnesiella, Parabacteroides, Butyricimonas, and Prevotellaceae, while decreased (P < 0.05) the abundance of facultative anaerobic bacteria including Proteobacteria, Actinobacteria, Ruminococcaceae, Lachnospiraceae, and Burkholderiaceae in the S. ser. Enteritidis-infected broilers. The Bacteroides and Odoribacter were identified as the two core microbes across all treatments and combined with their syntrophic microbes formed the hub in co-occurrence networks linking microbiome structure to performance of broilers. Taken together, dietary APS supplementation improved the systemic health of broilers by reshaping the intestinal microbiome regardless of whether S. ser. Enteritidis infection was present. Therefore, APS can be employed as a potential functional additives to inhibit the S. ser. Enteritidis and enhance the food safety in poultry farming.

Sodium butyrate modulates chicken macrophage proteins essential for Salmonella Enteritidis invasion.

Salmonella Enteritidis is an intracellular foodborne pathogen that has developed multiple mechanisms to alter poultry intestinal physiology and infect the gut. Short chain fatty acid butyrate is derived from microbiota metabolic activities, and it maintains gut homeostasis. There is limited understanding on the interaction between S. Enteritidis infection, butyrate, and host intestinal response. To fill this knowledge gap, chicken macrophages (also known as HTC cells) were infected with S. Enteritidis, treated with sodium butyrate, and proteomic analysis was performed. A growth curve assay was conducted to determine sub-inhibitory concentration (SIC, concentration that do not affect bacterial growth compared to control) of sodium butyrate against S. Enteritidis. HTC cells were infected with S. Enteritidis in the presence and absence of SIC of sodium butyrate. The proteins were extracted and analyzed by tandem mass spectrometry. Our results showed that the SIC was 45 mM. Notably, S. Enteritidis-infected HTC cells upregulated macrophage proteins involved in ATP synthesis through oxidative phosphorylation such as ATP synthase subunit alpha (ATP5A1), ATP synthase subunit d, mitochondrial (ATP5PD) and cellular apoptosis such as Cytochrome-c (CYC). Furthermore, sodium butyrate influenced S. Enteritidis-infected HTC cells by reducing the expression of macrophage proteins mediating actin cytoskeletal rearrangements such as WD repeat-containing protein-1 (WDR1), Alpha actinin-1 (ACTN1), Vinculin (VCL) and Protein disulfide isomerase (P4HB) and intracellular S. Enteritidis growth and replication such as V-type proton ATPase catalytic subunit A (ATPV1A). Interestingly, sodium butyrate increased the expression of infected HTC cell protein involving in bacterial killing such as Vimentin (VIM). In conclusion, sodium butyrate modulates the expression of HTC cell proteins essential for S. Enteritidis invasion.

Protection Conferred by Drinking Water Administration of a Nanoparticle-Based Vaccine against Salmonella Enteritidis in Hens.

Salmonellosis remains a major medical and an unmet socioeconomic challenge. Worldwide, more than three million deaths per year are associated with Salmonella enterica serovar Enteritidis infections. Although commercially available vaccines for use in poultry exist, their efficacy is limited. We previously described a method for isolating a heat extract (HE) fraction of the cell surface of S. Enteritidis that contained major antigenic complexes immunogenic in hens naturally infected with the bacterium. One single dose of S. Enteritidis’ HE induced protection against lethal salmonellosis in mice. Furthermore, HE encapsulation in nanoparticles of the copolymer of methyl vinyl ether and maleic anhydride (PVM/MA), Gantrez AN, improved and prolonged the protection against the disease in mice. We formulated new preparations of Gantrez AN nanoparticles with HE S. Enteritidis and assessed their stability in drinking water and their efficacy in hens after experimental infection. The oral treatment of six-week-old hens with two doses of HE nanoparticles significantly reduced the Salmonella excretion in hens. Due to the effectiveness of the treatment in reducing bacterial excretion, we conclude that HE nanoencapsulation obtained from S. Enteritidis is a viable novel vaccination approach against salmonellosis in farms.

Multi‐country outbreak of Salmonella Enteritidis sequence type (ST)11 infections linked to poultry products in the EU/EEA and the United Kingdom

EFSA Supporting PublicationsVolume 18, Issue 3 6486E Joint ECDC-EFSA rapid outbreak assessmentOpen Access Multi-country outbreak of Salmonella Enteritidis sequence type (ST)11 infections linked to poultry products in the EU/EEA and the United Kingdom First published: 01 March 2021 https://doi.org/10.2903/sp.efsa.2021.EN-6486 Requestor: European Commission Question number: EFSA-Q-2020-00724 This article was originally published on the EFSA website www.efsa.europa.eu on 25 February 2021 as part of EFSA's urgent publication procedures AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Abstract Between May 2018 and December 2020, 193 human cases of Salmonella Enteritidis sequence type (ST)11 were reported in Denmark (2), Finland (4), France (33), Germany (6), Ireland (12), the Netherlands (3), Poland (5), Sweden (6), and the United Kingdom (UK) (122). One in five cases was hospitalised. One death was reported. Fifty percent of the cases were children ≤ 18 years. The most recent case was reported by the UK in December 2020. Epidemiological studies in the UK have identified an increased risk of S. Enteritidis infection associated with the consumption of frozen breaded chicken products. Five batches of non-ready-to-eat poultry products (e.g. breaded products) tested positive for S. Enteritidis matching the outbreak strain. Three of these were manufactured by the Polish Processing Company B where S. Enteritidis was not detected. The five positive batches were traced back to different meat suppliers, slaughterhouses, and/or farms in Poland. Some of these farms had positive results for S. Enteritidis in 2020 (no whole genome sequencing typing). The scarce typing information available for the primary production did not enable the identification of a microbiological link between the positive Polish farms and the contaminated products. Control measures were implemented for the products involved (e.g. withdrawals, recalls). The whole genome sequencing analysis of human and food S. Enteritidis isolates confirmed a cluster with 0-3 allelic differences through single linkage clustering. This, in combination with epidemiological and traceability data, suggests common source(s) in the food chain. There remains a risk of infection in connection with the consumption of implicated poultry products purchased before the withdrawals, if these products are not properly cooked. Unknown source(s) of contamination and the identification of other Salmonella serotypes and S. Enteritidis strains indicate that these poultry products pose a recurrent risk for Salmonella infections in the EU/EEA and the UK. Volume18, Issue3March 20216486E ReferencesRelatedInformation

A forecast model for prevention of foodborne outbreaks of non-typhoidal salmonellosis.

BackgroundThis work presents a forecast model for non-typhoidal salmonellosis outbreaks.MethodThis forecast model is based on fitted values of multivariate regression time series that consider diagnosis and estimation of different parameters, through a very flexible statistical treatment called generalized auto-regressive and moving average models (GSARIMA).ResultsThe forecast model was validated by analyzing the cases of Salmonella enterica serovar Enteritidis in Sydney Australia (2014–2016), the environmental conditions and the consumption of high-risk food as predictive variables.ConclusionsThe prediction of cases of Salmonella enterica serovar Enteritidis infections are included in a forecast model based on fitted values of time series modeled by GSARIMA, for an early alert of future outbreaks caused by this pathogen, and associated to high-risk food. In this context, the decision makers in the epidemiology field can led to preventive actions using the proposed model.

Immunization With Outer Membrane Vesicles Derived From Major Outer Membrane Protein-Deficient Salmonella Typhimurium Mutants for Cross Protection Against Salmonella Enteritidis and Avian Pathogenic Escherichia coli O78 Infection in Chickens.

Colibacillosis is an economically important infectious disease in poultry, caused by avian pathogenic Escherichia coli (APEC). Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne diseases in human circulated through poultry-derived products, including meat and chicken eggs. Vaccine control is the mainstream approach for combating these infections, but it is difficult to create a vaccine for the broad-spectrum protection of poultry due to multiple serotypes of these pathogens. Our previous studies have shown that outer membrane vesicles (OMVs) derived from S. enterica serovar Typhimurium mutants with a remodeled outer membrane could induce cross-protection against heteroserotypic Salmonella infection. Therefore, in this study, we further evaluated the potential of broad-spectrum vaccines based on major outer membrane protein (OMP)-deficient OMVs, including ΔompA, ΔompC, and ΔompD, and determined the protection effectiveness of these candidate vaccines in murine and chicken infection models. The results showed that ΔompA led to an increase in the production of OMVs. Notably, ΔompAΔompCΔompD OMVs showed significantly better cross-protection against S. enterica serovar Choleraesuis, S. Enteritidis, APEC O78, and Shigella flexneri 2a than did other omp-deficient OMVs, with the exception of ΔompA OMVs. Subsequently, we verified the results in the chicken model, in which ΔompAΔompCΔompD OMVs elicited significant cross-protection against S. Enteritidis and APEC O78 infections. These findings further confirmed the feasibility of improving the immunogenicity of OMVs by remodeling the outer membrane and provide a new perspective for the development of broad-spectrum vaccines based on OMVs.