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Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for the sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, the regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, i.e., substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes the utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection.ImportanceBacterial pathogens must adapt their gene expression profiles to cope with diverse environments encountered during infection. This coordinated process is carried out by the integration of cues that the pathogen senses to fine-tune gene expression in a spatiotemporal manner. Many studies have elucidated the regulatory mechanisms of how Salmonella sense metabolites in the gut to activate or repress its virulence program; however, our understanding of how Salmonella coordinates its gene expression to maximize the utilization of carbon and energy sources found in transitional nutrient niches is not well understood. In this study, we discovered how Salmonella integrates two infection-relevant cues, substrate availability and exogenous electron acceptors, to control L-tartrate metabolism. From our experiments, we propose a model for how L-tartrate metabolism is regulated in response to different metabolic cues in addition to characterizing two previously unknown transcriptional regulators. This study expands our understanding of how microbes combine metabolic cues to enhance fitness during infection.

In sub-Saharan Africa, multidrug-resistant non-typhoidal Salmonella serovars are a common cause of fatal bloodstream infection. Malnutrition is a predisposing factor, but the underlying mechanisms are unknown. Here we show that vitamin A deficiency, one of the most prevalent micronutrient deficits afflicting African children, increases susceptibility to disseminated non-typhoidal Salmonella disease in mice and impairs terminal neutrophil maturation. Immature neutrophils had reduced expression of Slc11a1, a gene that encodes a metal ion transporter generally thought to restrict pathogen growth in macrophages. Adoptive transfer of SLC11A1-proficient neutrophils, but not SLC11A1-deficient neutrophils, reduced systemic Salmonella burden in Slc11a1-/- mice or mice with vitamin A deficiency. Loss of terminal granulopoiesis regulator CCAAT/enhancer-binding protein ϵ (C/EBPϵ) also decreased neutrophil-mediated control of Salmonella, but not that mediated by peritoneal macrophages. Susceptibility to infection increased in Cebpe-/- Slc11a1+/+ mice compared with wild-type controls, in an Slc11a1-expression-dependent manner. These data suggest that SLC11A1 deficiency impairs Salmonella control in part by blunting neutrophil-mediated defence.

Baby chicks administered a fecal transplant from adult chickens are resistant to Salmonella colonization by competitive exclusion. A two-pronged approach was used to investigate the mechanism of this process. First, Salmonella response to an exclusive (Salmonella competitive exclusion product, Aviguard®) or permissive microbial community (chicken cecal contents from colonized birds containing 7.85 Log10Salmonella genomes/gram) was assessed ex vivo using a S. typhimurium reporter strain with fluorescent YFP and CFP gene fusions to rrn and hilA operon, respectively. Second, cecal transcriptome analysis was used to assess the cecal communities response to Salmonella in chickens with low (≤5.85 Log10 genomes/g) or high (≥6.00 Log10 genomes/g) Salmonella colonization. The ex vivo experiment revealed a reduction in Salmonella growth and hilA expression following co-culture with the exclusive community. The exclusive community also repressed Salmonellas SPI-1 virulence genes and LPS modification, while the anti-virulence/inflammatory gene avrA was upregulated. Salmonella transcriptome analysis revealed significant metabolic disparities in Salmonella grown with the two different communities. Propanediol utilization and vitamin B12 synthesis were central to Salmonella metabolism co-cultured with either community, and mutations in propanediol and vitamin B12 metabolism altered Salmonella growth in the exclusive community. There were significant differences in the cecal communitys stress response to Salmonella colonization. Cecal community transcripts indicated that antimicrobials were central to the type of stress response detected in the low Salmonella abundance community, suggesting antagonism involved in Salmonella exclusion. This study indicates complex community interactions that modulate Salmonella metabolism and pathogenic behavior and reduce growth through antagonism may be key to exclusion.

This study aimed to investigate AMR profiles of Aeromonas hydrophila, Salmonella spp., and Vibrio cholerae isolated from Nile tilapia (Oreochromis spp.) (n = 276) purchased from fresh markets and supermarkets in Bangkok, Thailand. A sample of tilapia was divided into three parts: fish intestine (n = 276), fish meat (n = 276), and liver and kidney (n = 276). The occurrence of A. hydrophila, Salmonella, and V. cholerae was 3.1%, 7.4%, and 8.5%, respectively. A high prevalence of these pathogenic bacteria was observed in fresh market tilapia compared to those from supermarkets (p < 0.05). The predominant Salmonella serovars were Paratyphi B (6.4%), followed by Escanaba (5.7%), and Saintpaul (5.7%). All isolates tested positive for the virulence genes of A. hydrophila (aero and hly), Salmonella (invA), and V. cholerae (hlyA). A. hydrophila (65.4%), Salmonella (31.2%), and V. cholerae (2.9%) showed multidrug resistant isolates. All A. hydrophila isolates (n = 26) exhibited resistant to ampicillin (100.0%) and florfenicol (100.0%), and often carried sul1 (53.8%) and tetA (50.0%). Salmonella isolates were primarily resistant to ampicillin (36.9%), with a high incidence of blaTEM (26.2%) and qnrS (25.5%). For V. cholerae isolates, resistance was observed against ampicillin (48.6%), and they commonly carried qnrS (24.3%) and tetA (22.9%). To identify mutations in the quinolone resistance determining regions (QRDRs), a single C248A point mutation of C248A (Ser-83-Tyr) in the gyrA region was identified in six out of seven isolates of Salmonella isolates. This study highlighted the presence of antimicrobial-resistant pathogenic bacteria in Nile tilapia at a selling point. It is important to rigorously implement strategies for AMR control and prevention.

The emergence of variants posing threats to human health and animal production characterizes the epidemiology of Salmonella (1) and also S. enterica serovar Infantis (antigenic formula 6,7:r:1,5). Over the past [...]

The standard laboratory methods used to detect Salmonella are time-consuming, leading to unavoidable delays, which can be costly (e.g., food checks at customs) or even dangerous when quick alarms are needed (e.g., for potential outbreaks). To address this problem, we propose a rapid two-step colorimetric immunoassay. In the first step, gold nanoparticles interact with the sample, while in the second step, an optimized amount of saline solution is added to induce cluster formation among the unbound nanoparticles, providing a color change that inversely correlates with the bacteria concentration. The nanoparticles were functionalized using a technique based on UV activation of the antibodies, resulting in oriented antibodies with antigen-binding regions in the proximity of the surface. While a color change can be observed with the naked eye at relatively higher bacterial concentrations, a more quantitative approach based on UV–visible spectrum measurements allowed us to achieve a limit of detection of 1 cfu/mL in chicken samples. The test can be completed in 15 min and performed on-site, paving the way for widespread applications of our biosensor in the field of food safety. [ABSTRACT FROM AUTHOR]

Controlled human infection model (CHIM) studies, which involve deliberate exposure of healthy human volunteers to an infectious agent, are recognised as important tools to advance vaccine development. These studies not only facilitate estimates of vaccine efficacy, but also offer an experimental approach to study disease pathogenesis and profile vaccine immunogenicity in a controlled environment, allowing correlation with clinical outcomes. Consequently, the data from CHIMs can be used to identify immunological correlates of protection (CoP), which can help accelerate vaccine development. In the case of invasive Salmonella infections, vaccination offers a potential instrument to prevent disease. Invasive Salmonella disease, caused by the enteric fever pathogens Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi A, B and C, and nontyphoidal Salmonella (iNTS), remains a significant cause of mortality and morbidity in low- and middle-income countries, resulting in over 200,000 deaths and the loss of 15 million DALYs annually. CHIM studies have contributed to the understanding of S. Typhi infection and provided invaluable insight into the development of vaccines and CoP following vaccination against S. Typhi. However, CoP are less well understood for S. Paratyphi A and iNTS. This brief review focuses on the contribution of vaccine-CHIM trials to our understanding of the immune mechanisms associated with protection following vaccines against invasive Salmonella pathogens, particularly in relation to CoP. [ABSTRACT FROM AUTHOR]

ABSTRACT DNA viruses recognize viral DNA and package it into virions. Specific recognition is needed to distinguish viral DNA from host cell DNA. The λ‐like Escherichia coli phages are interesting and good models to examine genome packaging by large DNA viruses. Gifsy‐1 is a λ‐like Salmonella phage. Gifsy‐1's DNA packaging specificity was compared with those of closely related phages λ, 21, and N15. In vivo packaging studies showed that a Gifsy‐1‐specific phage packaged λ DNA at ca. 50% efficiency and λ packages Gifsy‐1‐specific DNA at ~30% efficiency. The results indicate that Gifsy‐1 and λ share the same DNA packaging specificity. N15 is also shown to package Gifsy‐1 DNA. Phage 21 fails to package λ, N15, and Gifsy‐1‐specific DNAs; the efficiencies are 0.01%, 0.01%, and 1%, respectively. A known incompatibility between the 21 helix‐turn‐helix motif and cosBλ is proposed to account for the inability of 21 to package Gifsy‐1 DNA. A model is proposed to explain the 100‐fold difference in packaging efficiency between λ and Gifsy‐1‐specific DNAs by phage 21. Database sequences of enteric prophages indicate that phages with Gifsy‐1's DNA packaging determinants are confined to Salmonella species. Similarly, prophages with λ DNA packaging specificity are rarely found in Salmonella. It is proposed that λ and Gifsy‐1 have diverged from a common ancestor phage, and that the differences may reflect adaptation of their packaging systems to host cell differences. [ABSTRACT FROM AUTHOR]

ABSTRACT Bacterial cell division is orchestrated by proteins that assemble in dynamic complexes collectively known as the divisome. Essential monofunctional enzymes with glycosyltransferase or transpeptidase (TPase) activities, FtsW and FtsI respectively, engage in the synthesis of septal peptidoglycan (sPG). Enigmatically, Salmonella has two TPases that can promote cell division independently: FtsI (PBP3) and the pathogen‐specific paralogue PBP3SAL. How Salmonella regulates the assembly of the sPG synthase complex with these two TPases, is unknown. Here, we characterized Salmonella division complexes in wild‐type cells and isogenic mutants lacking PBP3 or PBP3SAL. The complexes were cross‐linked in vivo and pulled down with antibodies recognizing each enzyme. Proteomics of the immunoprecipitates showed that PBP3 and PBP3SAL do not extensively cross‐link in wild type cells, supporting the presence of independent complexes. More than 40 proteins cross‐link in complexes in which these two TPases are present. Those identified with high scores include FtsA, FtsK, FtsQLB, FtsW, PBP1B, SPOR domain‐containing proteins (FtsN, DedD, RlpA, DamX), amidase activators (FtsX, EnvC, NlpD) and Tol‐Pal proteins. Other cross‐linked proteins are the protease Prc, the elongasome TPase PBP2 and, D,D‐endo‐ and D,D‐carboxypeptidases. PBP3 and PBP3SAL localize at midcell and compete for occupying the division complex in response to environmental cues. Thus, a catalytic‐dead PBP3SAL‐S300A variant impairs cell division in a high osmolarity and acidic condition in which it is produced at levels exceeding those of PBP3. Salmonella may therefore exploit an ‘adjustable’ divisome to exchange TPases for ensuring cell division in distinct environments and, in this manner, expand its colonization capacities. [ABSTRACT FROM AUTHOR]

A novel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samples is presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs μm−2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5 CFU mL−1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Simple Summary: An extensive countrywide investigation was carried out in Greece to study gastrointestinal zoonotic pathogens in horses. Faecal samples were collected and tested. Gastrointestinal pathogens were detected in the faecal samples obtained from 43% of horses examined. They were detected more frequently in samples from horses in courtyard housing. The most frequently detected zoonotic pathogens were enteropathogenic Escherichia coli and Shiga-like toxin-producing E. coli stx1/stx2. The decreasing age of horses and the presence of livestock at the same premises as the horses emerged to be significantly associated with the detection of pathogens. The findings have indicated the presence of pathogens with zoonotic potential in horses and have suggested factors that may play some role in this. The objectives of this study were (a) to detect zoonotic gastrointestinal pathogens in faecal samples of horses using the FilmArray® GI Panel and (b) to identify variables potentially associated with their presence. Faecal samples collected from 224 horses obtained during a countrywide study in Greece were tested by means of the BioFire® FilmArray® Gastrointestinal (GI) Panel, which uses multiplex-PCR technology for the detection of 22 pathogens. Gastrointestinal pathogens were detected in the faecal samples obtained from 97 horses (43.3%). Zoonotic pathogens were detected more frequently in samples from horses in courtyard housing (56.0%) than in samples from horses in other housing types (39.7%) (p = 0.040). The most frequently detected zoonotic pathogens were enteropathogenic Escherichia coli (19.2% of horses) and Shiga-like toxin-producing E. coli stx1/stx2 (13.8%). During multivariable analysis, two variables emerged as significant predictors for the outcome 'detection of at least one zoonotic pathogen in the faecal sample from an animal': (a) the decreasing age of horses (p = 0.0001) and (b) the presence of livestock at the same premises as the horses (p = 0.013). As a significant predictor for the outcome 'detection of two zoonotic pathogens concurrently in the faecal sample from an animal', only the season of sampling of animals (autumn) emerged as significant in the multivariable analysis (p = 0.049). The results indicated a diversity of gastrointestinal pathogens with zoonotic potential in horses and provided evidence for predictors for the infections; also, they can serve to inform horse owners and handlers regarding the possible risk of transmission of pathogens with zoonotic potential. In addition, our findings highlight the importance of continuous surveillance for zoonotic pathogens in domestic animals. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Salmonella is a major cause of foodborne diseases worldwide. Conventional rapid assays for detecting Salmonella in real samples often encounter severe matrix interference or detect a limited number of species of a genus, resulting in inaccurate detection. In this study, we developed a method that combined phage-based magnetic capture with real-time recombinase polymerase amplification (RPA) for the rapid, highly sensitive, and specific detection of Salmonella in milk with an ultra-low detection limit. The Felix O-1 phage-conjugated magnetic beads (O-1 pMBs) synthesized in this method showed excellent capture ability for Salmonella spp. and ideal specificity for non- Salmonella strains. After O-1 pMBs-based magnetic separation, the limit of detection of the real-time RPA assay was 50 cfu/mL in milk samples, which was significantly increased by a magnitude of 3 to 4 orders. The method exhibited a high sensitivity (compatibility) of 100% (14/14) for all tested Salmonella serotype strains and an ideal specificity (exclusivity) of 100% (7/7) for the tested non- Salmonella strains. The entire detection process, including Salmonella capture, DNA extraction, and real-time RPA detection, was completed within 1.5 h. Furthermore, milk samples spiked with 10 cfu/25 mL of Salmonella were detected positive after being cultured in buffered peptone water for only 3 h. Therefore, the proposed method could be an alternative for the rapid and accurate detection of Salmonella. [ABSTRACT FROM AUTHOR]

Adherence to both cellular and abiotic surfaces is a crucial step in the interaction of bacterial pathogens and commensals with their hosts. Bacterial surface structures known as fimbriae or pili play a fundamental role in the early colonization stages by providing specificity or tropism. Among the various fimbrial families, the chaperone-usher family has been extensively studied due to its ubiquity, diversity, and abundance. This family is named after the components that facilitate their biogenesis. Type 1 fimbria and P pilus, two chaperone-usher fimbriae associated with urinary tract infections, have been thoroughly investigated and serve as prototypes that have laid the foundations for understanding the biogenesis of this fimbrial family. Additionally, the study of the mechanisms regulating their expression has also been a subject of great interest, revealing that the regulation of the expression of the genes encoding these structures is a complex and diverse process, involving both common global regulators and those specific to each operon. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovars are zoonotic bacterial that cause foodborne enteritis. Due to bacteria's antibiotic resistance, using bacteriophages for biocontrol and treatment is a new therapeutic approach. In this study, we isolated, characterized, and analyzed the genome of vB_SenS_TUMS_E19 (E19), a broad host range Salmonella bacteriophage, and evaluated the influence of E19 on liquid eggs infected with Salmonella enterica serovar Enteritidis. Transmission electron microscopy showed that the isolated bacteriophage had a siphovirus morphotype. E19 showed rapid adsorption (92% in 5 min), a short latent period (18 min), a large burst size (156 PFU per cell), and a broad host range against different Salmonella enterica serovars. Whole-genome sequencing analysis indicated that the isolated phage had a 42 813 bp long genome with 49.8% G + C content. Neither tRNA genes nor those associated with antibiotic resistance, virulence factors, or lysogenic formation were detected in the genome. The efficacy of E19 was evaluated in liquid eggs inoculated with S. Enteritidis at 4 and 25 °C, and results showed that it could effectively eradicate S. Enteritidis in just 30 min and prevented its growth up to 72 h. Our findings indicate that E19 can be an alternative to a preservative to control Salmonella in food samples and help prevent and treat salmonellosis. [ABSTRACT FROM AUTHOR]

This study aimed to determine the contamination level, seasonal distribution and the persistence of Salmonella sp, Vibrio cholera, and E. coli in well waters located near municipal solid and liquid waste dumpsites in Zaria, Kaduna State, Nigeria. A total of 186 samples: well water samples (96), soils from waste dump sites (72) and waste water (18), were collected for this study. Samples were plated using freshly prepared molten plate count, Eosine methylene blue agars, poured and swirled properly for a uniform mixture. The presence of E. coli, Salmonella, and Vibrio sp were determined for the two seasons (dry and wet). The bacteria count revealed a significant difference between well waters, soil samples, liquid waste and the control (total plate count - p < 0.005; 0.0001, total coliform count - p < 0.005; 0.0021). All the sampled well water had coliform counts higher than the recommended standard. The counts were higher in the wet season than the dry season. Out of a total of 125 suspected isolates tested, 70 (56%) were positive for Vibrio cholerae, out of this, 38 (54.3%), 28 (40%) and four (5.7%) isolates were from well water, solid waste dumps and liquid waste respectively. Out of the 177 suspected E. coli isolates from well water, solid waste dumps and liquid waste tested, 162 (91.5%) were positive with 82 (50.6%) of the positive E. coli further confirmed to be E. coli 0157:H7. The results showed significant (p < 0.05) statistical difference between the wet and the dry seasons for all the water samples studied and between control and the other well water samples. Adequate treatments of well water, as well as public health education are highly recommended. [ABSTRACT FROM AUTHOR]

Background: Leafy greens, particularly romaine lettuce, are often associated with outbreaks due to their susceptibility to contamination from various environmental sources. This study aimed to evaluate the presence of E. coli, Salmonella, copper, nickel, zinc, and manganese in irrigation water, lettuce leaves, and agricultural soil in the Litani River Basin (LRB), Lebanon. Method: Samples were collected from five demonstration plots employing different agricultural practices. Heavy metal concentrations were determined using atomic absorption spectrometry, while E. coli and Salmonella testing were conducted through conventional culturing techniques. The impact of E. coli contamination on seed germination and the interaction effects between E. coli and heavy metals were also examined. The study also compared the effectiveness of various irrigation systems in reducing bacterial contamination. Results: The results demonstrated that contamination levels varied significantly across the plots and irrigation types. This variation underscores the necessity of site-specific mitigation strategies to enhance food safety. Our findings highlight the importance of selecting appropriate irrigation methods and implementing tailored agricultural practices to minimize the risk of contamination. Conclusion: This research provides valuable insights for optimizing agricultural practices in the LRB to ensure food safety and environmental sustainability. [ABSTRACT FROM AUTHOR]

Background: Foodborne diseases (FBDs) represent a significant risk to public health, with nearly one in ten people falling ill every year globally. The large incidence of foodborne diseases in African low- and middle-income countries (LMIC) shows the immediate need for action, but there is still far to a robust and efficient outbreak detection system. The detection of outbreak heavily relies on clinical diagnosis, which are often delayed or ignored due to resource limitations and inadequate surveillance systems. Methods: In total, 68 samples of non-typhoidal Salmonella isolates from human, animal and environmental sources collected between November 2021 and January 2023 were analyzed using sequencing methods to infer phylogenetic relationships between the samples. A source attribution model using a machine-learning logit-boost that predicted the likely source of infection for 20 cases of human salmonellosis was also run and compared with the results of the cluster detection. Results: Three clusters of samples with close relation (SNP difference < 30) were identified as non-typhoidal Salmonella in Harar town and Kersa district, Ethiopia. These three clusters were comprised of isolates from different sources, including at least two human isolates. The isolates within each cluster showed identical serovar and sequence type (ST), with few exceptions in cluster 3. The close proximity of the samples suggested the occurrence of three potential outbreaks of non-typhoidal Salmonella in the region. The results of the source attribution model found that human cases of salmonellosis could primarily be attributed to bovine meat, which the results of the phylogenetic analysis corroborated. Conclusions: The findings of this study suggested the occurrence of three possible outbreaks of non-typhoidal Salmonella in eastern Ethiopia, emphasizing the importance of targeted intervention of food safety protocols in LMICs. It also highlighted the potential of integrated surveillance for detecting outbreak and identifying the most probable source. Source attribution models in combination with other epidemiological methods is recommended as part of a more robust and integrated surveillance system for foodborne diseases. [ABSTRACT FROM AUTHOR]

Practical Application The present study investigated the microbiological safety of the increasingly popular plant‐based milk alternatives. No (10/27) or only very low microbial counts (17/27) were detected in the tested products. These were mainly identified as spore formers via MALDI‐ToF‐MS. Three products contained Bacillus cereus group isolates, which were able to form considerable amounts of enterotoxins and exhibited cytotoxicity towards CaCo‐2 cells. Preliminary tests showed good growth of B. cereus, Listeria monocytogenes, and Salmonella enterica in all tested products (maximum bacterial counts: 5 × 1012 cfu/mL). These experiments also revealed strain‐, time‐, and temperature‐, but especially product‐specific enterotoxin production of B. cereus. In propagation and persistence tests according to DIN EN ISO 20976‐1:2019‐09, rapid bacterial proliferation was also detected in all products. B. cereus generally showed lower bacterial counts (106–107 cfu/mL) compared to L. monocytogenes and S. enterica (108–109 cfu/mL), but was detectable in a larger number of products over the test period of 6 weeks. pH values decreased (20/27) over time and visual and/or olfactory alterations (24/27) were observed. The present study provides information on the occurrence, growth and persistence of pathogenic bacteria in plant‐based drinking milk alternatives. It also points out that the accompanying changes in pH, odor, and appearance are not necessarily recognizable to the consumer.The present study contributes to the understanding of the microbial risk related to plant‐based drinking milk alternatives. It is crucial that the manufacturer ensures that particularly spore formers have been effectively eliminated from the products. Among them, especially toxin‐producing bacteria can pose a risk to the consumer, as these products promote proliferation and persistence of the bacteria. [ABSTRACT FROM AUTHOR]

Rapid and accurate identification of Salmonella enterica serotypes Typhi and Paratyphi (A, B and C), the causal agents of enteric fever, is critical for timely treatment, case management and evaluation of health policies in low and middle-income countries where the disease still remains a serious public health problem. The present study describes the development of a multiplex assay (EFMAtyping) for simultaneous identification of pathogens causing typhoid and paratyphoid fever in a single reaction by the MeltArray approach, which could be finished within 2.5 h. Seven specific genes were chosen for differentiation of typhoidal and nontyphoidal Salmonella. All gene targets were able to be detected by the EFMAtyping assay, with expected Tm values and without cross-reactivity to other relevant Salmonella serovars. The limit of detection (LOD) for all gene targets was 50 copies per reaction. The LOD reached 102–103 CFU/ml for each pathogen in simulated clinical samples. The largest standard deviation value for mean Tm was below 0.5 °C. This newly developed EFMAtyping assay was further evaluated by testing 551 clinical Salmonella isolates, corroborated in parallel by the traditional Salmonella identification workflow, and serotype prediction was enabled by whole-genome sequencing. Compared to the traditional method, our results exhibited 100% of specificity and greater than 96% of sensitivity with a kappa correlation ranging from 0.96 to 1.00. Thus, the EFMAtyping assay provides a rapid, high throughput, and promising tool for public health laboratories to monitor typhoid and paratyphoid fever. [ABSTRACT FROM AUTHOR]

Specialty mushrooms have been implicated in foodborne illness outbreaks in the U.S. in recent years. These mushrooms are available to consumers in both their fresh and dried states. Dehydrating mushrooms is a convenient way to increase shelf life. The dehydration process results in a lowered water activity (aw) of the commodity, creating an environment where both spoilage and pathogenic bacteria cannot proliferate. Prior to food preparation and consumption, these mushrooms are typically rehydrated and possibly stored for later use which could lead to increased levels of pathogens. This study examined the survival and growth of Listeria monocytogenes and Salmonella enterica on dehydrated enoki and wood ear mushrooms during rehydration and subsequent storage. Mushrooms were heat dehydrated, inoculated at 3 log CFU/g, and rehydrated at either 5 or 25°C for 2 h. Rehydrated mushrooms were stored at 5, 10, or 25°C for up to 14 d. L. monocytogenes and S. enterica survived on enoki and wood ear mushroom types during rehydration at 5 and 25°C, with populations often <2.39 log CFU/g. During subsequent storage, no growth was observed on wood ear mushrooms, regardless of the rehydration or storage temperature, with populations remaining <2.39 log CFU/g for both pathogens. When stored at 5°C, no growth was observed for either pathogen on enoki mushrooms. During storage at 10 and 25°C, pathogen growth rates and populations after 14 d were generally significantly higher on the enoki mushrooms rehydrated at 25°C; the highest growth rate (3.56 ± 0.75 log CFU/g/d) and population (9.48 ± 0.62 log CFU/g) after 14 d for either pathogen was observed by S. enterica at 25°C storage temperature. Results indicate a marked difference in pathogen survival and proliferation on the two specialty mushrooms examined in this study and highlight the need for individual product assessments. Data can be used to assist in informing guidelines for time and temperature control for the safety of rehydrated mushrooms. [ABSTRACT FROM AUTHOR]

In mammals, enteric salmonellas can use tetrathionate (ttr), formed as a by-product from the inflammatory process in the intestine, as electron acceptor in anaerobic respiration, and it can fuel its energy metabolism by degrading the microbial fermentation product 1,2-propanediol. However, recent studies have shown that this mechanism is not important for Salmonella infection in the intestine of poultry, while it prolongs the persistence of Salmonella at systemic sites in this species. In the current study, we show that ΔttrApduA strains of Salmonella enterica have lower net survival within chicken-derived HD-11 macrophages, as CFU was only 2.3% (S. Enteritidis ΔttrApduA), 2.3% (S. Heidelberg ΔttrApduA), and 3.0% (S. Typhimurium ΔttrApduA) compared to wild-type strains after 24 h inside HD-11 macrophage cells. The difference was not related to increased lysis of macrophages, and deletion of ttrA and pduA did not impair the ability of the strains to grow anaerobically. Further studies are indicated to determine the reason why Salmonella ΔttrApduA strains survive less well inside macrophage cell lines. [ABSTRACT FROM AUTHOR]

Simple Summary: One of the main concerns associated with phage applications is the potential emergence of bacterial variants exhibiting reduced susceptibility to bacteriophages, which may jeopardize the success of such applications, as occurs with antibiotics. In this work, we studied the emergence of reduced-phage-susceptibility variants in broiler trials challenged with Salmonella enterica serovar Infantis and treated with the PhagoVet product. We characterized the bacteriophages composing the PhagoVet product at both a microscopic and genomic level, which displayed a broad host range of infection against 271 strains representing 18 Salmonella serovars. Our results indicate that the emergence of reduced-phage-susceptibility variants is unlikely to compromise the efficacy of oral PhagoVet against S. Infantis. Salmonella enterica serovar Infantis (S. Infantis) poses a growing issue in the poultry sector, with phage-based products emerging as a safe and effective control measure. This study investigated the emergence of reduced-phage-susceptibility variants (RPSV) of S. Infantis in PhagoVet-treated broilers, given that RPSV could undermine phage treatment efficacy. The bacteriophages in the PhagoVet product were characterized using transmission electron microscopy (TEM), genome sequencing, and infection profiling. Furthermore, two broiler trials were conducted: a challenge group (T1) and a challenge-and-treated group (T2). The S. Infantis infective dose was set at 104 and 106 colony-forming units (CFUs) per animal, with PhagoVet administration at 106 and 108 plaque-forming units (PFUs) per animal, in Trials 1 and 2, respectively. The results revealed that the four PhagoVet bacteriophages belonged to different genera. PhagoVet evidenced broad-spectrum efficacy against 271 strains representing 18 Salmonella serovars. In Trial 1, PhagoVet reduced bacterial counts in feces to nearly undetectable levels by day 42, with no RPSV detected. However, in Trial 2, three and five RPSVs were detected in feces and ceca, respectively. Consequently, PhagoVet demonstrated efficacy against S. Infantis in broilers, and the potential impact of RPSV is deemed unlikely to compromise its efficacy. [ABSTRACT FROM AUTHOR]

High pressure processing (HPP) is a non-thermal technology with emerging application within the fruit and vegetable sector. The impact of the enumeration agar on the recorded HPP inactivation of L. monocytogenes, Salmonella spp. and E. coli in banana–apple and apple purees was evaluated. Additionally, the HPP inactivation and sublethal injury was quantified in apple puree, considering the impact of acid exposure (24 h before HPP) and sampling time. Inoculated purees were pressurized at 300 MPa for 2 min. Enumeration was performed immediately and 24 h after HPP. HPP inactivation was 0.9-to-4.5-fold higher in apple than banana–apple puree. Compared with nutrient-rich media, selective agar enumeration overestimated the inactivation. HPP inactivation and sublethal injury of L. monocytogenes, Salmonella and E. coli was variable, mainly dependent on the exposure to acid and the sampling time. The 24 h-delayed enumeration slightly increased the inactivation. In apple puree, the CECT5947 strain of E. coli O157:H7 was the most piezo-resistant strain (1.5 log reduction), while L. monocytogenes Scott A was the most piezo-sensitive (6-log reduction when exposed to acid and sampled 24 h after HPP). All the studied factors should be taken into account when designing HPP treatments, performing product-specific validation studies and setting verification procedures. [ABSTRACT FROM AUTHOR]

Hatcheries, where eggs from multiple breeder farms are incubated and hatched before being sent to different broiler farms, represent a nexus point in the commercial production of broilers in the United States. Considering all downstream microbial quality and safety aspects of broiler production (live production, processing, consumer use) can be potentially affected by the hatchery, a better understanding of microbial ecology within commercial hatcheries is essential. Therefore, a commercial broiler hatchery was biomapped using 16S rRNA amplicon-based microbiome analyses of four sample type categories (Air, Egg, Water, Facility) across five different places in the pre-hatch, hatch, and post-hatch areas. While distinct microbiota were found for each sample type category and hatchery area, microbial community analyses revealed that Egg microbiota trended towards clustering with the facility-related samples when moving from the prehatch to post-hatch areas, highlighting the potential effect of the hatchery environment in shaping the pre-harvest broiler-related microbiota. Prevalence analyses revealed 20 ASVs (Core20) present in the core microbiota of all sample types and areas, with each ASV possessing a unique distribution throughout the hatchery. Interestingly, three Enterobacteriaceae ASVs were in the Core20, including Salmonella. Subsequent analyses showed that Salmonella, while a minor prehatch and hatch Core20ASV, dominated the Enterobacteriaceae niche and total microbiota in the chick pad feces in the post-hatch area of the hatchery, and the presence of this Salmonella ASV in the post-hatch feces was associated with swabs of breakroom tables. These findings highlight the complexity of commercial hatchery microbiota, including identifying chick pad feces and breakroom tables as potentially important sampling or disinfection targets for hatchery managers to focus their Salmonella mitigation efforts to reduce loads entering live production farms. [ABSTRACT FROM AUTHOR]

Understanding the dynamic evolution of Salmonella is vital for effective bacterial infection management. This study explores the role of the flexible genome, organised in regions of genomic plasticity (RGP), in shaping the pathogenicity of Salmonella lineages. Through comprehensive genomic analysis of 12,244 Salmonella spp. genomes covering 2 species, 6 subspecies, and 46 serovars, we uncover distinct integration patterns of pathogenicity-related gene clusters into RGP, challenging traditional views of gene distribution. These RGP exhibit distinct preferences for specific genomic spots, and the presence or absence of such spots across Salmonella lineages profoundly shapes strain pathogenicity. RGP preferences are guided by conserved flanking genes surrounding integration spots, implicating their involvement in regulatory networks and functional synergies with integrated gene clusters. Additionally, we emphasise the multifaceted contributions of plasmids and prophages to the pathogenicity of diverse Salmonella lineages. Overall, this study provides a comprehensive blueprint of the pathogenicity potential of Salmonella. This unique insight identifies genomic spots in nonpathogenic lineages that hold the potential for harbouring pathogenicity genes, providing a foundation for predicting future adaptations and developing targeted strategies against emerging human pathogenic strains. Effective management of Salmonella infections requires understanding its dynamic evolution. This study shows how specific genomic regions influence the distribution of pathogenicity factors in Salmonella, highlighting the potential for targeted infection control strategies. [ABSTRACT FROM AUTHOR]

Background: The increased resistance rate of Salmonella to third-generation cephalosporins represented by ceftriaxone (CRO) may result in the failure of the empirical use of third-generation cephalosporins for the treatment of Salmonella infection in children. The present study was conducted to evaluate a novel method for the rapid detection of CRO-resistant Salmonella (CRS). Methods: We introduced the concept of the ratio of optical density (ROD) with and without CRO and combined it with matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF MS) to establish a new protocol for the rapid detection of CRS. Results: The optimal incubation time and CRO concentration determined by the model strain test were 2 h and 8 µg/ml, respectively. We then conducted confirmatory tests on 120 clinical strains. According to the receiver operating characteristic curve analysis, the ROD cutoff value for distinguishing CRS and non-CRS strains was 0.818 [area under the curve: 1.000; 95% confidence interval: 0.970–1.000; sensitivity: 100.00%; specificity: 100%; P < 10− 3]. Conclusions: In conclusion, the protocol for the combined ROD and MALDI-TOF MS represents a rapid, accurate, and economical method for the detection of CRS. [ABSTRACT FROM AUTHOR]

Salmonella, the prevailing zoonotic pathogen within the Enterobacteriaceae family, holds the foremost position in global bacterial poisoning incidents, thereby signifying its paramount importance in public health. Consequently, the imperative for expeditious and uncomplicated detection techniques for Salmonella in food is underscored. After more than two decades of development, loop-mediated isothermal amplification (LAMP) has emerged as a potent adjunct to the polymerase chain reaction, demonstrating significant advantages in the realm of isothermal amplification. Its growing prominence is evident in the increasing number of reports on its application in the rapid detection of Salmonella. This paper provides a systematic exposition of the technical principles and characteristics of LAMP, along with an overview of the research progress made in the rapid detection of Salmonella using LAMP and its derivatives. Additionally, the target genes reported in various levels, including Salmonella genus, species, serogroup, and serotype, are summarized, aiming to offer a valuable reference for the advancement of LAMP application in Salmonella detection. Finally, we look forward to the development direction of LAMP and expect more competitive methods to provide strong support for food safety applications. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to develop and evaluate the effectiveness of a water-soluble microencapsulation method for probiotic strains using gum Arabic (GA) and skim milk (SKM) over a three-month storage period following processing. Methods: Four strains of Pediococcus acidilactici (BYF26, BYF20, BF9, and BF14) that were typical lactic acid bacteria (LAB) isolated from the chicken gut were mixed with different ratios of GA and SKM as coating agents before spray drying at an inlet temperature 140°C. After processing, the survivability and probiotic qualities of the strains were assessed from two weeks to three months of storage at varied temperatures, and de-encapsulation was performed to confirm the soluble properties. Finally, the antibacterial activity of the probiotics was assessed under simulated gastrointestinal conditions. Results: As shown by scanning electron microscopy, spray-drying produced a spherical, white-yellow powder. The encapsulation efficacy (percent) was greatest for a coating containing a combination of 30% gum Arabic: 30% skim milk (w/v) (GA:SKM30) compared to lower concentrations of the two ingredients (p<0.05). Coating with GA:SKM30 (w/v) significantly enhanced (p<0.05) BYF26 survival under simulated gastrointestinal conditions (pH 2.5 to 3) and maintained higher survival rates compared to non-encapsulated cells under an artificial intestinal juices condition of pH 6. De-encapsulation tests indicated that the encapsulated powder dissolved in water while keeping viable cell counts within the effective range of 106 for 6 hours. In addition, following three months storage at 4°C, microencapsulation of BYF26 in GA:SKM30 maintained both the number of viable cells (p<0.05) and the preparation's antibacterial efficacy against pathogenic bacteria, specifically strains of Salmonella. Conclusion: Our prototype water-soluble probiotic microencapsulation GA:SKM30 effectively maintains LAB characteristics and survival rates, demonstrating its potential for use in preserving probiotic strains that can be used in chickens and potentially in other livestock. [ABSTRACT FROM AUTHOR]

Salmonella Typhimurium (S. Typhimurium) contamination poses a significant challenge to breeder egg hatchability and chick health, necessitating the exploration of alternative disinfection methods. This study investigates the potential of phage vB_SPuM_SP02 (SP02) as a novel disinfectant for breeder eggs contaminated with S. Typhimurium SM022. Phage SP02 was isolated from poultry farm effluent and characterized for morphology, biological properties, and genome properties. Experimental groups of specific pathogen-free (SPF) eggs were treated with Salmonella and phage SP02, and efficacy was assessed through hatching rates, chick survival, weight, Salmonella load, immune organ indices, and intestinal flora. Phage treatment effectively eradicated Salmonella contamination on eggshells within 12 h, resulting in increased hatching and survival rates compared to controls. Furthermore, phage treatment mitigated weight loss and tissue Salmonella load in chicks without causing immune organ damage while reducing Salmonella spp. abundance in the intestinal tract. This study demonstrates the potential of phage SP02 as an eco-friendly and efficient disinfectant for S. Typhimurium-contaminated breeder eggs, offering promising prospects for practical application in poultry production. [ABSTRACT FROM AUTHOR]

Salmonellosis associated with reptiles is a well‐researched topic, particularly in China and the United States, but it occurs less frequently in Europe. The growth of the human population and changes in the environment could potentially increase the interaction between humans and free‐living reptiles, which are an unidentified source of Salmonella species. In this study, we sought to explore this issue by comparing the microbiota of free‐living European grass snakes, scientifically known as Natrix natrix, with that of captive banded water snakes, or Nerodia fasciata. We were able to isolate 27 strains of Salmonella species from cloacal swabs of 59 N. natrix and 3 strains from 10 N. fasciata. Our findings revealed that free‐living snakes can carry strains of Salmonella species that are resistant to normal human serum (NHS). In contrast, all the Salmonella species strains isolated from N. fasciata were sensitive to the action of the NHS, further supporting our findings. We identified two serovars from N. natrix: Salmonella enterica subspecies diarizonae and S. enterica subspecies houtenae. Additionally, we identified three different virulotypes (VT) with invA, sipB, prgH, orgA, tolC, iroN, sitC, sifA, sopB, spiA, cdtB and msgA genes, and β‐galactosidase synthesised by 23 serovars. The identification of Salmonella species in terms of their VT is a relatively unknown aspect of their pathology. This can be specific to the serovar and pathovar and could be a result of adaptation to a new host or environment. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to determine the effects of using UV light instead of formaldehyde in disinfection of hatching eggs on the microbial load, shell and yolk compositions, embryo development, hatching results and chick characteristics. 552 hatching eggs were divided into formaldehyde fumigation and disinfection with UV groups. After disinfection, bacteriological growth was not observed in groups. While the difference between the groups in terms of hatching results was insignificant, it was determined that the incubation period in the UV group was shorter than that of formaldehyde group. On the hatching day, relative chick weight and weight of bursa Fabricus were found to be higher in the UV group. UV light can be used as an alternative to formaldehyde as disinfection of hatching eggs because it is easy to use and does not cause any negative effects on egg shell structure, embryo development, hatching results and chick characteristics. [ABSTRACT FROM AUTHOR]

Food‐related stresses such as heating and freezing may influence the biofilm formation ability of bacteria. This study aimed to investigate the main and interactive effects of food‐related stresses on the biofilm formation potential of Salmonella strains isolated from meat. Salmonella enteritidis, Salmonella typhi, and Salmonella typhimurium were subjected to osmotic, acid, heat, cold, and freezing stresses. The colorimetric microtiter plate method was used to measure the biofilm formation ability as a response to the stresses. Among the main effects, freezing time had the most significant effect on the biofilm formation responses of three Salmonella serovars. Freezing reduced the biofilm formation ability of Salmonella typhimurium and Salmonella enteritidis but increased that of Salmonella typhi (p < 0.05). Among the interaction effects, the most significant effect on the biofilm formation response of Salmonella typhi was the interaction between pH and heat, which had a negative effect on the biofilm formation response. In contrast, the interaction between osmotic pressure and cold stresses was the most significant interactive effect on the biofilm formation responses of Salmonella enteritidis and Salmonella typhimurium, which had an increasing effect. This study concluded that the food‐related stresses could change the biofilm formation capacity of Salmonella serotypes, and each serotype might show different biofilm formation abilities in response to different stresses. [ABSTRACT FROM AUTHOR]

Foodborne pathogens pose a persistent threat in broiler chicken production, particularly during the slaughter process, where contamination with zoonotic pathogens remains a concern. This study focuses on the potential of organic acids, such as formic and lactic acid, and the oxidizing agent peracetic acid, to decontaminate scalding water and enhance the hygiene of chicken carcasses. We conducted suspension tests introducing various organic loads to mirror the conditions of practical scalding water. Additionally, the surface tests were performed on chicken skin. Both methods were further tested in an experimental slaughtering facility. In suspension tests, the organic acids achieved impressive decontamination, with a 5‐log10 reduction of the test organisms Enterococcus hirae, Salmonella Typhimurium and Campylobacter jejuni at minimal concentrations (between 0.04% and 2% for formic acid; between 0.1% and 4.5% for lactic acid). Peracetic acid also effectively sanitized model water and chicken skin, even when used in low concentrations (between 0.001% and 0.1%), both in the laboratory‐based testing and in the experimental slaughtering facility. These results suggest that the tested disinfectants can effectively sanitize process water, even under conditions mimicking practical scalding water with organic matter. Peracetic acid, in particular, proved highly effective in improving chicken skin hygiene even at low concentrations. [ABSTRACT FROM AUTHOR]

The consumption of fresh and fresh‐cut fruits and vegetables, such as carrots, has increased for the last decades for a healthy life and an adequate diet, but concerns regarding the microbial safety of them have been raised. The present study was conducted to develop predictive models for Salmonella spp. in grated carrots. The results showed that Salmonella spp. did not display growth at 5°C, but it grew in grated carrots at other temperatures (10, 15, 20, 25, and 37°C) for both inoculum levels. Also, the inoculum levels affected the growth of this pathogen in grated carrots when the storage temperatures ranged from 15 to 25°C. The theoretical minimum temperatures calculated using the Huang model were 3.48 and 5.79°C for inoculum levels of 101 and 102 CFU/g, respectively. The primary and secondary models performed well in terms of agreement between experimental and estimated values. Furthermore, compared to the Ratkowsky model, the theoretical minimum temperature was given a more reasonable value using the Huang model. The models developed in the present study will be a useful input for future quantitative microbial risk assessment to appraise the proliferation of Salmonella spp. in grated carrots throughout the production process, storage, and distribution. [ABSTRACT FROM AUTHOR]

Objectives To characterize bla NDM-carrying Salmonella recovered from a pig slaughterhouse. Methods In this study, 46 environment samples were collected from a slaughterhouse in China, and screened for carbapenem-resistant Enterobacterales. WGS, antimicrobial susceptibility testing and conjugation experiments were carried out to identify the isolates' resistance phenotypes and genetic characteristics. The phylogenetic relatedness of the Salmonella isolates obtained in this study and Salmonella (ST34 and ST29) in GenBank was determined. Results Two ST34 Salmonella Typhimurium and one ST29 Salmonella Stanley, recovered from three environmental samples (6.52%), were positive for bla NDM-1 and bla NDM-5, respectively. The two ST34 S. Typhimurium strains exhibited a close relationship (10–36 SNPs) with two human-derived bla NDM-1-bearing isolates from China (Hong Kong and Guangxi Province) and two bla NDM-negative ST34 Salmonella strains from the UK. The bla NDM-1 genes were located on IncHI2/ST3 plasmids. The capture of bla NDM-1 by the IncHI2/ST3 plasmid seems to be due to homologous recombination mediated by circular structures, as the genetic arrangements of the bla NDM-1 gene contain two IS 26 elements of the same orientation. The bla NDM-5 gene was also carried by the IncHI2/ST3 plasmid, which shares highly similar structures with other bla NDM-5-bearing IncHI2/ST3 plasmids from other sources (fish, chicken, duck, human). Conclusions This is the first report of a bla NDM-5-carrying IncHI2/ST3 plasmid in Salmonella. The clonal spread of NDM-1-producing ST34 S. Typhimurium across human and animal-associated environments, and the widespread dissemination of epidemic bla NDM-5-carrying IncHI2/ST3 plasmids among Enterobacteriaceae in China indicate the potential of further dissemination of bla NDM among Salmonella , which poses a threat to public health. [ABSTRACT FROM AUTHOR]

Objectives To explore the feasibility of linking data from enhanced surveillance patient questionnaires from each enteric fever case in England with genome sequencing data, including antimicrobial resistance (AMR) profiles, from the corresponding isolate of typhoidal salmonellae. Methods After linking data we interrogated the merged dataset and assessed the utility of passive surveillance data to match and monitor antimicrobial treatment regimens in enteric fever patients with the AMR profiles of the infectious agent. Results A high proportion of cases were given antibiotics (n  = 1230/1415; 86.9%); half of the cases stated the class of antibiotic they were given (n  = 630/1239) and half were prescribed cephalosporins (n  = 316/630). Reported treatment with a combination of antibiotics increased with symptom severity. Nearly half of isolates (n  = 644/1415; 45.5%) had mutations conferring resistance to ciprofloxacin. Based on genome-derived AMR profiles, typhoidal salmonellae isolates inferred to be susceptible to the recommended first-line antimicrobials were twice as likely to be isolated from individuals residing in the least deprived areas compared with the most deprived (n  = 26/169; 15.4% versus n  = 32/442; 7.2%). Conclusions Due to the high proportion of missing data obtained from patient interviews, we recommend a more transparent and systematic approach to recording the antibiotic prescription details by healthcare professionals in primary and secondary care. A more robust approach to data capture at this point in the care pathway would enable us to audit inconsistencies in the prescribing algorithms across England and ensure equitable treatment across all sections of society. Integrating prescribing data with the genome-derived AMR profiles of the causative agent at the individual patient level provides an opportunity to monitor the impact of treatment on clinical outcomes, and to promote best practice in real time. [ABSTRACT FROM AUTHOR]

Aims: Salmonella infections are significant causes of foodborne outbreaks in the European Union. This study investigates a sudden increase in gastroenteritis patients in the hospital district of Central Finland in June 2021. The primary aim was to study the outbreak's magnitude and source of the outbreak. Methods and Results: Epidemiological, microbiological, environmental and traceback investigations were conducted. Over 700 persons fell ill during the outbreak caused by Salmonella Typhimurium associated with a daycare lunch. Similar S. Typhimurium was found in the patients and a vegetable mix containing iceberg lettuce, cucumber and peas served during lunch. The traceback investigation revealed that the batch information of vegetables from the wholesaler was not complete. The wholesaler had received quality complaints about the iceberg lettuce from the central kitchen. The manufacturer did not test the suspected batch for Salmonella since the production plant had given a certificate declaring it Salmonella negative. Conclusions: The most suspect ingredient was one batch of iceberg lettuce due to quality complaints. The lettuce had not been served in two daycare centres without cases. We recommend that in order to enable thorough microbiological investigation, institutional kitchens store the food samples separately as part of the internal quality control and that food items should always be tested when Salmonella contamination in an outbreak is suspected. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the phenotypic and genotypic responses of Salmonella Typhimurium ATCC 19585 (ST) and Staphylococcus aureus KACC 13236 (SA) preadapted to sublethal concentrations of lactic acid (LA) and sodium chloride (NaCl) for 48 hr at 37°C, followed by re-exposure to lethal concentrations of LA and NaCl for 24 hr at 37°C. ST and SA treated in a sequential and ordered manner with LA and NaCl were assigned as LA-LA, LA-NaCl, NaCl-LA, and NaCl-NaCl. The treatments, LA-LA, LA-NaCl, NaCl-LA, and NaCl-NaCl, were evaluated by antimicrobial susceptibility, bacterial fluctuation, relative fitness, zeta potential, and gene expression. The MICt/MICc ratios of LA, NaCl, CIP, GEN, and TET against ST treated with LA-LA were 1.0 to 0.8, 0.8, 0.3, 0.4, and 0.5, respectively. The MICt/MICc ratios of NaCl, CIP, GEN, and TET were between 0.5–0.8 for SA treated with LA-LA. ST treated with LA-LA and SA treated with LA-NaCl exhibited the highest coefficient of variance. The lowest relative fitness was observed at ST treated with LA-LA (0.5). ST and SA treated with LA-LA showed the lowest zeta potential. The transporter-, toxin–antitoxin system-, chaperone protein-, and SOS response-related genes were suppressed at ST and SA treated with LA-LA. The transporter-, toxin–antitoxin system-, and chaperone protein-related genes were overexpressed in SA treated with LA-NaCl, NaCl-LA, and NaCl-NaCl. The results suggest that ST and SA treated with LA-LA, LA-NaCl, NaCl-LA, and NaCl-NaCl could induce collateral sensitivity and cross-resistance. [ABSTRACT FROM AUTHOR]

1. Epidemiological surveillance of Salmonella spp. serves as a primary tool for maintaining the health of poultry flocks. Characterising circulating serotypes is crucial for implementing control and prevention measures. This study conducted phenotypic and molecular characterisation of S. enterica Pullorum, S. enterica Heidelberg, and S. enterica Corvalis isolated from broiler chickens during slaughtering. 2. All strains were susceptible to gentamicin, neomycin and norfloxacin. However, resistance rates exceeded 50% for ciprofloxacin and tiamulin, irrespective of the serotype. Approximately 64% of strains were classified as multidrug-resistant, with S. enterica Heidelberg strains exhibiting significantly higher overall resistance. The isolates demonstrated the ability to adhere and produce biofilm at a minimum of three temperatures, with S. enterica Pullorum capable of biofilm production at all temperatures encountered during poultry rearing. 3. Each strain possessed between two and seven different virulence-associated genes. Genetic similarity, as indicated by pulsed field gel electrophoresis, exceeded 90% for all three serotypes and strains were classified in the R5 ribotype by PCR, regardless of serotype. Sequencing revealed high similarity among all strains, with homology ranging from 99.61 to 100% and all were classified to a single cluster. 4. The results suggested a clonal relationship among the strains, indicating the possible circulation of a unique clonal group of S. enterica Pullorum in the southern region of Brazil. [ABSTRACT FROM AUTHOR]

Salmonella is a notoriously important pathogen that can cause human latent, acute, and chronic foodborne diseases. This work excavated a silver nanomaterial AgDAMP with a thiolate ligand as a novel composite bacteriostat to understand the inhibitory effects on Salmonella and to explore its antimicrobial mechanisms from the aspects of membrane structure damage, biofilm inhibition, and protein expression. The characterization results of its morphology, particle size, chemical bonds, elements, and crystal structure showed that AgDAMP were small-sized spherical nanoparticles with a certain crystallinity. AgDAMP could combat effectively the planktonic Salmonella, manifested as loss of membrane integrity, enhanced permeability, cytoplasmic leakage, and changes of cell morphology. Our study also suggested that AgDAMP not only significantly interfered with biofilm formation but also destroyed mature biofilm. Proteomic profiling indicated that the exposure to an inhibitory concentration of AgDAMP altered conspicuously more protein expression in Salmonella than a subinhibitory concentration. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis revealed that differentially expressed proteins (DEPs) were primarily enriched in the ribosome, ABC transporters, and biosynthesis of secondary metabolite pathways. Furthermore, we found that AgDAMP significantly altered the expression of regulators associated with cellular DNA replication, protein synthesis, membrane transport, cell motility, and oxidative stress, which affected cell growth. These data provide new prospects for the responses of Salmonella to AgDAMP exposure, indicating that AgDAMP could be used as a novel nanotechnology for the treatment of foodborne pathogens. [ABSTRACT FROM AUTHOR]

This manuscript presents a new report on the in vitro antimicrobial photo-inactivation of foodborne microorganisms (Salmonella spp. and Listeria monocytogenes) using tetra-cationic porphyrins. Isomeric tetra-cationic porphyrins (3MeTPyP, 4MeTPyP, 3PtTPyP, and 4PtTPyP) were tested, and antimicrobial activity assays were performed at specific photosensitizer concentrations under dark and white-light LED irradiation conditions. Among the tested bacterial strains, 4MeTPyP exhibited the highest efficiency, inhibiting bacterial growth within just 60 min at low concentrations (17.5 μM). The minimal inhibitory concentration of 4MeTPyP increased when reactive oxygen species scavengers were present, indicating the significant involvement of singlet oxygen species in the photooxidation mechanism. Furthermore, the checkerboard assay testing the association of 4MeTPyP showed an indifferent effect. Atomic force microscopy analyses and dynamic simulations were conducted to enhance our understanding of the interaction between this porphyrin and the strain's membrane. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the formation of immunological memory to Salmonella antigens in cows using different phenotypes of T-lymphocyte populations. The study was conducted on farms in Kazakhstan and Latvia. As part of the study, blood samples were collected from cows vaccinated against Salmonella to analyse T-lymphocyte phenotypes. A comparative study of different phenotypes of T-cell populations, including CD4+, CD8+, γδ T-cells and effector T-cells (CD45RA+ and CD45RA-), was conducted to assess their role in the formation of immunological memory. Flow cytometry and enzyme-linked immunosorbent assay (ELISA) were used to quantify T-cell populations and levels of specific antibodies. The main results showed that vaccination causes a significant increase in the population of CD4+ and CD8+ T-lymphocytes, which correlates with an increase in the level of specific antibodies to Salmonella antigens. The γδ T-cell population also showed significant activation, indicating their potential role in the formation of an immune response to Salmonella. Particular attention was devoted to effector cells of T-lymphocytes: CD45RA+ cells were actively involved in the primary immune response to Salmonella antigens, while CD45RA cells showed high activity during repeated exposure to the antigen, indicating their key role in maintaining longterm immunological memory. Comparative analysis of data from Kazakhstan and Latvia showed similar trends, indicating the universality of the observed immunological mechanisms. These findings highlight the importance of including different T-cell phenotypes in vaccination programmes to ensure more effective immunological memory in cows. Thus, this study provides valuable data on the role of different T-lymphocyte populations in the formation of immunological memory to Salmonella antigens in cows, which may contribute to the development of more effective vaccine programmes and improve the health and productivity of livestock in the regions of Kazakhstan and Latvia. [ABSTRACT FROM AUTHOR]

Background: The use of plants in the treatment of microbial diseases is increasing worldwide; especially with the increase of bacterial resistance to antibiotics and the development of new diseases that have no cure in modern medicines. Aim: This research was designed to determine the antimicrobial activities of bioactive compounds isolated from Acacia nilotica (A. nilotica) against multi-drug resistant bacteria. Methods: Acacia nilotica samples (i.e., leaves, pods, and back) were collected within Aliero local government area, in Nigeria. Metabolite extraction was performed through maceration. The obtained extract was tested in vitro against multi-drug resistant bacteria that cause diarrhea: Salmonella typhimurium, S. paratyphi, Salmonella sp, Shigella dysenteriae, Shigella sp, and Shigella flexneri, using the agar well diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the micro-plate serial dilution method. The synergistic (Pod + Leave Steam back) ethanolic crude extract was subjected to column and thin-layer chromatography (TLC) analyses. The obtained fractions were tested against multi-drugs resistance bacteria, and MIC and MBC of the fractions were also determined. Results: The results showed that the synergistic A. nilotica crude extract had the highest mean antibacterial activity recording inhibition zones that ranged from 15.0± 0.58 to 22.7± 0.33 mm. The MIC of ethanolic crude extracts ranged from 100 to 200 mg/ml, while the MBC ranged from 100 to > 400 mg/ ml. Conclusion: The antibacterial potential of the synergistic ethanolic fractions recorded higher activity that ranged from 16.7± 1.20 to 31.0±1.00 mm against all the tested bacteria, compared to the crude extracts. [ABSTRACT FROM AUTHOR]

Cloacal swab samples were collected from 350 apparently healthy commercial layers in Oyo and Osun states, Nigeria. Nine fluoroquinolone-resistant Salmonella species belonging to serovar Infantis (n=4), Heidelberg (n=3), and Saintpaul (n=2) were isolated from the sampled birds. The isolates were multidrug resistant with Multiple Antibiotic Resistance Index (MAR) ranging from 0.15 to 0.54. There was high resistance to fluoroquinolones, with 88.9% resistance to pefloxacin and ofloxacin, 77.8% to nalidixic acid and ciprofloxacin. None of the isolates were ESBL positive. All the nine isolates did not carry qnrA gene; 11.1%, 22.2% and 88.9% possessed qnrB, qnrD and qnrS, respectively. This study isolated plasmid mediated fluoroquinolone resistant rare Salmonella serovars from commercial layers in Nigeria. [ABSTRACT FROM AUTHOR]

A novel immunodetection sensing platform for Salmonella based on a CoFe-MOF-carbon nanotube composite was developed. The CoFe-MOF-CNT composite exhibited excellent electrochemical performance, providing a highly conductive and stable matrix for antibody immobilization and signal amplification. Under optimized conditions, the immunosensor demonstrated a wide linear range of 102 to 107 CFU/mL, with a low detection limit of 37 CFU/mL and a high sensitivity of 6.061 µA/log(CFU/mL). The immunosensor showed excellent specificity towards Salmonella, with a relative response of 100% for Salmonella and less than 10% for non-target bacteria. The immunosensor exhibited good reproducibility (RSD of 4.2%) and stability, retaining 88.7% of its initial response after 30 days of storage at 4 °C. The practical applicability of the immunosensor was demonstrated by analyzing spiked milk samples, with recoveries ranging from 96.7% to 105.2% and RSD less than 6.5%. [ABSTRACT FROM AUTHOR]

Since the use of antibiotics as growth promoters in animal feed has been restricted or banned in several countries, finding suitable alternatives is crucial for maintaining animal health. In this study, a novel formate acidifier named sodium diformate (NaDF) was synthesized, and the effects on growth performance and the prevention effects against Salmonella enterica serovar Pullorum infections in chickens were assessed. In broilers, NaDF supplementation improved growth performance, as evidenced by increased body weights and reduced feed conversion ratios. At 38 days of age, NaDF supplementation increased the levels of growth-hormone and ghrelin in the serum, lowered pH values in the gut, improved duodenal morphology, as shown by increased villus length/crypt depth ratios. NaDF also modulated the abundance of beneficial and harmful bacteria without changing the general microbiota diversity and short-chain fatty acids levels, which would be beneficial for maintaining gut homeostasis during its use. NaDF exhibited a broad spectrum of antibacterial activity in vitro. Supplementation with NaDF effectively decreased S. Pullorum colonization in the cecum, liver and spleen in chickens, and mitigated pathological changes in the tissues. Therefore, as a novel acidifier, NaDF can improve chicken growth performance by increasing growth-related hormones levels while maintaining the diversity of gut microbiota, and also resist intestinal bacterial infection. These results provided evidences for the application of NaDF as an effective and safe animal feed in poultry farming. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the decontamination efficacy of clove oil on broiler Pectoralis major fillets natural spoilage-flora and Salmonella contamination compared to chlorine and a commercial triple-mixture of peroxyacetic acid (PAA). Furthermore, the intervention’s impact on breast fillet shelf-life and physicochemical quality was investigated. Thirty-six fillets (fillets n = 3 × storage-period n = 6 × replication n = 2) were dipped in one of four treatments: sterile water (control), chlorine (50 ppm), clove (1.5%) or PAA (225 ppm). For Salmonella-inoculated experiment, 18 fillets were dipped per treatment (fillet n = 3 × storage-period n = 6). Overall, the PAA retarded most spoilage microflora and Salmonella growth, particularly aerobic plate count, below the unacceptable spoilage level of 6 log CfU/g for 9 chilling-days. However, specific meat quality metrics, particularly oxidative stability, were negatively impacted by PAA. Clove exhibited a lower and/or similar, but delayed, antibacterial effect on spoilage-flora and Salmonella levels than PAA, along with an impressive antioxidant protective effect on fillets attributes, particularly lightness and appearance. Chlorine at the current recommended dose did not extend shelf-life beyond six days or reduce Salmonella growth, although it generated lower yellowness, higher redness, and tenderness scores than other treatments. Treatments did not prolong the fillets shelf-life beyond 6 cooling-days due to oxidizing properties of PAA, diminished chlorine concentration, and shorter contact time of clove. Cloves could therefore be sprayed in another step before final packaging to extend contact-time and boost antioxidant and antibacterial barriers. Lower doses and shorter exposure durations seem desirable and could contribute to minimize the PAA negative oxidative effect on meat quality parameters. Article Highlights Natural and chemical antimicrobial dippings can lower broiler initial bacteria load but do not boost meat shelf life. The PAA strong antimicrobial benefits are hindered by negative oxidative impacts on the quality of broiler fillets. Pre-packaging clove application potentially maximizes preservative benefits on fillets and reducing dipping obstacles. [ABSTRACT FROM AUTHOR]

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The persistence of non-typhoidal Salmonella and Campylobacter in chicken meat is a considerable public health risk and a future challenge. This study aimed to determine the prevalence of Salmonella and Campylobacter in poultry processing lines where different chlorine concentrations were used in the chill tank. The samples were collected from four types of processing plants in Sri Lanka, considering the chlorine concentration used in the chill tank, which ranged from 2 ppm to 50 ppm. Salmonella and Campylobacter were isolated from whole carcass washings, neck skin, and cecal samples. Subsequently, an antimicrobial susceptibility test was performed for the isolates. The results revealed the overall prevalence of Salmonella and Campylobacter was 78.25% and 63.5%, respectively. Positive percentages of Salmonella and Campylobacter were high in the carcasses compared to the neck skin and ceca. The Campylobacter counts on the whole carcasses were significantly low (p < 0.001), at higher chlorine concentrations ranging from 20 to 30 ppm and 40 to 50 ppm. The pathogen prevalence in the whole carcasses was 84.7% Campylobacter coli, 39.1% Campylobacter jejuni, 71.1% Salmonella Typhimurium, and 28.8% Salmonella Infantis. The highest resistance was observed for tetracycline (63.8%) in Salmonella, while it was for gentamicin (87.8%) in Campylobacter. The prevalence percentage of multidrug-resistant Campylobacter was 51.2%, while it was 2.12% for Salmonella. The persistence of multidrug-resistant Salmonella and Campylobacter on the post-chill carcasses was highlighted in the present study as a significant public health threat that has to be addressed urgently. [ABSTRACT FROM AUTHOR]

Gut microbiota is a diverse community of microorganisms that constantly work to protect the gut against pathogens. Salmonella stands out as a notorious foodborne pathogen that interacts with gut microbes, causing an imbalance in the overall composition of microbiota and leading to dysbiosis. This review focuses on the interactions between Salmonella and the key commensal bacteria such as E. coli, Lactobacillus, Clostridium, Akkermansia, and Bacteroides. The review highlights the role of these gut bacteria and their synergy in combating Salmonella through several mechanistic interactions. These include the production of siderophores, which compete with Salmonella for essential iron; the synthesis of short-chain fatty acids (SCFAs), which exert antimicrobial effects and modulate the gut environment; the secretion of bacteriocins, which directly inhibit Salmonella growth; and the modulation of cytokine responses, which influences the host's immune reaction to infection. While much research has explored Salmonella, this review aims to better understand how specific gut bacteria engage with the pathogen, revealing distinct defense mechanisms tailored to each species and how their synergy may lead to enhanced protection against Salmonella. Furthermore, the combination of these commensal bacteria could offer promising avenues for bacteria-mediated therapy during Salmonella-induced gut infections in the future. [ABSTRACT FROM AUTHOR]