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Heliyon May 2024The use of flume tanks for tomato processing has been identified as a potential source of cross-contamination, which could result in foodborne illness. This study's...
The use of flume tanks for tomato processing has been identified as a potential source of cross-contamination, which could result in foodborne illness. This study's objective was to assess the efficacy of peroxyacetic acid (PAA) at a concentration of ≤80 mg/L in preventing cross-contamination under various organic loads in a benchtop model tomato flume tank. The stability of 80 mg/L PAA at different chemical oxygen demand (COD) levels was also tested. Tomatoes were spot inoculated with a five-serovar rifampin-resistant (rif+) cocktail (10 or 10 colony forming unit (CFU)/tomato). Inoculated (n = 3) and uninoculated (n = 9) tomatoes were introduced into the flume system containing 0-80 mg/L PAA and 0 or 300 mg/L COD. After washing for 30, 60, or 120 s, uninoculated tomatoes were sampled and analyzed for cross-contamination. All experiments were conducted in triplicate. Increasing the organic load (measured as COD) affected the stability of PAA in water with significantly faster dissociation when exposed to 300 mg/L COD. The concentration of PAA, inoculum level, COD levels, and time intervals were all significant factors that affected cross-contamination. Cross-contamination occurred at the high inoculum level (10 CFU/tomato) even when 80 mg/L PAA was present in the model flume tank, regardless of the organic load level. When the tomatoes were contaminated at a level of 10 CFU/tomato, concentrations as low as 5 mg/L of PAA were effective in preventing cross-contamination at 0 mg/L COD; however, 100 % tomatoes (9/9) were positive when the organic load increased to 300 mg/L COD. When the PAA concentration was increased to 10 mg/L, it effectively prevented cross-contamination in the tank, regardless of the presence of organic load. These results suggest that using PAA at concentrations below the maximum limit remains effective in limiting bacterial cross-contamination and offers a more environment-friendly option for tomato packinghouse operators.
PubMed: 38813225
DOI: 10.1016/j.heliyon.2024.e31521 -
Frontiers in Microbiology 2024Probiotic bacteria have been proposed as an alternative to antibiotics for the control of antimicrobial resistant enteric pathogens. The mechanistic details of this...
Probiotic bacteria have been proposed as an alternative to antibiotics for the control of antimicrobial resistant enteric pathogens. The mechanistic details of this approach remain unclear, in part because pathogen reduction appears to be both strain and ecology dependent. Here we tested the ability of five probiotic strains, including some from common probiotic genera and , to reduce binding of sv. Typhimurium to epithelial cells subsp. emerged as a promising strain; however, Typhimurium infection outcome in epithelial cells was dependent on inoculation order, with unable to rescue host cells from preceding or concurrent infection. We further investigated the complex mechanisms underlying this interaction between , Typhimurium, and epithelial cells using a multi-omics approach that included gene expression and altered metabolism via metabolomics. Incubation with repressed apoptotic pathways and induced anti-inflammatory cascades in epithelial cells. In contrast, co-incubation with increased in Typhimurium the expression of virulence factors, induced anaerobic metabolism, and repressed components of arginine metabolism as well as altering the metabolic profile. Concurrent application of the probiotic and pathogen notably generated metabolic profiles more similar to that of the probiotic alone than to the pathogen, indicating a central role for metabolism in modulating probiotic-pathogen-host interactions. Together these data imply crosstalk via small molecules between the epithelial cells, pathogen and probiotic that consistently demonstrated unique molecular mechanisms specific probiotic/pathogen the individual associations.
PubMed: 38812689
DOI: 10.3389/fmicb.2024.1387498 -
Microbiology Resource Announcements May 2024We report here the complete genome of one Agona strain isolated in 2017 from a dried milk powder in France.
We report here the complete genome of one Agona strain isolated in 2017 from a dried milk powder in France.
PubMed: 38809066
DOI: 10.1128/mra.00867-23 -
Microbiology Resource Announcements May 2024A subgroup of Salmonella (S.) enterica subsp. enterica serovar Paratyphi B is significantly associated with invasive infections in humans. We report the complete genome...
A subgroup of Salmonella (S.) enterica subsp. enterica serovar Paratyphi B is significantly associated with invasive infections in humans. We report the complete genome sequence of a potentially invasive. Paratyphi B isolated from a mute swan () found dead at an urban recreation park in Berlin, Germany.
PubMed: 38809039
DOI: 10.1128/mra.01056-23 -
Microbiology Spectrum May 2024Bacterial genotyping through whole-genome sequencing plays a crucial role in disease surveillance and outbreak investigations in public health laboratories. This study...
UNLABELLED
Bacterial genotyping through whole-genome sequencing plays a crucial role in disease surveillance and outbreak investigations in public health laboratories. This study assessed the effectiveness of Oxford Nanopore Technologies (ONT) sequencing in the genotyping of and serovar Enteritidis. Our results indicated that ONT sequences, generated with the R10.4.1 flow cell and basecalled using the Dorado 0.5.0 Super Accurate 4.3 model, exhibited comparable accuracy to Illumina sequences, effectively discriminating among bacterial strains from outbreaks. These findings suggest that ONT sequencing has the potential to be a promising tool for rapid whole-genome sequencing of bacterial pathogens in public health laboratories for epidemiological investigations.
IMPORTANCE
This study unveils that Oxford Nanopore Technologies sequencing, by itself, holds the potential to serve as a whole-genome sequencing-based genotyping tool in public health laboratories, enabling routine subtyping of bacterial isolates for disease surveillance and outbreak investigations.
PubMed: 38809017
DOI: 10.1128/spectrum.00509-24 -
Microbial Biotechnology Jun 2024Some bacteria, such as Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium), have an inherent ability to locate solid tumours, making them a versatile... (Review)
Review
Some bacteria, such as Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium), have an inherent ability to locate solid tumours, making them a versatile platform that can be combined with other tools to improve the tumour diagnosis and treatment. In anti-cancer therapy, bacteria function by carrying drugs directly or expressing exogenous therapeutic genes. The application of bacterial imaging in tumour diagnosis, a novel and promising research area, can indeed provide dynamic and real-time monitoring in both pre-treatment assessment and post-treatment detection. Different imaging techniques, including optical technology, acoustic imaging, magnetic resonance imaging (MRI) and nuclear medicine imaging, allow us to observe and track tumour-associated bacteria. Optical imaging, including bioluminescence and fluorescence, provides high-sensitivity and high-resolution imaging. Acoustic imaging is a real-time and non-invasive imaging technique with good penetration depth and spatial resolution. MRI provides high spatial resolution and radiation-free imaging. Nuclear medicine imaging, including positron emission tomography (PET) and single photon emission computed tomography (SPECT) can provide information on the distribution and dynamics of bacterial population. Moreover, strategies of synthetic biology modification and nanomaterial engineering modification can improve the viability and localization ability of bacteria while maintaining their autonomy and vitality, thus aiding the visualization of gut bacteria. However, there are some challenges, such as the relatively low bacterial abundance and heterogeneously distribution within the tumour, the high dimensionality of spatial datasets and the limitations of imaging labeling tools. In summary, with the continuous development of imaging technology and nanotechnology, it is expected to further make in-depth study on tumour-associated bacteria and develop new bacterial imaging methods for tumour diagnosis.
Topics: Neoplasms; Humans; Escherichia coli; Bacteria; Salmonella typhimurium; Diagnostic Imaging; Animals; Optical Imaging
PubMed: 38808743
DOI: 10.1111/1751-7915.14474 -
TheScientificWorldJournal 2024The dried stigmas of L. produce saffron, a precious spice used for its culinary and medicinal properties since ancient times, while its petals are considered the main... (Comparative Study)
Comparative Study
The dried stigmas of L. produce saffron, a precious spice used for its culinary and medicinal properties since ancient times, while its petals are considered the main by-product of saffron production. The present study aimed to comparatively evaluate the phenolic content, antioxidant capacity, and antibacterial activity of methanolic extracts of stigmas and petals of L. from Taliouine. The polyphenol content was measured using the Folin-Ciocalteu method, the antioxidant activity was determined using the DPPH free radical scavenging method, and the well-diffusion method was used to assess antibacterial activity against seven pathogenic bacterial strains (, , and ). Furthermore, the minimum inhibitory concentration (MIC) of the extracts was determined using the microdilution broth test. Our findings revealed that stigmas and petals contained phenolic compounds at the rate of 56.11 ± 4.70 and 64.73 ± 3.42 mg GAE/g, as well as DPPH radical scavenging capacity with IC of 1700 g/ml and 430 g/ml, respectively. Petal extract showed more effective antibacterial activity, with inhibition diameters ranging from 10.66 ± 0.57 to 22.00 ± 1.00 mm and MIC values ranging from 2.81 to 5.62 mg/ml, compared to the stigma extract, which displayed inhibition diameters from 10.00 ± 0.00 to 18.67 ± 0.76 mm and MIC from 2.81 to 11.25 mg/ml, against five of the seven bacterial strains tested, including S. aureus, E. coli, P. vulgaris, P. aeruginosa, and . Statistical analyses were performed to determine the significance of these results. Thus, stigmas and petals of L. might serve as a suitable source of natural antioxidant and antimicrobial agents for application in the food and pharmaceutical industries.
Topics: Crocus; Anti-Bacterial Agents; Antioxidants; Plant Extracts; Phenols; Microbial Sensitivity Tests; Flowers; Morocco; Bacteria
PubMed: 38808159
DOI: 10.1155/2024/6676404 -
Scientific Reports May 2024Salmonella enterica is a pathogenic bacterium known for causing severe typhoid fever in humans, making it important to study due to its potential health risks and...
Salmonella enterica is a pathogenic bacterium known for causing severe typhoid fever in humans, making it important to study due to its potential health risks and significant impact on public health. This study provides evolutionary classification of proteins from Salmonella enterica pangenome. We classified 17,238 domains from 13,147 proteins from 79,758 Salmonella enterica strains and studied in detail domains of 272 proteins from 14 characterized Salmonella pathogenicity islands (SPIs). Among SPIs-related proteins, 90 proteins function in the secretion machinery. 41% domains of SPI proteins have no previous sequence annotation. By comparing clinical and environmental isolates, we identified 3682 proteins that are overrepresented in clinical group that we consider as potentially pathogenic. Among domains of potentially pathogenic proteins only 50% domains were annotated by sequence methods previously. Moreover, 36% (1330 out of 3682) of potentially pathogenic proteins cannot be classified into Evolutionary Classification of Protein Domains database (ECOD). Among classified domains of potentially pathogenic proteins the most populated homology groups include helix-turn-helix (HTH), Immunoglobulin-related, and P-loop domains-related. Functional analysis revealed overrepresentation of these protein in biological processes related to viral entry into host cell, antibiotic biosynthesis, DNA metabolism and conformation change, and underrepresentation in translational processes. Analysis of the potentially pathogenic proteins indicates that they form 119 clusters or novel potential pathogenicity islands (NPPIs) within the Salmonella genome, suggesting their potential contribution to the bacterium's virulence. One of the NPPIs revealed significant overrepresentation of potentially pathogenic proteins. Overall, our analysis revealed that identified potentially pathogenic proteins are poorly studied.
Topics: Genomic Islands; Salmonella enterica; Bacterial Proteins; Genome, Bacterial; Humans; Protein Domains
PubMed: 38806511
DOI: 10.1038/s41598-024-60991-x -
Virulence Dec 2024subspecies serovar Typhimurium is an intracellular pathogen that invades and colonizes the intestinal epithelium. Following bacterial invasion, is enclosed within a...
subspecies serovar Typhimurium is an intracellular pathogen that invades and colonizes the intestinal epithelium. Following bacterial invasion, is enclosed within a membrane-bound vacuole known as a -containing vacuole (SCV). However, a subset of has the capability to prematurely rupture the SCV and escape, resulting in hyper-replication within the cytosol of epithelial cells. A recently published RNA-seq study provides an overview of cytosolic and vacuolar upregulated genes and highlights vacuolar upregulation. Here, using transcription kinetics, protein production profile, and immunofluorescence microscopy, we showed that PagN is exclusively produced by in SCV. Gentamicin protection and chloroquine resistance assays were performed to demonstrate that deletion of affects replication by affecting the cytosolic bacterial population. This study presents the first example of a virulence factor expressed within the endocytic compartment, which has a significant impact on the dynamics of cytosolic hyper-replication.
Topics: Salmonella typhimurium; Cytosol; Vacuoles; Bacterial Proteins; Virulence Factors; Humans; Virulence; Salmonella Infections; HeLa Cells; Epithelial Cells; Gene Expression Regulation, Bacterial
PubMed: 38804638
DOI: 10.1080/21505594.2024.2357670 -
Frontiers in Immunology 2024None of the typhoid Vi Polysaccharide (ViPS) subunit vaccines incorporate adjuvants, and the immunogenicity of ViPS vaccines (e.g. Typbar TCV and Typhim Vi) is in part...
None of the typhoid Vi Polysaccharide (ViPS) subunit vaccines incorporate adjuvants, and the immunogenicity of ViPS vaccines (e.g. Typbar TCV and Typhim Vi) is in part due to associated TLR4 ligands such as endotoxin present in these vaccines. Since endotoxin content in vaccines is variable and kept very low due to inherent toxicity, it was hypothesized that incorporating a defined amount of a non-toxic TLR4-ligand such as monophosphoryl lipid A in ViPS vaccines would improve their immunogenicity. To test this hypothesis, a monophosphoryl lipid A-based adjuvant formulation named Turbo was developed. Admixing Turbo with Typbar TCV (ViPS-conjugated to tetanus toxoid) increased the levels of anti-ViPS IgM, IgG1, IgG2b, IgG2a/c, and IgG3 in inbred and outbred mice. In infant mice, a single immunization with Turbo adjuvanted Typbar TCV resulted in a significantly increased and durable IgG response and improved the control of bacterial burden compared to mice immunized without Turbo. Similarly, when adjuvanted with Turbo, the antibody response and control of bacteremia were also improved in mice immunized with Typhim Vi, an unconjugated vaccine. The immunogenicity of unconjugated ViPS is inefficient in young mice and is lost in adult mice when immunostimulatory ligands in ViPS are removed. Nevertheless, when adjuvanted with Turbo, poorly immunogenic ViPS induced a robust IgG response in young and adult mice, and this was observed even under antigen-limiting conditions. These data suggest that incorporation of Turbo as an adjuvant will make typhoid vaccines more immunogenic regardless of their intrinsic immunogenicity or conjugation status and maximize the efficacy across all ages.
Topics: Animals; Typhoid-Paratyphoid Vaccines; Mice; Toll-Like Receptor 4; Vaccines, Subunit; Antibodies, Bacterial; Adjuvants, Immunologic; Lipid A; Typhoid Fever; Immunoglobulin G; Female; Ligands; Polysaccharides, Bacterial; Immunogenicity, Vaccine; Adjuvants, Vaccine; Salmonella typhi; Mice, Inbred BALB C
PubMed: 38799439
DOI: 10.3389/fimmu.2024.1383476