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British Journal of Hospital Medicine... May 2024We present an unusual case of rhomboencephalitis in a young, healthy patient. Although meningitis is usually associated with immunodeficiency, rhomboencephalitis is...
We present an unusual case of rhomboencephalitis in a young, healthy patient. Although meningitis is usually associated with immunodeficiency, rhomboencephalitis is more commonly seen in immunocompetent patients. The wide differential for rhomboencephalitis can create a diagnostic challenge. Without prompt pathogen identification and appropriate antibiotic regimen, central nervous system infections can be fatal. Cerebro-Spinal Fluid (CSF) Polymerase Chain Reaction (PCR) aided a prompt diagnosis and adjustment of therapy to achieve a good patient outcome.
Topics: Humans; Listeria monocytogenes; Immunocompetence; Listeriosis; Anti-Bacterial Agents; Male; Rhombencephalon; Magnetic Resonance Imaging; Meningitis, Listeria; Adult; Encephalitis; Polymerase Chain Reaction
PubMed: 38815971
DOI: 10.12968/hmed.2023.0453 -
Frontiers in Bioscience (Landmark... May 2024, a Gram-positive bacterium, is a prominent foodborne pathogen that causes listeriosis and poses substantial health hazards worldwide. The continuing risk of listeriosis...
BACKGROUND
, a Gram-positive bacterium, is a prominent foodborne pathogen that causes listeriosis and poses substantial health hazards worldwide. The continuing risk of listeriosis outbreaks underlies the importance of designing an effective prevention strategy and developing a robust immune response by reverse vaccinology approaches. This study aimed to provide a critical approach for developing a potent multiepitope vaccine against this foodborne disease.
METHODS
A chimeric peptide construct containing 5 B-cell epitopes, 16 major histocompatibility complex I (MHC-I) epitopes, and 18 MHC-II epitopes were used to create a subunit vaccination against . The vaccine safety was evaluated by several online methods, and molecular docking was performed using ClusPro to determine the binding affinity. Immune simulation was performed using the C-ImmSimm server to demonstrate the immune response.
RESULTS
The results validated the antigenicity, non-allergenicity, and nontoxicity of the chimeric peptide construct, confirming its suitability as a subunit vaccine. Molecular docking showed a good score of 1276.5 and molecular dynamics simulations confirmed the construct's efficacy, demonstrating its promise as a good candidate for listeriosis prophylaxis. The population coverage was as high as 91.04% with a good immune response, indicating good antigen presentation with dendritic cells and production of memory cells.
CONCLUSIONS
The findings of this study highlight the potential of the designed chimeric peptide construct as an effective subunit vaccine against , paving the way for future advances in preventive methods and vaccine design.
Topics: Listeria monocytogenes; Molecular Docking Simulation; Bacterial Vaccines; Vaccines, Subunit; Listeriosis; Computational Biology; Epitopes, B-Lymphocyte; Humans; Epitopes; Molecular Dynamics Simulation; Animals; Foodborne Diseases; Immunoinformatics
PubMed: 38812301
DOI: 10.31083/j.fbl2905176 -
Scientific Reports May 2024Current knowledge about effects of disturbance on the fate of invaders in complex microbial ecosystems is still in its infancy. In order to investigate this issue, we...
Current knowledge about effects of disturbance on the fate of invaders in complex microbial ecosystems is still in its infancy. In order to investigate this issue, we compared the fate of Klebsiella pneumoniae (Kp) and Listeria monocytogenes (Lm) in soil microcosms. We then used environmental disturbances (freeze-thaw or heat cycles) to compare the fate of both invaders and manipulate soil microbial diversity. Population dynamics of the two pathogens was assessed over 50 days of invasion while microbial diversity was measured at times 0, 20 and 40 days. The outcome of invasion was strain-dependent and the response of the two invaders to disturbance differed. Resistance to Kp invasion was higher under the conditions where resident microbial diversity was the highest while a significant drop of diversity was linked to a higher persistence. In contrast, Lm faced stronger resistance to invasion in heat-treated microcosms where diversity was the lowest. Our results show that diversity is not a universal proxy of resistance to microbial invasion, indicating the need to properly assess other intrinsic properties of the invader, such as its metabolic repertoire, or the array of interactions between the invader and resident communities.
Topics: Soil Microbiology; Listeria monocytogenes; Humans; Microbiota; Klebsiella pneumoniae; Temperature; Biodiversity
PubMed: 38811807
DOI: 10.1038/s41598-024-63284-5 -
Science Advances May 2024Infusion of C-labeled metabolites provides a gold standard for understanding the metabolic processes used by T cells during immune responses in vivo. Through infusion of...
Infusion of C-labeled metabolites provides a gold standard for understanding the metabolic processes used by T cells during immune responses in vivo. Through infusion of C-labeled metabolites (glucose, glutamine, and acetate) in -infected mice, we demonstrate that CD8 T effector (Teff) cells use metabolites for specific pathways during specific phases of activation. Highly proliferative early Teff cells in vivo shunt glucose primarily toward nucleotide synthesis and leverage glutamine anaplerosis in the tricarboxylic acid (TCA) cycle to support adenosine triphosphate and de novo pyrimidine synthesis. In addition, early Teff cells rely on glutamic-oxaloacetic transaminase 1 (Got1)-which regulates de novo aspartate synthesis-for effector cell expansion in vivo. CD8 Teff cells change fuel preference over the course of infection, switching from glutamine- to acetate-dependent TCA cycle metabolism late in infection. This study provides insights into the dynamics of Teff metabolism, illuminating distinct pathways of fuel consumption associated with CD8 Teff cell function in vivo.
Topics: Glutamine; Animals; CD8-Positive T-Lymphocytes; Acetates; Mice; Carbon Isotopes; Listeriosis; Listeria monocytogenes; Citric Acid Cycle; Glucose; Mice, Inbred C57BL
PubMed: 38809979
DOI: 10.1126/sciadv.adj1431 -
MBio May 2024Pathogenic bacteria rely on secreted virulence factors to cause disease in susceptible hosts. However, in Gram-positive bacteria, the mechanisms underlying secreted...
UNLABELLED
Pathogenic bacteria rely on secreted virulence factors to cause disease in susceptible hosts. However, in Gram-positive bacteria, the mechanisms underlying secreted protein activation and regulation post-membrane translocation remain largely unknown. Using proteomics, we identified several proteins that are dependent on the secreted chaperone PrsA2. We followed with phenotypic, biochemical, and biophysical assays and computational analyses to examine the regulation of a detected key secreted virulence factor, listeriolysin O (LLO), and its interaction with PrsA2 from the bacterial pathogen (). Critical to virulence is internalization by host cells and the subsequent action of the cholesterol-dependent pore-forming toxin, LLO, which enables bacterial escape from the host cell phagosome. Since is a Gram-positive organism, the space between the cell membrane and wall is solvent exposed. Therefore, we hypothesized that the drop from neutral to acidic pH as the pathogen is internalized into a phagosome is critical to regulating the interaction of PrsA2 with LLO. Here, we demonstrate that PrsA2 directly interacts with LLO in a pH-dependent manner. We show that PrsA2 protects and sequesters LLO under neutral pH conditions where LLO can be observed to aggregate. In addition, we identify molecular features of PrsA2 that are required for interaction and ultimately the folding and activity of LLO. Moreover, protein-complex modeling suggests that PrsA2 interacts with LLO via its cholesterol-binding domain. These findings highlight a mechanism by which a Gram-positive secretion chaperone regulates the secretion, stability, and folding of a pore-forming toxin under conditions relevant to host cell infection.
IMPORTANCE
is a ubiquitous food-borne pathogen that can cause severe disease to vulnerable populations. During infection, relies on a wide repertoire of secreted virulence factors including the LLO that enables the bacterium to invade the host and spread from cell to cell. After membrane translocation, secreted factors must become active in the challenging bacterial cell membrane-wall interface. However, the mechanisms required for secreted protein folding and function are largely unknown. encodes a chaperone, PrsA2, that is critical for the activity of secreted factors. Here, we show that PrsA2 directly associates and protects the major virulence factor, LLO, under conditions corresponding to the host cytosol, where LLO undergoes irreversible denaturation. Additionally, we identify molecular features of PrsA2 that enable its interaction with LLO. Together, our results suggest that and perhaps other Gram-positive bacteria utilize secreted chaperones to regulate the activity of pore-forming toxins during infection.
PubMed: 38809022
DOI: 10.1128/mbio.00743-24 -
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 -
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 -
Fitoterapia Jul 2024Thymus daenensis Celak (Lamiaceae family), known as denaian thyme, is an Iranian endemic plant, commonly used for its carminative, expectorant, antibacterial and...
Validation of the traditional antimicrobial use of the Iranian medicinal plant Thymus daenensis Celak through phytochemical characterization of its bioactive constituents.
Thymus daenensis Celak (Lamiaceae family), known as denaian thyme, is an Iranian endemic plant, commonly used for its carminative, expectorant, antibacterial and antifungal properties. Previous studies report the chemical profile of the essential oil of T. daenensis aerial parts, but little is known about its non volatile constituents. Herein, phytochemical and biological investigation of the polar extract of T. daenensis aerial parts to provide further insight into traditional use of this plant has been accomplished. High-performance liquid chromatography coupled to linear ion-trap and orbitrap high-resolution mass spectrometry (LC-ESI/LTQOrbitrap/MS/MS) analysis of MeOH extract was performed to guide the isolation of specialized metabolites and successive characterization by NMR analysis. MeOH extract displayed antioxidant activity evaluated by DPPH (EC = 48.99 ± 1.47 μg/mL) and TEAC assay (1.37 mg/mL). Successively, the biofilm inhibitory activity of extract and isolated compounds against mature biofilms of Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Listeria monocytogenes, and Staphylococcus aureus, and their influence on the metabolism of sessile bacterial cells were evaluated. Two previously unreported thymol derivatives have been identified. The biofilm inhibitory activity of isolated compounds highlighted a promising antimicrobial action for the tested compounds. In particular, vanillic acid, (3S,5R,6R,7E,9S)-megastigm-7-ene-3,5,6,9-tetrol 3-O-β-D-glucopyranoside, thymoquinol-2-O-β-D-glucopyranoside and the never reported compound daenol resulted capable of exerting inhibitory activity vs all pathogenic strains. All compounds tested at a concentration of 10 μg/mL inhibited the metabolism of the sessile cells of E. coli at a percentage ranging between 37.7% and 77.39%, and of L.monocytogenes at a percentage ranging between 21.79% and 71.17%.
Topics: Thymus Plant; Phytochemicals; Iran; Plant Extracts; Antioxidants; Plant Components, Aerial; Biofilms; Plants, Medicinal; Anti-Bacterial Agents; Molecular Structure; Microbial Sensitivity Tests
PubMed: 38801898
DOI: 10.1016/j.fitote.2024.106042 -
Veterinary World Apr 2024Stingless bees are generally found in tropical countries, including Indonesia. In West Sumatra, stingless bees are known as , consist of several species with different...
BACKGROUND AND AIM
Stingless bees are generally found in tropical countries, including Indonesia. In West Sumatra, stingless bees are known as , consist of several species with different characteristics; however, the properties of honey produced by stingless bees have not yet been explored. This study aimed to determine the physicochemical, antioxidant, and antimicrobial activities as well as the microbiota profile of stingless bee honey from the bee species , , , and that are intensively developed in West Sumatra, Indonesia.
MATERIALS AND METHODS
Honey produced by the stingless bee species , . , , and originating in West Sumatra was examined in the present study. The physicochemical properties (Association of Official Analytical Chemists), antioxidant activity (2,2-diphenyl-1-picrylhydrazyl technique), total phenols (Folin-Ciocalteu method), antimicrobial activity (Agar-Well diffusion test), total lactic acid bacteria, and microbiota diversity were measured in stingless bee honey samples.
RESULTS
Stingless bee species significantly affected the physicochemical properties, antioxidant activity, total phenolic content, antimicrobial activity, and total lactic acid bacteria (p = 0.05), except for the crude fiber content. The carbohydrate profiles of honey produced by and were dominated by monosaccharides, whereas those of honey from and were dominated by disaccharides. In terms of antioxidant activity (half maximal inhibitory concentration [IC] value), there were no significant differences (p > 0.05) between honey from , , and , but there were significant differences (p > 0.05) between honey from . The honey of and had the highest total phenolic content (65.65 ± 14.00 and 69.78 ± 8.06, respectively). In addition, honey from the four stingless bee species showed antimicrobial activity against the pathogenic bacteria , , , and . From the principal co-ordinate analysis (PCoA) results, it can be concluded that the microbiota profiles of the four stingless bee honey samples differed.
CONCLUSION
The results showed that honey from , , , and has different physicochemical characteristics, antioxidant activity, antimicrobial activity, and microbiota diversity. By knowing the content of this stingless bee honey, the results of this study can be used as information that this stingless bee honey has the potential as a functional food that is beneficial for health.
PubMed: 38798299
DOI: 10.14202/vetworld.2024.785-795 -
Veterinary World Apr 2024Donkey and mare milk have high nutritional and functional values, but their lactic acid bacteria (LAB) content remains poorly studied and undervalued in the Algerian...
Isolation of 60 strains from fermented milk of mares and donkeys in Algeria and identification by 16S rRNA sequencing of lactobacilli: Assessment of probiotic skills of important strains and aromatic productivity power.
BACKGROUND AND AIM
Donkey and mare milk have high nutritional and functional values, but their lactic acid bacteria (LAB) content remains poorly studied and undervalued in the Algerian dairy industry. This study aimed to isolate and select LAB strains that produce antimicrobial substances during fermentation and to characterize the probiotic profiles of each extracted strain to indicate their potential for antioxidant and proteolytic activity.
MATERIALS AND METHODS
This study focuses on isolating and identifying lactic acid bacterial strains from 10 Equid-fermented milk samples collected in two regions of El Bayed Wilaya (Algeria). Identification of LAB strains was obtained by 16S rRNA sequencing. The probiotic properties of important strains and their aromatic productivity power are assessed. To evaluate their antibacterial activity against , , , and , we selected 21 strains. Different induction methods have been used to amplify the antibacterial effects against these pathogenic strains.
RESULTS
Among a total of 60 identified strains, 31 had a probiotic profile, and most were catalase-negative. Aromatic productivity power was observed in eight strains: , , , , , , , and sp1.
CONCLUSION
Our results provide insight into the considerable diversity of LAB present in fermented donkey and mare milk. To meet the expectations of the Algerian dairy industry, it is important that the probiotic skills of the nine selected strains are met. In addition, a significant number of these strains may have important probiotic activity and biotechnological potential.
PubMed: 38798294
DOI: 10.14202/vetworld.2024.829-841