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ACS Applied Materials & Interfaces Apr 2024is one of the most invasive foodborne pathogens that cause listeriosis, making it imperative to explore novel inhibiting strategies for alleviating its infection. The...
is one of the most invasive foodborne pathogens that cause listeriosis, making it imperative to explore novel inhibiting strategies for alleviating its infection. The adhesion and invasion of within host cells are partly orchestrated by an invasin protein internalin A (InlA), which facilitates bacterial passage by interacting with the host cell E-cadherin (E-Cad). Hence, in this work, we proposed an aptamer blocking strategy by binding to the region on InlA that directly mediated E-Cad receptor engagement, thereby alleviating infection. An aptamer GA8 with a robust G-quadruplex (G4) structural feature was designed through truncation and base mutation from the original aptamer A8. The molecular docking and dynamics analysis showed that the InlA/aptamer GA8 binding interface was highly overlapping with the natural InlA/E-Cad binding interface, which confirmed that GA8 can tightly and stably bind InlA and block more distinct epitopes on InlA that involved the interaction with E-Cad. On the cellular level, it was confirmed that GA8 effectively blocked adhesion with an inhibition rate of 78%. Overall, the robust G4 aptamer-mediated design provides a new direction for the development of inhibitors against other wide-ranging and emerging pathogens.
Topics: Humans; Listeria monocytogenes; Molecular Docking Simulation; Listeriosis; Mutation; Bacterial Proteins
PubMed: 38519414
DOI: 10.1021/acsami.4c00496 -
International Journal of Microbiology 2024South Africa recently (2017-18) experienced the largest outbreak of human listeriosis in the world caused by following the consumption of "polony," a ready-to-eat meat...
Detection of Pathogenic Serogroups and Virulence Genes in Strains Isolated from Beef and Beef Products Retailed in Gauteng Province, South Africa, Using Phenotypic and Polymerase Chain Reaction (PCR)-Based Methods.
South Africa recently (2017-18) experienced the largest outbreak of human listeriosis in the world caused by following the consumption of "polony," a ready-to-eat meat product. Most (59%) cases originated from Gauteng province, South Africa. As a follow-up study to the outbreak, we used standard bacteriological and molecular methods to determine the prevalence of pathogenic and virulent serogroups of in various beef and beef products retailed in Gauteng province, South Africa. The overall prevalence of spp. was 28% (112/400), comprising (9.3%), (16.3%), and (2.5%) ( < 0.001). It is crucial to have detected that the region (=0.036), type of product (=0.032), and temperature at storage (=0.011) significantly affected the occurrence of in beef products. It is alarming that pathogenic serogroups 4b-4d-4e (51.4%) and 1/2a-3a (43.2%) were detected among the isolates of . Importantly, they were all carriers of seven virulence-associated genes (). Our study also demonstrated that 16.7% of "polony" samples investigated were contaminated with Considering that pathogenic and virulent contaminated beef and beef products retailed in South Africa, the food safety risk posed to consumers remains and cannot be ignored. Therefore, it is imperative to reduce the contamination of these products with during beef production, processing, and retailing to avoid future outbreaks of human listeriosis in the country.
PubMed: 38510936
DOI: 10.1155/2024/8891963 -
Journal of Medical Microbiology Mar 2024Listeriosis is a foodborne infection in humans caused by Consumption of contaminated food can lead to severe infection in vulnerable patients, that can be fatal....
Listeriosis is a foodborne infection in humans caused by Consumption of contaminated food can lead to severe infection in vulnerable patients, that can be fatal. Clinical manifestations include sepsis and meningitis, and in pregnancy-associated infection, miscarriage and stillbirth. Diagnosis is confirmed by culture and identification of the pathogen from blood, cerebrospinal fluid, vaginal swab, placenta or amniotic fluid. Treatment regimens recommend amoxicillin, ampicillin or an aminoglycoside. Virulence factors mediate bacterial adhesion and invasion of gut epithelial cells. Other factors mediate biofilm formation and tolerance to low temperatures and high salt concentrations facilitating persistence and survival in the environment.
Topics: Pregnancy; Female; Humans; Listeria monocytogenes; Listeriosis; Ampicillin; Pregnancy Complications, Infectious; Anti-Bacterial Agents; Food Microbiology
PubMed: 38506266
DOI: 10.1099/jmm.0.001800 -
European Journal of Immunology May 2024Resident memory T (T) cells have been recently established as an important subset of memory T cells that provide early and essential protection against reinfection in...
Resident memory T (T) cells have been recently established as an important subset of memory T cells that provide early and essential protection against reinfection in the absence of circulating memory T cells. Recent findings showing that T expand in vivo after repeated antigenic stimulation indicate that these memory T cells are not terminally differentiated. This suggests an opportunity for in vitro T expansion to apply in an immunotherapy setting. However, it has also been shown that T may not maintain their identity and form circulating memory T cells after in vivo restimulation. Therefore, we set out to determine how T respond to antigenic activation in culture. Using Listeria monocytogenes and LCMV infection models, we found that T from the intraepithelial compartment of the small intestine expand in vitro after antigenic stimulation and subsequent resting in homeostatic cytokines. A large fraction of the expanded T retained their phenotype, including the expression of key T markers CD69 and CD103 (ITGAE). The optimal culture of T required low O pressure to maintain the expression of these and other T-associated molecules. Expanded T retained their effector capacity to produce cytokines after restimulation, but did not acquire a highly glycolytic profile indicative of effector T cells. The proteomic analysis confirmed T profile retention, including expression of T-related transcription factors, tissue retention factors, adhesion molecules, and enzymes involved in fatty acid metabolism. Collectively, our data indicate that limiting oxygen conditions supports in vitro expansion of T cells that maintain their T phenotype, at least in part, suggesting an opportunity for therapeutic strategies that require in vitro expansion of T.
Topics: Animals; Memory T Cells; Immunologic Memory; Mice; Listeria monocytogenes; Antigens, CD; Integrin alpha Chains; Mice, Inbred C57BL; Listeriosis; Lectins, C-Type; Antigens, Differentiation, T-Lymphocyte; Cytokines; Lymphocyte Activation; Lymphocytic choriomeningitis virus; Intestinal Mucosa; CD8-Positive T-Lymphocytes; Intestine, Small; Cells, Cultured
PubMed: 38501878
DOI: 10.1002/eji.202350873 -
The Neuroradiology Journal Mar 2024Listeriosis has more than a 50% mortality when the central nervous system is involved, necessitating rapid diagnosis and treatment. We present four patients with brain...
Listeriosis has more than a 50% mortality when the central nervous system is involved, necessitating rapid diagnosis and treatment. We present four patients with brain abscesses in the setting of diagnosed neurolisteriosis, all of which demonstrated an odd presentation of multiple small, contiguous tubular lesions with rim enhancement on magnetic resonance imaging. Our review of published cases of neurolisteriosis suggests that this may be a useful pattern to identify neurolisteriosis abscesses, allowing earlier detection and therapy.
PubMed: 38494758
DOI: 10.1177/19714009241240054 -
The Veterinary Record Mar 2024
Topics: Animals; Sheep; Female; Listeriosis; Animal Husbandry; Sheep Diseases
PubMed: 38488587
DOI: 10.1002/vetr.4067 -
Journal of Infection and Public Health Apr 2024Food-borne pathogen Listeria monocytogenes is abundantly present in nature and accountable for sporadic and epidemic cases of listeriosis in humans. The objective of...
BACKGROUND
Food-borne pathogen Listeria monocytogenes is abundantly present in nature and accountable for sporadic and epidemic cases of listeriosis in humans. The objective of this study was to screen common food sources for L. monocytogenes using biochemical and molecular methods to detect and characterise its toxin genes as well as for biofilm formation.
METHODS
A total of 92 samples, comprising dairy and street food products, were randomly collected from various sources for this investigation. The collected samples were processed for biochemical and molecular methods to detect L. monocytogenes. Additionally, virulence factors associated genes, antibiogram profiles and biofilm formation related assays were determined.
RESULTS
L. monocytogenes presence was confirmed using molecular detection methods targeting prs and lmo1030 genes, along with MALDI-TOF MS. Following 16 S rRNA sequencing, the identified Listeria species were further categorised into two groups. L. monocytogenes was detected in two (2.17%) food samples tested (L-23 and L-74). Multiplex PCR indicated the presence of seven virulence-related genes in L. monocytogenes isolates, i.e., inlA, inlB, prfA, iap, actA, plcB, and hlyA. In addition, 17 antibiotics were tested, whereby two isolates showed resistance to clindamycin and azithromycin, while one isolate (L-74) was also resistant to nalidixic acid, co-trimoxazole, ampicillin, norfloxacin, and cefotaxime. L-23 and L-74 isolates showed biofilm formation, especially at pH 8.6 and 37°C.
CONCLUSIONS
Besides the demonstration of the presence of L. monocytogenes in some dairy and street food products, this study underscores the need to increase the standards of hygiene on the one hand and the importance of the surveillance of food-borne pathogens on the other.
Topics: Humans; Listeria monocytogenes; India; Listeriosis; Anti-Bacterial Agents; Virulence Factors; Food Microbiology
PubMed: 38479066
DOI: 10.1016/j.jiph.2024.02.014 -
Foods (Basel, Switzerland) Feb 2024Better knowledge regarding the dose-response (DR) model is needed to refine the assessment of the risk of foodborne listeriosis. In 2018, the European Food Safety...
Better knowledge regarding the dose-response (DR) model is needed to refine the assessment of the risk of foodborne listeriosis. In 2018, the European Food Safety Agency (EFSA) derived a lognormal Poisson DR model for 14 different age-sex sub-groups, marginally to strain virulence. In the present study, new sets of parameters are developed by integrating the EFSA model for these sub-groups together with three classes of strain virulence characteristics ("less virulent", "virulent", and "more virulent"). Considering classes of virulence leads to estimated relative risks (RRs) of listeriosis following the ingestion of 1000 bacteria of "less virulent" vs. "more virulent" strains ranging from 21.6 to 24.1, depending on the sub-group. These relatively low RRs when compared with RRs linked to comorbidities described in the literature suggest that the influence of comorbidity on the occurrence of invasive listeriosis for a given exposure is much more important than the influence of the virulence of the strains. The updated model parameters allow better prediction of the risk of invasive listeriosis across a population of interest, provided the necessary data on population demographics and the proportional contribution of strain virulence classes in food products of interest are available. An R package is made available to facilitate the use of these dose-response models.
PubMed: 38472864
DOI: 10.3390/foods13050751 -
Foods (Basel, Switzerland) Feb 2024is a foodborne pathogen that causes listeriosis, a group of human illnesses that appear more frequently in countries with better-developed food supply systems. This... (Review)
Review
is a foodborne pathogen that causes listeriosis, a group of human illnesses that appear more frequently in countries with better-developed food supply systems. This review discusses the efficacy of actual biocontrol methods combined with the main types of food involved in illnesses. Comments on bacteriophages, lactic acid bacteria, bacteriocins, essential oils, and endolysins and derivatives, as main biological antilisterial agents, are made bearing in mind that, using them, food processors can intervene to protect consumers. Both commercially available antilisterial products and solutions presented in scientific papers for mitigating the risk of contamination are emphasized. Potential combinations between different types of antilisterial agents are highlighted for their synergic effects (bacteriocins and essential oils, phages and bacteriocins, lactic acid bacteria with natural or synthetic preservatives, etc.). The possibility to use various antilisterial biological agents in active packaging is also presented to reveal the diversity of means that food processors may adopt to assure the safety of their products. Integrating biocontrol solutions into food processing practices can proactively prevent outbreaks and reduce the occurrences of -related illnesses.
PubMed: 38472848
DOI: 10.3390/foods13050734 -
Foods (Basel, Switzerland) Feb 2024Invasive listeriosis, due to its severe nature in susceptible populations, has been the focus of many quantitative risk assessment (QRA) models aiming to provide a... (Review)
Review
Invasive listeriosis, due to its severe nature in susceptible populations, has been the focus of many quantitative risk assessment (QRA) models aiming to provide a valuable guide in future risk management efforts. A review of the published QRA models of in seafood was performed, with the objective of appraising the effectiveness of the control strategies at different points along the food chain. It is worth noting, however, that the outcomes of a QRA model are context-specific, and influenced by the country and target population, the assumptions that are employed, and the model architecture itself. Studies containing QRA models were retrieved through a literature search using properly connected keywords on Scopus and PubMed. All 13 QRA models that were recovered were of short scope, covering, at most, the period from the end of processing to consumption; the majority (85%) focused on smoked or gravad fish. Since the modelled pathways commenced with the packaged product, none of the QRA models addressed cross-contamination events. Many models agreed that keeping the product's temperature at 4.0-4.5 °C leads to greater reductions in the final risk of listeriosis than reducing the shelf life by one week and that the effectiveness of both measures can be surpassed by reducing the initial occurrence of in the product (at the end of processing). It is, therefore, necessary that future QRA models for RTE seafood contain a processing module that can provide insight into intervention strategies that can retard ' growth, such as the use of bacteriocins, ad hoc starter cultures and/or organic acids, and other strategies seeking to reduce cross-contamination at the facilities, such as stringent controls for sanitation procedures. Since risk estimates were shown to be moderately driven by growth kinetic parameters, namely, the exponential growth rate, the minimum temperature for growth, and the maximum population density, further work is needed to reduce uncertainties.
PubMed: 38472829
DOI: 10.3390/foods13050716