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Listeria monocytogenes is a bacterial pathogen that can cause life-threatening central nervous system (CNS) infections. While mechanisms by which L. monocytogenes and other pathogens traffic to the brain have been studied, a quantitative understanding of the underlying dynamics of colonization and replication within the brain is still lacking. In this study, we used barcoded L. monocytogenes to quantify the bottlenecks and dissemination patterns that lead to cerebral infection. Following intravenous (IV) inoculation, multiple independent invasion events seeded all parts of the CNS from the blood, however, only one clone usually became dominant in the brain. Sequential IV inoculations and intracranial inoculations suggested that clones that had a temporal advantage (i.e., seeded the CNS first), rather than a spatial advantage (i.e., invaded a particular brain region), were the main drivers of clonal dominance. In a foodborne model of cerebral infection with immunocompromised mice, rare invasion events instead led to a highly infected yet monoclonal CNS. This restrictive bottleneck likely arose from pathogen transit into the blood, rather than directly from the blood to the brain. Collectively, our findings provide a detailed quantitative understanding of the L. monocytogenes population dynamics that lead to CNS infection and a framework for studying the dynamics of other cerebral infections.

Listeria monocytogenes (Lm) is a Gram-positive facultative intracellular pathogen that leads a biphasic lifecycle, transitioning its metabolism and selectively inducing virulence genes when it encounters mammalian hosts. Virulence gene expression is controlled by the master virulence regulator PrfA, which is allosterically activated by the host- and bacterially derived glutathione (GSH). The amino acid cysteine is the rate-limiting substrate for GSH synthesis in bacteria and is essential for bacterial growth. Unlike many bacteria, Lm is auxotrophic for cysteine and must import exogenous cysteine for growth and virulence. GSH is enriched in the host cytoplasm, and previous work suggests that Lm utilizes exogenous GSH for PrfA activation. Despite these observations, the import mechanism(s) for GSH remains elusive. Analysis of known GSH importers predicted a homologous importer in Lm comprised of the Ctp ABC transporter and the OppDF ATPases of the Opp oligopeptide importer. Here, we demonstrated that the Ctp complex is a high-affinity GSH/GSSG importer that is required for Lm growth at physiologically relevant concentrations. Furthermore, we demonstrated that OppDF is required for GSH/GSSG import in an Opp-independent manner. These data support a model where Ctp and OppDF form a unique complex for GSH/GSSG import that supports growth and pathogenesis. In addition, we show that Lm utilizes the inorganic sulfur sources thiosulfate and H2S for growth in a CysK-dependent manner in the absence of other cysteine sources. These findings suggest a pathoadaptive role for partial cysteine auxotrophy in Lm, where locally high GSH/GSSG or inorganic sulfur concentrations may signal arrival to distinct host niches.

Listeria monocytogenes, a food-borne pathogen capable of releasing biomarker 3-hydroxy-2-butanone (3H-2B), generally causes a serious threat to human health. Developing 3H-2B gas sensor with excellent performance is of great significance in the diagnosis and prevention of Listeria. Here, we have successfully fabricated Co-doped ZnO nanofibers gas sensor via an electrospinning method, which can be well used for real-time monitoring of Listeria. The results show that the Co-doped ZnO nanofibers have a wurtzite crystal structure and a nanofiber-like morphology with a diameter of 62 nm. The band gap (3.15 eV) of the Co-doped ZnO is significantly narrower than that of the pure ZnO (3.25 eV). The response (168) of the 0.5%Co-doped ZnO based sensor to 100 ppm 3H-2B at 305 °C is 5.37 times greater than that of the pure ZnO (31.3), with a high selectivity, a lower detection limit (100 ppb) and a short response time of 1 s. The enhanced gas sensing mechanism is ascribed to the depletion layer on the ZnO surface, a superposition effect of interface barrier, and the narrowed band gap of the ZnO. [Display omitted] [ABSTRACT FROM AUTHOR]

Foodborne pathogens can easily contaminate chicken meat due to its high nutritional content, and these pathogens can infect humans. One of the most important pathogens contaminating chicken meat and causing severe public health problems is Listeria monocytogenes, which would be responsible for Listeriosis. Therefore, rapid and sensitive detection of L. monocytogenes in chicken meat samples is of great significance. In the current study, the presence of L. monocytogenes in chicken meat samples collected from several markets in Erzurum was detected by comparing two different DNA isolation methods with the Real-time PCR. As a result of the analyses, it was determined that 34% of the chicken meat samples collected were positive for L. monocytogenes in both two methods. According to the comparison analyses of the Bland-Altman method, no significant difference was found between the thermal lysis method and the DNA isolation method by commercial kit. As a result of this study, it has been shown that the thermal lysis method can be successfully applied for the detection of foodborne pathogens in chicken meat when evaluated in terms of workload and cost. The current study is the first report on the comparison of thermal lysis method and DNA isolation by commercial kit in the detection of L. monocytogenes from chicken meat by Real-time PCR. [ABSTRACT FROM AUTHOR]

Based on a systematic review of convolutional neural networks (CNN), this study explores the efficacy of small imaging sensors in monitoring the real-time presence of cyanotoxins and hazardous contaminants in urban ecosystems. To develop a machine learning-based CNN, this study first investigated the relationships between the prevalence of hazardous algal blooms (HABs) and faecal indicator bacteria (FIB) in waterways and aquifers of certain semi-arid zones of Sri Lanka, Sweden and New York (United States). By incorporating a popularly known AbspectroscoPY framework to effectively process the spectrophotometric data of the obtained samples, the formulation subsequently reveals strong positive correlations between FIB coliforms and nutrient loads (particularly nitrate and phosphate). A corroborative association with the incidence of chronic kidney disease of uncertain aetiology (CKDu) among the residents of the studied regions further affirms the reliability of the methodology. These findings underline the need for policymakers to consider the geographical and land-use traits of urban habitats in strategies aimed at reducing water-borne health hazards. [ABSTRACT FROM AUTHOR]

Summary Multiple myeloma (MM), one of the most frequent haematological malignancies, significantly increases the risk of bacterial infections due to treatment‐related side effects, comorbidities and cancer‐induced immune deficiencies. Recently, CD71+ erythroid cells (CECs) have been identified as key immunomodulators in neonates and cancer patients, but their role in MM progression remains unclear. Using a murine MM model, closely resembling human disease, we observed that MM progression is associated with anaemia and an increase in immature CECs, which are characterized by elevated arginase 2 (ARG2) expression. These MM‐associated CECs suppress T‐cell proliferation, contributing to impaired immune responses. Notably, ARG2 deficiency in mice led to slower MM progression and improved survival. Furthermore, MM‐bearing mice exhibited higher susceptibility to Listeria monocytogenes infections, mirroring the increased infection risk in MM patients. Our findings suggest that ARG2‐expressing CECs play a critical role in MM‐associated immune suppression and infection susceptibility, pointing out ARG2 as a potential therapeutic target to enhance immune function and reduce infection risks in MM patients. [ABSTRACT FROM AUTHOR]

In this study, for the first time, the volatile fraction from two domesticated Capsicum annuum accessions ("Paprika" and "Baklouti") collected in Tunisia was investigated by two complementary analytical techniques, such as Solid-Phase Microextraction–Gas Chromatography/Mass Spectrometry (SPME-GC/MS) and Proton Transfer Reaction–Time-of-Flight–Mass Spectrometry (PTR-ToF-MS). The obtained results highlighted the presence of a high number of Volatile Organic Compounds (VOCs), including monoterpene and sesquiterpene compounds with α-curcumene, I-zingiberene, β-bisabolene and β-sesquiphellandrene as the major components. In addition, GC/MS was used to investigate the non-volatile chemical composition of the dried powders and their extracts, which were found to be rich in sulfur compounds, fatty acids and sugars. Eleven bacterial strains were chosen to assess the antimicrobial effectiveness of the extracts. The results showed that the extracts exhibited strain-dependent behavior, and the type strains displayed a greater susceptibility to the treatments, if compared to the wild strains, and, in particular, showed the best antimicrobial activity against Gram-positive bacteria, such as Listeria monocytogenes and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Listeriamonocytogenes (L. monocytogenes) is a prevalent food-borne pathogen that can cause listeriosis, which manifests as meningitis and other symptoms, potentially leading to fatal outcomes in severe cases. In this study, we developed an aptasensor utilizing carboxylated magnetic beads and Cas12a to detect L. monocytogenes. In the absence of L. monocytogenes, the aptamer maintains its spatial configuration, keeping the double-stranded DNA attached and preventing the release of a startup template and activation of Cas12a's trans-cleavage capability. Conversely, in the presence of L. monocytogenes, the aptamer undergoes a conformational change, releasing the double-stranded DNA to serve as a startup template, thereby activating the trans-cleavage capability of Cas12a. Consequently, as the concentration of L. monocytogenes increases, the observable brightness in a blue light gel cutter intensifies, leading to a rise in fluorescence intensity difference compared to the control. This Cas12a aptasensor demonstrates excellent sensitivity towards L. monocytogenes, with a lowest detection limit (LOD) of 57.15 CFU/mL and a linear range of 4×102 to 4×107 CFU/mL (R2=0.9858). Notably, the proposed Cas12a aptasensor exhibited outstanding selectivity and recovery in beef samples, and could be employed for precise monitoring. This Cas12a aptasensor not only provides a novel fluorescent and visual rapid detection method for L. monocytogenes but also offers simplicity, speed, and stability compared to previous detection methods. Furthermore, it is suitable for on-site detection of beef samples. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes biofilm contamination on food contact surfaces is a major concern for the food industry. Nanoparticle encapsulation appears as a novel strategy for food surface disinfection to prevent biofilm formation. Chitosan nanoparticles loaded with nisin and DNase I (DNase-CS-N) have been constructed to exhibit antimicrobial activity against L. monocytogenes. This study aimed to investigate their ability to inhibit L. monocytogenes biofilm formation and eliminate preformed biofilms on food contact surfaces (polystyrene, polyurethane, and stainless steel). DNase-CS-N could decrease 99% and 99.5% biofilm cell numbers at 1/2 MIC and MIC, respectively. At sub-MICs, DNase-CS-N could reduce cell motility (swimming and swarming) and slime production of L. monocytogenes. In terms of effect on biofilm elimination, DNase-CS-N at the concentration of 4 MIC led to 3–4 log reduction in biofilm cells in preformed biofilms, performing higher efficiency compared with other treatments (CSNPs, CS-N). Furthermore, the three-dimensional structure of L. monocytogenes biofilms was severely disrupted after DNase-CS-N treatment, with bacterial cells scattered on the surface. The morphology of biofilm cells was also greatly damaged with wrinkled surfaces, disrupted cell membranes, and leakage of intracellular nucleic acids and proteins. These results indicate the potential applicability of DNase-CS-N for inhibiting and eliminating L. monocytogenes biofilms on food contact surfaces. [ABSTRACT FROM AUTHOR]

Agricultural water is commonly treated with chlorine-based disinfectants, which are impacted by water quality. Understanding how water quality influences disinfectants such as chlorine dioxide (ClO2) against pathogenic bacteria is important for creating efficacious sanitation regimens. In this study, the minimum inhibitory concentration (MIC) of ClO2 needed to achieve a 3-Log reduction against Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes was compared across agricultural water samples. Sterile ddH2O served as a control to compare with environmental samples from Salinas Valley, CA, and laboratory standards. To test different dosages and water qualities, stock ClO2 was diluted in 24-well plates with target concentrations of 10, 5, 2.5, and 1.25 mg/L. Well plates were inoculated with pathogens and treated with sanitizer for 5 min. Following treatment, surviving pathogens were enumerated using viable cell counts. The results demonstrate that groundwater samples had the highest water quality of the environmental samples and required the lowest concentration of disinfectant to achieve 3-Log reduction against both bacteria, with MIC between 1.4 and 2.0 mg/L. Open-source samples had lower water quality and required a higher concentration of ClO2 for 3-Log reduction, with MIC between 2.8 and 5.8 mg/L for both pathogens. There was no correlation between pH, turbidity, or conductivity/TDS and reduction for either STEC or L. monocytogenes , suggesting no individual water metric was driving reduction. A lower dosage was required to achieve 3-Log reduction against STEC, while L. monocytogenes required greater concentrations to achieve the same level of reduction. Overall, these results help guide growers in using ClO2 as a broad-spectrum disinfectant and demonstrate its efficacy in reaching 3-Log reduction across agricultural water samples. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes (LM) is a zoonotic pathogen that causes sporadic infectious listeriosis, which is a foodborne disease associated with consumption of contaminated food or feed. The internal organs of an African lion from a zoo in Shanghai were analysed to determine the cause of death. LM infection was suspected on the basis of the clinical symptoms and pathological changes and confirmed by polymerase chain reaction, whole genome sequencing and phylogenetic analysis. This is the first report of LM infection of an African lion in China. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is ubiquitous in nature and persistent in food‐processing facilities, farms, retail stores, and home and restaurant kitchens. Current research suggests ready‐to‐eat (RTE) products (including RTE hummus and fresh produce) to be of increasing interest and concern. These foods are typically stored at refrigeration temperatures suited to the survival of L. monocytogenes and are consumed without further processing. Since L. monocytogenes is ubiquitous in agricultural environments, the cultivation of fresh produce predisposes it to contamination. The contamination of RTE foods originates either from raw ingredients or, more commonly, from cross‐contamination within food‐processing facilities. Research on the food‐processing environment has been recommended to reduce the incidence of L. monocytogenes in foods. The consumption of contaminated foods by immunocompromised individuals causes invasive listeriosis, with a 20% to 30% fatality rate despite treatment. The emergence of antibiotic‐resistant strains has reduced the effectiveness of modern medicine and may increase morbidity and mortality. Without epidemiological surveillance and identifying trends in disease determinants, no action can be taken to improve food safety and mitigate the risk of such outbreaks. [ABSTRACT FROM AUTHOR]

Liquid smoke, an alternative to traditional wood burning smoking, enhances product value by imparting desirable characteristics such as aroma, flavor, and color. Furthermore, it contains components with inherent antimicrobial and antioxidant properties. This study compares the effects of liquid smoke and conventional smoking methods in bacon processing. Over a 90‐day storage period at 22°C, physical‐chemical stability, sensory attributes, and microbiological characteristics of the bacon were evaluated. The antimicrobial and antioxidant properties of liquid smoke were assessed. Liquid smoke exhibited antioxidant activity, with an inhibitory concentration (IC50) value of 0.19 mg/mL, indicating the concentration of the extract needed to inhibit 50% of DPPH (2,2′‐diphenyl‐1‐picrylhydrazyl) radicals. Moreover, it demonstrated antimicrobial effects against Escherichia coli, Salmonella choleraesius, Staphylococcus aureus, and Listeria monocytogenes, with a minimum bactericidal concentration ranging from 7.5% to 10%. Throughout the storage, bacon treated with liquid smoke showed no signs of rancid odor, supported by thiobarbituric acid reactive substances values below 0.85 mg MDA/kg (where MDA is malondialdehyde). The utilization of liquid smoke yielded visually attractive bacon with enhanced color attributes, including a distinct yellow and red hue, as well as increased luminosity and brightness, surpassing the effects of traditional smoke. Remarkably, liquid smoke application significantly reduced processing time from 30 h to approximately 5 h, leading to substantial cost savings in the processing phase. [ABSTRACT FROM AUTHOR]

Farmstead dairy processing facilities may be particularly susceptible to Listeria spp. contamination due to the close physical proximity of their processing environments (PE) to associated dairy farm environments (FE). In this case study, we supported the implementation of interventions focused on improving (1) cleaning and sanitation efficacy, (2) hygienic zoning, and (3) sanitary equipment and facility design and maintenance in a farmstead dairy processing facility, and evaluated their effect on Listeria spp. detection in the farmstead's PE over 1 yr. Detection of Listeria spp. in the farmstead's PE was numerically reduced from 50% to 7.5% after 1 yr of intervention implementation, suggesting that these interventions were effective at improving Listeria spp. control. In addition, environmental samples were also collected from the farmstead's FE to evaluate the risk of the FE as a potential source of Listeria spp. in the PE. Overall, detection of Listeria spp. was higher in samples collected from the FE (75%, 27/36) compared with samples collected from the PE (24%, 29/120). Whole-genome sequencing performed on select isolates collected from the PE and FE supported the identification of 6 clusters (range of 3 to 15 isolates per cluster) that showed ≤ 50 high-quality single nucleotide polymorphism differences. Of these 6 clusters, 3 (i.e., clusters 2, 4, and 5) contained isolates that were collected from both the PE and FE, suggesting that transmission between these 2 environments was likely. Moreover, all cluster 2 isolates represented a clonal complex of L. monocytogenes commonly associated with dairy farm environmental reservoirs (i.e., CC666), which may support that the farmstead's FE represented an upstream source of the cluster 2 isolates that were found in the PE. Overall, our data underscore that although the FE can represent a potential upstream source of Listeria spp. contamination in a farmstead dairy processing facility, implementation of targeted interventions can help effectively minimize Listeria spp. contamination in the PE. The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. [ABSTRACT FROM AUTHOR]

Summary: Pork cutlets are susceptible to cross‐contamination with foodborne pathogens during processing. Food irradiation effectively improves food hygiene by eliminating microbes. We investigated the application of X‐ray irradiation (0.5–10 kGy) on pathogen inactivation (D10 value), quality changes [total aerobic bacteria (TAB), yeast and mould (Y&M), total coliform (TC), colour, thiobarbituric acid reactive substance (TBARS), and pH], and the hydrocarbon profile of pork cutlets. D10 values of Escherichia coli O157:H7, Salmonella typhimurium, Listeria monocytogenes, and Staphylococcus aureus were 0.37, 0.62, 0.52, and 0.36 kGy, respectively. At least 3.10 kGy (5‐D10 values) is required to ensure the microbiological safety of pork cutlets. X‐ray irradiation dose‐dependently reduced all microbial counts, and up to 7 kGy had no adverse effects on colour, TBARS, and pH. Furthermore, 1,7‐hexadecadiene and 8‐heptadecene were potential markers for irradiated pork cutlets. X‐ray irradiation of up to 7 kGy is effective in improving hygiene levels while maintaining pork cutlet quality. [ABSTRACT FROM AUTHOR]

Background As the number of individuals receiving the coronavirus disease 2019 (COVID-19) vaccine continues to rise, we have observed a concurrent increase in myopericarditis cases within the general population. This case serves as a reminder of the necessity to approach such occurrences with an open mind. Additionally, it underscores the importance of employing multi-modal imaging techniques alongside a collaborative, multi-disciplinary approach when addressing complex medical cases. Case summary We present a case of a woman in her 50s attending the emergency department with pyrexia, lethargy, and chest pain following the AstraZeneca COVID-19 vaccine. She had a background of systemic lupus erythematosus that was treated with immunosuppressive medication. Initial assessments revealed abnormal electrocardiogram, elevated troponin, and raised inflammatory markers. A diagnosis of likely vaccine-induced myopericarditis was made. However, blood cultures revealed Listeria monocytogenes , and cardiac imaging confirmed a right atrial (RA) thrombus that was considered to be infected. Subsequently, she was treated for Listeria myopericarditis and infected thrombus with intravenous antibiotics and anticoagulation. The patient did not wish for any invasive investigations given her clinical improvement. This is the first case of Listeria -related myopericarditis with an infected thrombus in the RA. We saw the full resolution of RA mass with medical management. Discussion This case highlights the importance of multi-modality imaging techniques to facilitate the diagnosis of Listeria -related myopericarditis accompanied by an infected thrombus. It also emphasizes the importance of conducting interval scanning and follow-up assessments to ensure the resolution of the disease. To improve diagnostic accuracy, an endomyocardial biopsy can also be considered. [ABSTRACT FROM AUTHOR]

The consumption of organic food has increased in recent years. In organic rearing animals are exposed to outdoor conditions, which may increase their risk of infection from various pathogens. In the present study the occurrence of the most significant foodborne pathogenic bacteria in organic meat and ready-to-eat organic meat products was assessed. Out of 100 raw organic meat samples tested, 72 were contaminated with bacterial pathogens. The highest percentage of contaminated samples was observed in poultry meat (92.5%) followed by pork meat (66.7%). Furthermore, 50.0% of beef origin samples were positive for the bacteria tested. L. monocytogenes was found in 39.0% of samples, S. aureus was identified in 37.0%, Campylobacter in 20.0%, Salmonella in 8.0% and Shigatoxin-producing E. coli in 4.0% of raw meat samples. In 31.0% of samples a co-occurrence of two (83.9%) or three (16.1%) pathogens was observed. Among 100 samples of organic meat products tested, only L. monocytogenes was found in 5.0% of samples. The result of the present study indicated that organic food may be a source of harmful microorganisms that may pose foodborne infections to consumers. [ABSTRACT FROM AUTHOR]

The European Union (EU) regulations mandate 10% of all food packaging to be reusable by 2030. United States (U.S.) exporters of specialty crops face new challenges in ensuring microbiological food safety using reusable packaging. A novel antimicrobial formulation consisting of ammonium carboxylate salt of capric acid and L-arginine (GS-2) was recently developed as a spray coating chemical for food packaging materials. In this study, we evaluated the antimicrobial efficacy of GS-2 against microbial strains representing three foodborne bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica), one fungal spoilage organism (Aspergillus niger), and one surrogate viral pathogen (murine norovirus) on three reusable plastic materials (acrylonitrile butadiene styrene, high-density polyethylene, and polypropylene) and one cardboard packaging material, respectively. Different chemical concentrations, exposure times, and storage conditions were individually evaluated for the relative antimicrobial efficacies of GS-2 against these microorganisms. Our results showed that GS-2 was highly effective for inactivating bacterial pathogens on both plastic and cardboard surfaces. For instance, 3% GS-2 achieved a >5 log CFU/in2 reduction in E. coli O157:H7, L. monocytogenes, and S. enterica on tested plastic surfaces at an exposure time of 60 min. However, its efficacy against A. niger and murine norovirus was less optimal, resulting in a ≤1 log CFU/in2 reduction on all tested surfaces. Based on our study, GS-2 demonstrated a strong potential as an antibacterial coating reagent for reusable food packaging materials to minimize pathogen contamination and ensure the safety of the specialty crops. [ABSTRACT FROM AUTHOR]

Recent foodborne outbreaks and recalls involving Listeria monocytogenes and Salmonella-contaminated peaches have caused significant economic losses to the peach industry. This study evaluated the effectiveness of chlorine, a commonly used sanitizer in the fresh produce industry, against L. monocytogenes and Salmonella and its ability to control cross-contamination in fresh peaches. Peaches inoculated with L. monocytogenes or Salmonella (~6 log10 CFU/peach) were treated with 50–150 mg/L of free chlorine (FC, pH6.8) 24 h post-inoculation. The results revealed that chlorine had similar efficacy against L. monocytogenes and Salmonella on peaches (p > 0.05). A 30 s treatment at 50, 100, and 150 mg/L FC resulted in dose-dependent reductions (p < 0.05), achieving reductions of 0.88–0.92, 1.54–1.61, and 1.73–1.79 log10 CFU/peach, respectively. Extending the contact time to 2 min slightly but significantly enhanced the chlorine efficacy (p < 0.05). Additionally, a 30 s to 2 min exposure to chlorine with 50–150 mg/L FC resulted in a 1.05–1.43 log10 CFU/peach reduction in yeasts and molds. Tap water exposure led to substantial cross-contamination between inoculated and uninoculated fruits and processed water, with Salmonella exhibiting higher transfer rates than L. monocytogenes. The application of chlorine mitigated the cross-contamination of both pathogens but did not entirely prevent it. These findings offer valuable insights for the peach and other stone fruit industries to verify process controls. [ABSTRACT FROM AUTHOR]

Previous investigations have explored the involvement of wolves in parasitic and viral diseases, but data on the zoonotic bacteria are limited. The aim of this study was to assess the occurrence of bacterial zoonotic agents in 16 wolf (Canis lupus italicus) fecal samples collected in a protected area in Central Italy. Campylobacter spp., Salmonella spp., Yersinia spp., Listeria monocytogenes, and Shiga Toxin-Producing Escherichia coli (STEC) were investigated by culture, while polymerase chain reaction (PCR) was employed to detect Coxiella burnetii, Mycobacterium spp., Brucella spp., and Francisella tularensis. The presence of Extended Spectrum β-Lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae was also evaluated, using selective isolation media and detection of antimicrobial resistance genes. All samples were negative for Campylobacter spp., Salmonella spp., C. burnetii, Mycobacterium spp., Brucella spp., F. tularensis, and carbapenemase-producing Enterobacteriaceae. One sample tested positive for Yersinia aldovae and three for Yersinia enterocolitica BT1A. One L. monocytogenes (serogroup IIa) and one STEC, carrying the stx1 gene, were isolated. Two ESBL isolates were detected: one Serratia fonticola, carrying blaFONA-3/6 gene, and one Escherichia coli, carrying blaCTX-M-1 gene. Both ESBL isolates were resistant to different antimicrobials and therefore classified as multi-drug-resistant. Our data suggest that wolves are potential carriers of zoonotic bacteria and may contribute to the environmental contamination through their feces. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes causes listeriosis, a serious foodborne illness with a high mortality rate, especially in vulnerable populations. It accounts for 19% of foodborne deaths, with invasive cases having a mortality rate of up to 44%, leading to conditions like meningitis, bacteremia, and meningoencephalitis. However, the prognostic factors remain unclear. This study examines the hospital outcomes of invasive listeriosis and identifies risk factors for in-hospital and one-year mortality. We analyzed the electronic medical records of 118 hospitalized patients with non-perinatal, culture-proven invasive listeriosis collected over a 21-year period. The in-hospital mortality rate was 36.4%, with only 33.1% surviving one year and 22.0% surviving two years. The key findings indicate that a quick Sequential Organ Failure Assessment (qSOFA) score of ≥2 (OR 106.59, p < 0.001), respiratory failure (OR 7.58, p = 0.031), and shorter ampicillin duration (OR 0.53, p = 0.012) independently predicted poorer in-hospital outcomes. Additionally, a qSOFA score of ≥2 (OR 8.46, p < 0.001) and shorter ampicillin duration (OR 0.65, p < 0.001) were linked to higher one-year mortality. This study is the first to identify a qSOFA score of ≥2 as a significant marker for high-risk invasive listeriosis patients, with poorer outcomes linked to a qSOFA score of ≥2, respiratory failure, and shorter ampicillin use. [ABSTRACT FROM AUTHOR]

Background: Listeria monocytogenes, a Gram-positive intracellular bacillus, causes listeriosis, which is primarily transmitted through contaminated food and vertical transmission. The incidence of the disease is estimated to be between one and ten cases per million globally, with pregnant women being particularly vulnerable. Objective: The aim was to describe the clinical characteristics, management, and outcomes of cases of gestational listeriosis at Hospital Materno Infantil de Málaga in order to improve our understanding, diagnosis, and treatment of this disease. Methods: A retrospective analysis of six confirmed cases of listeriosis was performed in pregnant women or neonates. Diagnostic confirmation was achieved using analytic and microbiological methodologies, including blood cultures and the measurement of C-reactive protein (CRP). Ethical approval was obtained, and clinical data were reviewed for reasons related to consultation, treatment approaches, and complications. Results: The most frequently observed symptoms were fever and abdominal pain, with complications such as intrauterine death and suspected chorioamnionitis. Four patients were treated with antibiotics, leading to improved outcomes. No severe complications such as neurolisteriosis were observed. Conclusions: Pregnant women are more susceptible to L. monocytogenes, which can cause mild maternal symptoms but severe foetal outcomes, including prematurity, foetal death, or neonatal infections. Early diagnosis and prompt treatment are crucial for improving maternal–foetal outcomes. [ABSTRACT FROM AUTHOR]

Canada is a leading producer of wild lowbush blueberries, most of which are mechanically harvested, washed, individually quick frozen (IQF), and bulk packaged. Still, some berries are harvested by more gentle methods and sold as fresh-packed products. These berries do not undergo a wash step, nor are subjected to antimicrobial treatments. The purpose of this study was to conduct a microbiological survey of berries harvested in the province of Nova Scotia to assess their potential for harborage of bacterial foodborne pathogens. A combination of standardized plate count methods and 3M-Petrifilm protocols were used to enumerate total aerobic mesophilic bacteria (APC), yeasts and molds (YMC), coliforms, and generic E. coli, the latter being an indicator of fecal contamination. Overall, APC and YMC levels were 1.2 and 0.5 log greater, respectively, for berries collected early in the harvest season versus those acquired late season and varied significantly (p < 0.05) between farm (location) and harvest practices used. Berries harvested by our team using sanitized hand rakes (SH) had consistently lower APC and YMC levels than those harvested by farm crews. Yet, when gentle harvesting (GH) methods (hand-raking, walk-behind or modified mechanical harvesters) were employed on farms, lower numbers were generally observed compared to berries harvested by traditional tractor-mounted mechanized harvesters (MH). The presence of coliforms (and their levels) was also impacted by the harvest method, with detection rates of ~29%, 73%, and 92% in SH, GH, and MH samples, respectively. Mean counts were < 2.5 log10 CFU/g for both SH and GH berries, but significantly higher (p < 0.05) on MH berries (3.6 log10 CFU/g). Although ~56% of all berry samples collected (n = 350) contained coliforms, only 12 were positive for E. coli, 9 of which were MH samples. Only the latter had numbers > 2 log10 CFU/g, but none tested positive for Shiga toxin-producing serotype O157 (STEC O157) or Salmonella spp. when using internationally recognized selective enrichment and plating methods. ATP luminescence was used to assess the general hygiene of processing lines, whereby "hot spots" for microbial activity were identified, even after cleaning., Standard selective enrichment and plating methods were used for the detection of Listeria monocytogenes on 61 swab samples taken from berry totes or conveyor belts at different times during processing; 4 swabs tested positive for L. monocytogenes. However, the pathogen could not be detected by direct plating on selective agar without prior enrichment; this indicated its numbers were low. The results from this work demonstrated that alternative gentle harvest methods can reduce microbial numbers on wild blueberries. Although the frequency of fecal contamination in berry samples appeared to be low and targeted human pathogens were not detected; this represents a single study conducted over one harvest season. Therefore, it would be prudent for processors to seek effective antimicrobial technologies prior to packaging, while consumers should use caution and thoroughly wash produce before consumption. Where sporadic detection of L. monocytogenes was observed on environmental samples from the processing line, processors must ensure that effective sanitation programs are implemented to avoid potential food safety risks. [ABSTRACT FROM AUTHOR]

The rising prevalence of pathogenic bacteria in livestock meat poses a growing public health concern in China. The determination of antimicrobial resistance (AMR) is critical for the clinical management of foodborne infections stemming from livestock meat consumption. This study aimed to assess the prevalence of pathogenic bacteria in livestock meat (pork, beef, and mutton) sampled in China in 2021 and to identify the most common AMR patterns among the isolated pathogens. A total of 2515 raw livestock meat samples were collected across 15 provinces in China during 2021. Pathogen detection, including Listeria monocytogenes, Salmonella, and diarrheagenic Escherichia coli (DEC), followed China's national food safety standards. All Salmonella isolates underwent serotyping via slide agglutination. Antimicrobial susceptibility of Salmonella and DEC isolates was assessed using the broth dilution method. The detection rates for L. monocytogenes, Salmonella, and DEC in raw livestock meat were 9.06% (228/2, 515), 10.54% (265/2, 515), and 6.16% (155/2, 515), respectively. Pork showed the highest contamination rates for Salmonella and DEC, with prevalence rates of 17.60% (214/1, 216, χ2 = 124.62, p < 0.05) and 7.89% (96/1, 216, χ2 = 14.466, p < 0.05), respectively. L. monocytogenes contamination was notably higher in chilled (14.43%, 84/582) and frozen (12.39%, 55/444) meat than in fresh meat (χ2 = 43.510, p < 0.05). In contrast, Salmonella (12.09%, 180/1489, χ2 = 15.173, p < 0.05) and DEC (7.25%, 108/1489, χ2 = 12.275, p < 0.05) were more prevalent in fresh meat than in chilled or frozen samples. The predominant Salmonella serotypes identified were Salmonella enterica subsp. enterica serovar Typhimurium, followed by Salmonella enterica serovar Derby, Salmonella enterica serovar Rissen, Salmonella enterica serovar London, and Salmonella enterica serotype Enteritidis. Enteroaggregative E. coli was the most frequent pathotype among DEC (84.7%, 133/157), followed by enteropathogenic E. coli (8.3%, 13/157) and enterohemorrhagic E. coli (5.1%, 8/157). Among the 14 tested antimicrobial agents, Salmonella isolates demonstrated an overall resistance rate of 87.50%, while DEC exhibited a resistance rate of 84.70%. Ampicillin and tetracycline showed the highest resistance rates in both pathogens. Multi-drug resistance (MDR) was observed in 67.53% of Salmonella isolates (183 isolates) and 57.96% of DEC isolates (91 isolates). This study highlights the significant contamination of retail raw livestock meat in China by L. monocytogenes, Salmonella, and DEC. The high resistance of MDR in both pathogens poses serious public health risks. Chinese food safety and veterinary authorities should implement stricter measures to control pathogen contamination and regulate the use of antimicrobials in livestock to mitigate these risks. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a foodborne pathogen that causes listeriosis in humans, the severity of which depends on multiple factors, including intrinsic characteristics of the affected individuals and the pathogen itself. Additionally, emerging evidence suggests that epigenetic modifications may also modulate host susceptibility to infection. Therefore, different clinical outcomes can be expected, ranging from self-limiting gastroenteritis to severe central nervous system and maternal-neonatal infections, and bacteremia. Furthermore, L. monocytogenes is a genetically and phenotypically diverse species, resulting in a large variation in virulence potential between strains. Multilocus sequence typing (MLST) has been widely used to categorize the clonal structure of bacterial species and to define clonal complexes (CCs) of genetically related isolates. The combination of MLST and epidemiological data allows to distinguish hypervirulent CCs, which are notably more prevalent in clinical cases and typically associated with severe forms of the disease. Conversely, other CCs, termed hypovirulent, are predominantly isolated from food and food processing environments and are associated with the occurrence of listeriosis in immunosuppressed individuals. Reports of genetic traits associated with this diversity have been described. The Food and Agriculture Organization (FAO) is encouraging the search for virulence biomarkers to rapidly identify the main strains of concern to reduce food waste and economical losses. The aim of this review is to comprehensively collect, describe and discuss the methodologies used to discriminate the virulence potential of L. monocytogenes CCs. From the exploration of in vitro and in vivo models to the study of expression of virulence genes, each approach is critically explored to better understand its applicability and efficiency in distinguishing the virulence potential of the pathogen. [ABSTRACT FROM AUTHOR]

Background/Objectives: Listeria monocytogenes is a foodborne pathogen that can infect both humans and animals and cause noninvasive gastrointestinal listeriosis or invasive listeriosis. The objectives of this study were to determine the genetic diversity of L. monocytogenes; the genes associated with its resistance to antibiotics, benzalkonium chloride (BC), and cadmium chloride (CdCl2); and its biofilm formation. Methods: A total of 132 fresh fruits (44 samples) and vegetables (88 samples) were selected for this study. The genetic diversity of the isolates and the genes associated with their antibiotic resistance were determined using PCR amplification; meanwhile, their levels of susceptibility to antibiotics were determined using the agar diffusion method. Their levels of resistance to BC and CdCl2 were determined using the minimum inhibitory concentration method, and their capacity for biofilm formation was evaluated using the crystal violet staining method. Results: A total of 17 L. monocytogenes strains were collected: 12.8% (17/132) from fresh fruits and vegetables in this study. The isolates of L. monocytogenes belonged to phylogenetic groups I.1 (29.4% (5/17); serotype 1/2a) and II.2 (70.5% (12/17); serotype 1/2b); strains containing Listeria pathogenicity islands (LIPIs) were also identified at prevalence rates of 100% for LIPI-1 and LIPI-2 (17/17), 29.4% for LIPI-3 (5/17), and 11.7% for LIPI-4 (2/17). The antibiotic susceptibility tests showed that the L. monocytogenes isolates exhibited six different multiresistant patterns, with multiple antibiotic resistance (MAR) index of ≥0.46 (70.5%; 12/17); additionally, the genes Ide, tetM, and msrA, associated with efflux pump Lde, tetracycline, and ciprofloxacin resistance, were detected at 52.9% (9/17), 29.4% (5/17), and 17.6% (3/17), respectively. The phenotypic tests showed that 58.8% (10/17) of cadmium-resistant L. monocytogenes isolates had a co-resistance of 23.5% (4/17) to BC. Finally, all strains of L. monocytogenes exhibited moderate biofilm production. Conclusions: The results of this study contribute to our understanding of the persistence and genetic diversity of L. monocytogenes strains isolated from fresh fruits and vegetables; in addition, their resistance to CdCl2, which is correlated with co-resistance to BC disinfectant, is helpful for the food industry. [ABSTRACT FROM AUTHOR]

This study investigates seasonal biomass variations in Betaphycus gelatinus, a red alga cultivated in the field in Ninh Thuan, Vietnam, along with the chemical composition, structural properties, and bioactivity of its carrageenan. Monthly measurements over a one-year period revealed peak growth (2.02% per day) and carrageenan yield (59.61%) in June, identifying it as the optimal harvest period. FTIR and NMR analyses of carrageenan extracted from field-cultivated B. gelatinus showed hybrid κ- and β-carrageenan forms and a unique pyruvylated β-carrageenan structure not previously reported for this species. Bioactivity assays indicated high antioxidant potential, with a total antioxidant capacity equivalent to 48.30 mg ascorbic acid/g carrageenan and an ABTS radical scavenging IC50 of 3.64 µg/mL. Additionally, antibacterial tests demonstrated strong inhibition of Listeria monocytogenes (12.00 mm inhibition zone). These findings suggest that field cultivation is a sustainable approach for carrageenan production, yielding bioactive compounds with promising applications in pharmaceuticals, cosmetics, and food preservation as a viable alternative to wild harvesting. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes (LM) is a Gram‐positive (G+) bacterium that secretes nanoscale membrane vesicles (MVs). LM MVs comprise various bacterial components and may have potential as an antigen or drug‐delivery vehicle; however, the low yield of the LM MVs limits related research. G+‐bacterial MVs germinate from the bacterial plasma membrane and must pass through a thick crosslinked peptidoglycan layer for release. Herein, we aimed to increase the release of MVs by reducing the degree of crosslinking of peptidoglycan. We knocked out two genes related to the longitudinal crosslinking of peptidoglycan, dal and dat, and supplemented the knocked‐out dal gene through plasmid expression to obtain a stably inherited recombinant strain LMΔdd::pCW633. The structure, particle size, and main protein components of MVs secreted by this recombinant strain were consistent with those secreted from the wild strain, but the yield of MVs was considerably increased (p < 0.05). Furthermore, Listeria ivanovii (LI) was found to secrete MVs that differed in the composition of the main proteins compared with those of LM MVs. The abovementioned method was also feasible for promoting the secretion of MVs from the attenuated LM strain and LI wild‐type and attenuated strains. Our study provides a new method to increase the secretion of MVs derived from Listeria that could be extended to other G+ bacteria. [ABSTRACT FROM AUTHOR]

Copyright of Microbes & Infectious Diseases is the property of Microbes & Infectious Diseases and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Microbes & Infectious Diseases is the property of Microbes & Infectious Diseases and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Infection by bacteria leads to tissue damage and inflammation, which need to be tightly controlled by host mechanisms to avoid deleterious consequences. It is previously reported that TMEM16F, a calcium‐activated lipid scramblase expressed in various immune cell types including T cells and neutrophils, is critical for the control of infection by bacterium Listeria monocytogenes (Lm) in vivo. This function correlated with the capacity of TMEM16F to repair the plasma membrane (PM) damage induced in T cells in vitro, by the Lm toxin listeriolysin O (LLO). However, whether the protective effect of TMEM16F on Lm infection in vivo is mediated by an impact in T cells, or in other cell types, is not determined. Herein, the immune cell types and mechanisms implicated in the protective effect of TMEM16F against Lm in vivo are elucidated. Cellular protective effects of TMEM16F correlated with its capacity of lipid scrambling and augment PM fluidity. Using cell type‐specific TMEM16F‐deficient mice, the indication is obtained that TMEM16F expressed in liver Kupffer cells (KCs), but not in T cells or B cells, is key for protection against Listeria in vivo. In the absence of TMEM16F, Listeria induced PM rupture and fragmentation of KCs in vivo. KC death associated with greater liver damage, inflammatory changes, and dysregulated liver metabolism. Overall, the results uncovered that TMEM16F expressed in Kupffer cells is crucial to protect the host against Listeria infection. This influence is associated with the capacity of Kupffer cell‐expressed TMEM16F to prevent excessive inflammation and abnormal liver metabolism. [ABSTRACT FROM AUTHOR]

High-pressure processing (HPP) is a promising technology for increasing the shelf life of food, with minimal effects on the nutritional or sensory quality. However, there has been a concern that high-oil-content foods may protect food pathogens in HPP, and that HPP can affect the quality of lipids. We inoculated Listeria monocytogenes and Salmonella Typhimurium into 34% and 54% oil-content pesto sauce, processed them either with HPP (600 MPa, 4 min) or thermal processing (82 °C, 5 min), and analyzed bacteria counts, pH, GC-MS (Terpene compounds), the time–kill kinetic study, and lipid oxidation value for 60 days in refrigerating storage (5 ± 2 °C). Our findings show that HPP significantly reduced the number of bacteria (more than 4-log) compared to thermal processing or non-processing. Additionally, we discovered terpene compounds (highest-level terpene: L-linalool, eugenol, and 1,8-cineol) in pesto oil that exhibit antimicrobial activity. Different oil content did not have any significant effect on bacteria levels. Regarding chemical results, all samples were of acceptable quality, and the processes did not show any negative effect on lipid oxidation (Peroxide and P-Anisidine value under 10 meq per kilogram of oil). In conclusion, our study indicates that HPP is a suitable method for high-oil-content pesto sauce. In addition, functional compounds naturally present in pesto may contribute to maintaining its microbial and chemical quality. [ABSTRACT FROM AUTHOR]

In recent years, the awareness of healthier lifestyles among consumers has driven to an increased interest in more natural, nutritious, and low-processed foods. Ferulic acid, one of the most abundant phenolic acids in plants, has demonstrated a wide spectrum of antimicrobial activities and a range of biomedical effects, including antioxidant, antiallergic, hepatoprotective, anticarcinogenic, anti-inflammatory, and antithrombotic, among others. The objective of this work was to study the antilisterial effect of ferulic acid (FA, 1500 mg/L) on fresh, ready-to-eat orange (FOJ) and apple (FAJ) juices and evaluate its effect on product quality. The results showed that FA reduced the Listeria monocytogenes population after 9 days of storage at 4 °C, but no effect on the indigenous microbiota was observed. The titratable acidity and color significantly changed. The antioxidant capacity and total phenolic content significantly increased with the addition of FA, being at least two times greater in fortified juices. FAJ and FOJ containing FA were scored lower (6.8 and 5.7 on a 9-point hedonic scale, respectively) than their respective controls. Overall, our results demonstrated that FA treatment could be a useful strategy to maintain the safety of fresh apple and orange juices and increase the antioxidant activity and phenolic content. The potential industrial applications and health benefits of the fortification of fruit juices with FA should be further explored. [ABSTRACT FROM AUTHOR]

Calcium (Ca2+) signaling is fundamental to cellular processes in both eukaryotic and prokaryotic organisms. While the mechanisms underlying eukaryotic Ca2+ transport are well documented, an understanding of prokaryotic transport remains nascent. LMCA1, a Ca2+ adenosine triphosphatase (ATPase) from Listeria monocytogenes, has emerged as a prototype for elucidating structure and dynamics in prokaryotic Ca2+ transport. Here, we used a multidisciplinary approach integrating kinetics, structure, and dynamics to unravel the intricacies of LMCA1 function. A cryo-electron microscopy (cryo-EM) structure of a Ca2+-bound E1 state showed ion coordination by Asp720, Asn716, and Glu292. Time-resolved x-ray solution scattering experiments identified phosphorylation as the rate-determining step. A cryo-EM E2P state structure exhibited remarkable similarities to a SERCA1a E2-P* state, which highlights the essential role of the unique P-A domain interface in enhancing dephosphorylation rates and reconciles earlier proposed mechanisms. Our study underscores the distinctiveness between eukaryotic and prokaryotic Ca2+ ATPase transport systems and positions LMCA1 as a promising drug target for developing antimicrobial strategies. [ABSTRACT FROM AUTHOR]

Background: Foodborne infections such as listeriosis caused by the bacterium Listeria monocytogenes represent a significant public health concern, particularly when outbreaks affect many individuals over prolonged time. Systematic collection of pathogen isolates from infected patients, whole genome sequencing (WGS) and phylogenetic analyses allow recognition and termination of outbreaks after source identification and risk profiling of abundant lineages. Methods: We here present a multi-dimensional analysis of > 1800 genome sequences from clinical L. monocytogenes isolates collected in Germany between 2018 and 2021. Different WGS-based subtyping methods were used to determine the population structure with its main phylogenetic sublineages as well as for identification of disease clusters. Clinical frequencies of materno-foetal and brain infections and in vitro infection experiments were used for risk profiling of the most abundant sublineages. These sublineages and large disease clusters were further characterised in terms of their genetic and epidemiological properties. Results: The collected isolates covered 62% of all notified cases and belonged to 188 infection clusters. Forty-two percent of these clusters were active for > 12 months, 60% generated cases cross-regionally, including 11 multinational clusters. Thirty-seven percent of the clusters were caused by sequence type (ST) ST6, ST8 and ST1 clones. ST1 was identified as hyper- and ST8, ST14, ST29 as well as ST155 as hypovirulent, while ST6 had average virulence potential. Inactivating mutations were found in several virulence and house-keeping genes, particularly in hypovirulent STs. Conclusions: Our work presents an in-depth analysis of the genomic characteristics of L. monocytogenes isolates that cause disease in Germany. It supports prioritisation of disease clusters for epidemiological investigations and reinforces the need to analyse the mechanisms underlying hyper- and hypovirulence. [ABSTRACT FROM AUTHOR]

The presence of pathogens in food has increased awareness of food safety, but it also causes large economic losses. Fresh meat and meat products contain a sufficient quantity of proteins, lipids, water, and a favorable pH that stimulates the growth of various microorganisms, including pathogens. The aim of this study was to investigate the efficacy of Brevibacillus laterosporus BGSP7 (CFS-BGSP7) and BGSP9 (CFS-BGSP9) cellfree supernatants in the control of Listeria monocytogenes and Staphylococcus aureus in raw meat and meat products. Raw meat and meat products were sliced and then aseptically treated by immersion for 2 minutes into solutions containing: i) CFS-BGSP7; ii) CFS-BGSP9; iii) no treatment. The samples were then artificially contaminated with: Group I - L. monocytogenes (~4 log cfu g-1); Group II - S. aureus LMM322 (~4 log cfu g-1). Each sample was individually aseptically vacuum-packed and stored at 4°C for 8 weeks. The number of surviving bacteria in the samples were analyzed immediately after contamination with L. monocytogenes and S. aureus and at regular time-intervals: after 1, 3, 5 and 8 weeks of storage at 4°C. Meat samples treated with CFS-BGSP7 and CFS-SP9 showed a significant decrease in the cell counts of L. monocytogenes and S. aureus. When meat samples treated with CFS-BGSP7 and CFS-BGSP9 are compared, the results show a more intense reduction rate of both L. monocytogenes and S. aureus in all samples treated with CFS-BGSP7. [ABSTRACT FROM AUTHOR]

Χαλλούμι (Halloumi)/Hellim is the traditional cheese of Cyprus and belongs to the whole Island with Turkish and Greek names. Especially with the spotlights more on the product nowadays. In the current study, cheese samples were collected as fresh and mature halloumi/hellim (sheep/goat, bovine, or both milk) and were analyzed to evaluate the physicochemical and microbiological status. As a physicochemical analysis, the potential of hydrogen (pH), titratable acidity (TA), salt-sodium chloride (NaCl), and dry-matter (DM) ratios were analyzed. For examining the quality and safety indicators; total mesophilic aerobic bacteria (TMAB), yeast and molds, lactic acid bacteria (LAB), coliform bacteria, coagulase-positive staphylococci, Listeria monocytogenes, Salmonella spp. analyzes were performed. This study will help to establish the quality profile of halloumi/hellim cheese and identify potential hazards and sources of contamination. [ABSTRACT FROM AUTHOR]

Multiplex PCR has shown to be a useful technique for identifying Listeria monocytogenes and Staphylococcus aureus in food items. It can also be used to trace toxins to enhance food safety. This study identifies Listeria monocytogenes and Staphylococcus aureus in processed beef meat products using multiplex PCR. These bacteria were found in the beef meat samples using the 16SrRNA gene of L. monocytogenes and the 23S rRNA gene of S. aureus. For this study, 40 processed meat samples—ten samples of each minced meat, beef sausage, beef burger, and beef kofta— were gathered from different supermarkets in the El-Menoufia governorate. One important byproduct produced during the culinary processing of pomegranates is the peels from the fruits. Due to their plentiful presence of broad-spectrum antibacterial agents and antioxidants, these peels can effectively prevent food spoilage. The primary objective of the study was to determine whether pomegranate peel extract had any antimicrobial effects on Listeria monocytogenes and Staphylococcus aureus in minced beef. Also, the antioxidant and antibacterial properties of a hydromethanolic extract from sweet orange (Citrus sinensis) peel were examined. The results indicated that an extract from the peel of the Citrus sinensis tree has antibacterial effects against S. aureus and Listeria monocytogenes. [ABSTRACT FROM AUTHOR]

This study was designed to find out the prevalence of Listeria monocytogenes in raw milk and some dairy products and the molecular identification of their virulence genes. One hundred and twenty samples in all, including milk, Kareish cheese, and yogurt (40 of each), were gathered randomly from various sources for this study and examined for the presence of Listeria monocytogenes. Eight distinct strains of L. monocytogenes were identified and molecularly examined for 16 srRNA-specific genes for Listeria monocytogenes, as well as the identification of many pathogenicity genes (inlA, inlB, hlyA, and prfA genes). All eight isolates harbored 16srRNA-specific genes for Listeria monocytogenes; seven isolates harbored both inlA and inlB; six isolates harbored hlyA; and five isolates harbored the prfA gene. The results of antimicrobial susceptibility testing showed high sensitivity to Ciprofloxacin (CP), Gentamycin (CN), Vancomycin (VA), Doxycycline (DO), and Trimethoprim-sulfamethoxazole (SXT) with 100, 87.5, 87.5, 78.5, and 62.5%, respectively, while showing high resistance to Ampicillin (AM), Amoxicillin (AX), Oxicillin (OX), Erythromycin (E), Lincomycin (L), and Ceftriaxone (CRO) with 100, 100, 100, 100, and 75%, respectively. All eight Listeria monocytogenes isolates were multidrug-resistant, holding a variety of antibiotic resistance indexes (MARI) in the range of 0.417-0.833. In conclusion, the study's findings highlight the necessity of implementing more stringent sanitary control procedures, particularly while processing, storing, and marketing dairy products. The pasteurization temperatures must not be less than 85 °C, where only 85% of the bacteria are destroyed by pasteurization at 71-75 °C for 15 seconds. [ABSTRACT FROM AUTHOR]

Sprouts are popular due to their high nutritional content, including vitamins, minerals, antioxidants, and enzymes. However, the conditions favorable for sprouting, such as warm and humid environments, are also ideal for the growth of bacteria, including food‐borne pathogens. Here, we analyzed the growth and developed predictive models of locally isolated and commercial strains of Salmonella enterica and Listeria monocytogenes in alfalfa sprouts under various constant temperatures, ranging from 5°C to 25°C. Our findings indicated that these pathogens could grow at 5°C in sprouts, albeit with a low growth rate. A rapid increase in concentration occurred at temperatures of 10°C and above. The fitted models demonstrated high performance, with R2 values ranging from 0.964 to 0.997 and RMSE values ranging from 0.15 to 0.51, respectively. Based on the fitted values, bias factor (Af) values varied between 1.01 and 1.06, with all accuracy factor (Bf) values at 1.00. Acceptable prediction zone (APZ) values ranged from 81.8% to 100%. Validation of the models under dynamic temperature conditions for specific strains showed acceptable performance. This study enhances our understanding of S. enterica and L. monocytogenes growth in alfalfa sprouts. The findings of this study could be used to improve the risk assessment of these pathogens in alfalfa sprouts. [ABSTRACT FROM AUTHOR]

Bacteria adapt the biosynthesis of their envelopes to specific growth conditions and prevailing stress factors. Peptidoglycan (PG) is the major component of the cell wall in Gram‐positive bacteria, where PASTA kinases play a central role in PG biosynthesis regulation. Despite their importance for growth, cell division and antibiotic resistance, the mechanisms of PASTA kinase activation are not fully understood. ReoM, a recently discovered cytosolic phosphoprotein, is one of the main substrates of the PASTA kinase PrkA in the Gram‐positive human pathogen Listeria monocytogenes. Depending on its phosphorylation, ReoM controls proteolytic stability of MurA, the first enzyme in the PG biosynthesis pathway. The late cell division protein GpsB has been implicated in PASTA kinase signalling. Consistently, we show that L. monocytogenes prkA and gpsB mutants phenocopied each other. Analysis of in vivo ReoM phosphorylation confirmed GpsB as an activator of PrkA leading to the description of structural features in GpsB that are important for kinase activation. We further show that ReoM phosphorylation is growth phase‐dependent and that this kinetic is reliant on the protein phosphatase PrpC. ReoM phosphorylation was inhibited in mutants with defects in MurA degradation, leading to the discovery that MurA overexpression prevented ReoM phosphorylation. Overexpressed MurA must be able to bind its substrates and interact with ReoM to exert this effect, but the extracellular PASTA domains of PrkA or MurJ flippases were not required. Our results indicate that intracellular signals control ReoM phosphorylation and extend current models describing the mechanisms of PASTA kinase activation. [ABSTRACT FROM AUTHOR]

Infective endocarditis (IE) is a disease associated with significant morbidity and mortality. It is more commonly caused by Gram-positive cocci, but Gram-positive bacilli may seldom cause the disease. Listeria monocytogenes is an aerobic Gram-positive coccobacillus and a foodborne and opportunistic pathogen most commonly causing gastrointestinal infections, even though bacteremia, sepsis, meningitis, and fetal infections may also occur. Listeria IE has rarely been described, with most reports being case reports or case series. Thus, the characteristics of this disease remain largely unknown. This systematic review aimed to present all published Listeria IE studies and describe their characteristics. A search of PubMed, Scopus, and the Cochrane Library for studies providing information on epidemiology, clinical findings, treatment, and outcome of Listeria IE cases was performed. A total of 54 studies containing data from 62 patients were included. Among all patients, 64.5% were male; the median age was 69 years. Among all patients, 54.8% had a history of a prosthetic valve. The aortic valve was the most commonly affected, followed by the mitral. Fever, heart failure, and embolic phenomena were the most commonly encountered clinical findings. The only isolated species was L. monocytogenes. Antimicrobial resistance was relatively low for aminopenicillins and aminoglycosides, the most commonly used antimicrobials for treating L. monocytogenes IE. Surgery was performed in 27.4% of patients. Mortality was 37.1%. Patients who survived were more likely to have had a prosthetic valve, to have necessitated transesophageal echocardiography for the diagnosis, to have mitral valve IE, and to have had surgical management; however, no factor was identified in a multivariate logistic regression model as an independent factor for overall mortality. [ABSTRACT FROM AUTHOR]

Theaflavin 3,3′‐digallate (TF3), a major polyphenolic component of black tea, exhibits antibacterial effects against many foodborne pathogens. However, the antibacterial mechanisms of TF3 against Listeria monocytogenes remain unclear. In this study, we investigated the effects of TF3 on viability, biofilm, and membrane function of L. monocytogenes by the conventional plating method, crystal violet staining, and microscopy using fluorescent dyes JC‐1 and Laurdan, respectively. It was found that TF3 showed excellent antibacterial activity against L. monocytogenes with the minimum inhibitory concentration of 62.5 mg/L. The viable count determined on TSA decreased by 3 log after the treatment for 2 h with TF3 at 62.5 mg/L. The viable count determined on TSA containing 4% NaCl decreased by more than 4 log after the treatment for 30 min with TF3 at the same concentration, suggesting that TF3 gave damage on the cells, enhancing the antibacterial action of 4% NaCl, but the damage was recoverable in the absence of 4% NaCl. To explore the antibacterial mechanisms of TF3, the effects of TF3 on membrane potential and membrane fluidity were investigated. TF3 reduced both membrane potential and fluidity of L. monocytogenes at 62.5 mg/L, suggesting that TF3 damaged the structural integrity of the cell membrane. TF3 reduced biofilm mass of mature biofilm of L. monocytogenes. Moreover, THEAFLAVIN TF40, a commercially available Camellia sinensis leaf extract containing TF3, reduced viable count of L. monocytogenes by 2 log on apple skin. These results suggest the potential of theaflavins as a natural anti‐Listeria disinfectant. [ABSTRACT FROM AUTHOR]

Summary: Persistent bacteria are subset of cells capable of surviving bactericidal treatments longer. They originate in response to environmental stressors and show a longer lag phase compared to the rest of the population they are part of. Impact of persistent cells on food safety and role of common food preservation techniques in their formation are still unclear. This study aims to investigate whether osmotic stress induces formation of persistent cells in Listeria monocytogenes capable of resisting longer during cooking cycle of pork sausages. Lag‐phase duration at single‐cell level of a strain grown in 6%‐NaCl broth using image processing software was first investigated. Then, trend of the strain inactivation curve was evaluated in experimentally contaminated pork sausages cooked at 65 °C for 11 min. Results showed that salt triggers the formation of persistent cells characterised by a longer lag phase and increased heat resistance, posing a concern especially for ready‐to‐eat foods. [ABSTRACT FROM AUTHOR]

Biofilm formation on abiotic surfaces in the food industry is a major public health problem. Indeed, biofilms represent a constant source of pathogens, such as Listeria monocytogenes and bacteria of the genus Salmonella. Formation of multispecies biofilms by pathogens and spoilage microorganisms significantly contributes to the persistence of microorganisms in meat processing plant environments and thus poses a serious risk for product safety. In this study, 46 strains of microorganisms isolated from food products and various elements of food industry environment were tested for their ability to form biofilms at different temperatures. The analyzed pathogenic strains (Listeria monocytogenes and Salmonella sp.) and spoilage microorganisms (Pseudomonas sp.) exhibited adhesion to abiotic surfaces with subsequent formation of persistent biofilms. Low positive temperature was not a limiting factor in their ability to form biofilms. After 24 h of incubation at 4°C, Listeria and Salmonella sp. developed stable biofilms. It was found that these bacteria were capable of forming biofilms on various abiotic surfaces present in the meat industry (ceramic tiles, glass, and plastic). Analysis of synergistic interactions among members of the genera Listeria, Salmonella, and Pseudomonas in the formation of mixed biofilms at 4°C showed that combinations of a pathogenic microorganism and a Pseudomonas member formed biofilms significantly more efficiently than combinations of two pathogens. This indicates the importance of Pseudomonas species in synergistic interaction among microorganisms. [ABSTRACT FROM AUTHOR]

New nitrobenzyl-pyridyl ether ligands were synthesized by reacting nitrobenzyl bromide (2-, 3- and 4-nitro) and halogen-substituted hydroxy pyridine (2-chloro-3-hydroxy-pyridine, 2-bromo-3-hydroxy-pyridine) compounds in DMF. By interacting the obtained ligands (L1, L3, L4 and L6) with silver (I) nitrate, transition metal complexes were prepared (AgL1, AgL3, AgL4 and AgL6). The structures of the synthesized ligands and complexes were characterized using FTIR, HRMS, 1H-NMR and 13C-NMR spectroscopic techniques. In addition, fluorescence spectra of the ligands (L1-L6) were detected in the presence of different metal cations (Li+, Na+, Mg2+, Al3+, K+, Ca2+, Cr3+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Ag+). In addition, the thermal behavior of all compounds were examined by TGA-DTA methods and the data of silver complexes and ligands were compared. Within the scope of the study, the antibacterial activities of all compounds were investigated against 4 pathogens, 2 of which were plant-borne (Xanthomonas vesicotoria, Clavibacter michiganensis subsp. Michiganensis) and 2 were food-borne (Escherichia coli, Listeria monocytogenes). [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a human opportunistic foodborne pathogen that produces life-threatening infections with a high mortality rate. The control of Listeria in the food production environment and effective clinical management of human listeriosis are challenging due to the emergence of antibiotic resistance. Hence we evaluate the in vitro anti-Listeria activity of two synthetic cruzioseptins reproducing their natural sequences CZS-9, and CZS-12, and one engineered sequence based on CZS-1, named [K4K15]CZS-1. The assessment of the in vitro potential of cruzioseptins, highlighted the promising antibacterial effect of [K4K15]CZS-1 in very low concentrations (0.91 μM) and its thermal stability at high-temperature conditions, is compatible with the food industry. Microscopic and metabolomic analyses suggest cruzioseptin induces anti- Listeria bioactivity through membrane disruption and changes in the intracellular metabolome. We also report that [K4K15]CZS-1 is not resistant to peptidases/proteases emphasizing a key advantage for their use as a food preservative. However, there is a need for further structural and functional optimisations for the potential clinical application as an antibiotic. In conclusion, [K4K15]CZS-1 stand out as membrane-active peptides with the ability to induce shifts in the bacteria metabolome and inspire the development of strategies for the prevention of L. monocytogenes emergence and dissemination. • Frog Antimicrobial Peptides (AMPs) are an alternative bioactive for controlling listeriosis. • The cationic net charge is important to the potency of anti-Listeria activity. • Cruzioseptins can induce intracellular changes in the biological pathways of bacteria. • Engineered cruzioseptin is thermostable and retains bioactivity. [ABSTRACT FROM AUTHOR]