[On two cases of systemic listeriosis without dominant neurological compromise]. / Sobre dos casos de listeriosis sistémica sin compromiso neurológico dominante.

Listeria monocytogenes is a Gram-positive aerobic bacterium; found ubiquitously in nature; which mainly affects newborns, older adults, immunosuppressed patients and pregnant women. However, Listeria disease can occur in the healthy population. Invasive listeriosis has three dominant clinical forms, bacteremia, neurolisteriosis and maternal-neonatal infection. Localized forms are infrequently described. The disease occurs mainly secondary to the consumption of contaminated food, including unpasteurized milk or cheese, and occurs in the form of isolated cases or outbreaks, usually beginning a few days after consumption of the contaminated food; although it has been described up to 2 months after ingesting them. There is also the possibility of direct transmission from animals and vertical transmission. Systemic listeriosis without dominant neurological symptoms is a rare event. Two cases are presented. The first was spondylodiscitis in a normal host and the second was Listeria bacteremia in a febrile immunocompromised patient.

Listeria monocytogenes es una bacteria aeróbica Gram positiva; encontrada enforma ubicua en la naturaleza; que afecta sobre todo a recién nacidos, adultos mayores, pacientes inmunodeprimidos y mujeres embarazadas. Sin embargo, la enfermedad por Listeria puede ocurrir en la población sana. La listeriosis invasiva posee 3 formas clínicas dominantes, bacteriemia, neurolisteriosis e infección materno-neonatal. Las formas localizadas se describen infrecuentemente. La enfermedad se produce fundamentalmente en forma secundaria al consumo de alimentos contaminados, incluidos leche o queso no pasteurizados, y sepresenta en forma de casos aislados o brotes, soliendo comenzar a los pocos días del consumo de éstos; aunque se ha descripto hasta 2 meses después de ingerirlos. También existela posibilidad de transmisión directa desde animales y transmisión vertical. La listeriosis sistémica sin cuadro neurológico dominante es un evento raro. Se presentan dos casos. El primero, una espondilodiscitis en huésped normal y el segundo una bacteriemia por Listeria en un paciente inmunocomprometido febril.

Hybridization-driven synchronous regeneration of biosensing interfaces for Listeria monocytogenes based on recognition of fullerol to single- and double-stranded DNA.

A novel sensitive and reusable electrochemical biosensor for Listeria monocytegenes DNA has been constructed based on the recognition of water-soluble hydroxylated fullerene (fullerol) to single- and double-stranded DNA. First, the fullerol was electrodeposited on glassy carbon electrode (GCE), acting as a matrix for non-covalent adsorption of single-stranded probe DNA. Upon hybridization with the target DNA, the double helix structure was formed and desorbed from the electrode surface, driving synchronous regeneration of the biosensing interfaces. The biosensor showed a probe DNA loading density of 144 pmol∙cm-2 with the hybridization efficiency of 72.2%. The biosensor is applicable for the analysis of target DNA in actual milk samples with recoveries between 101.0% and 104.0%. This sensing platform provides a simple method for the construction of sensitive and reusable biosensor to monitor Listeria monocytogenes-related food pollution.

Comparative growth kinetics of Listeria monocytogenes and Salmonella enterica on dehydrated enoki and wood ear mushrooms during rehydration and storage.

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

TMEM16F Expressed in Kupffer Cells Regulates Liver Inflammation and Metabolism to Protect Against Listeria Monocytogenes.

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.

Transition to Whole Genome Sequencing Surveillance: The Impact on National Outbreak Detection and Response for Listeria monocytogenes, Salmonella, Shiga Toxin-Producing Escherichia coli, and Shigella Clusters in Canada, 2015-2021.

Between 2017 and 2019, pulsed-field gel electrophoresis was replaced by whole genome sequencing (WGS) for identifying enteric disease clusters in Canada. The number and characteristics of all clusters of Listeria monocytogenes, Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Shigella spp. between 2015 and 2021 were analyzed. Following the transition to WGS, an increase in the number of Salmonella, STEC, and Shigella clusters was noted, whereas the number of clusters of L. monocytogenes decreased. Unlike previous subtyping methods, WGS provided increased resolution to identify discrete clusters of Salmonella Enteritidis. This led to the identification of a number of outbreaks linked to frozen raw breaded chicken products and ultimately a change in food safety policy to reduce the number of illnesses associated with these products. Other pathogens did not experience a similar increase in the number of outbreaks detected. Although WGS did provide increased confidence in the genetic relatedness of cases and isolates, challenges remained in collecting epidemiological data to link these illnesses to a common source.

The host GTPase Dynamin 2 modulates apical junction structure to control cell-to-cell spread of Listeria monocytogenes.

The food-borne pathogen Listeria monocytogenes uses actin-based motility to generate plasma membrane protrusions that mediate the spread of bacteria between host cells. In polarized epithelial cells, efficient protrusion formation by L. monocytogenes requires the secreted bacterial protein InlC, which binds to a carboxyl-terminal Src homology 3 (SH3) domain in the human scaffolding protein Tuba. This interaction antagonizes Tuba, thereby diminishing cortical tension at the apical junctional complex and enhancing L. monocytogenes protrusion formation and spread. Tuba contains five SH3 domains apart from the domain that interacts with InlC. Here, we show that human GTPase Dynamin 2 associates with two SH3 domains in the amino-terminus of Tuba and acts together with this scaffolding protein to control the spread of L. monocytogenes. Genetic or pharmacological inhibition of Dynamin 2 or knockdown of Tuba each restored normal protrusion formation and spread to a bacterial strain deleted for the inlC gene (∆inlC). Dynamin 2 localized to apical junctions in uninfected human cells and protrusions in cells infected with L. monocytogenes. Localization of Dynamin 2 to junctions and protrusions depended on Tuba. Knockdown of Dynamin 2 or Tuba diminished junctional linearity, indicating a role for these proteins in controlling cortical tension. Infection with L. monocytogenes induced InlC-dependent displacement of Dynamin 2 from junctions, suggesting a possible mechanism of antagonism of this GTPase. Collectively, our results show that Dynamin 2 cooperates with Tuba to promote intercellular tension that restricts the spread of ∆inlC Listeria. By expressing InlC, wild-type L. monocytogenes overcomes this restriction.

Colorimetric aptasensor for Listeria monocytogenes detection using dual functional Fe3O4@MIL-100(Fe) with magnetic separation and oxidase-like activities in food samples.

A novel colorimetric aptasensor assay based on the excellent magnetic responsiveness and oxidase-like activity of Fe3O4@MIL-100(Fe) was developed. Fe3O4@MIL-100(Fe) absorbed with aptamer and blocked by BSA served as capture probe for selective isolation and enrichment of Listeria monocytogenes one of the most common and dangerous foodborne pathogenic bacteria. The aptamer absorbed on Fe3O4@MIL-100(Fe) was further used as signal probe that specifically binds with target bacteria conjugation of capture probe for colorimetric detection of Listeria monocytogenes, taking advantages of its oxidase-like activity. The linear range of the detection of Listeria monocytogenes was from 102 to 107 CFU mL-1, with the limit of detection as low as 14 CFU mL-1. The approach also showed good feasibility for detection of Listeria monocytogenes in milk and meat samples. The spiked recoveries were in the range 81-114% with relative standard deviations ranging from 1.28 to 5.19%. Thus, this work provides an efficient, convenient, and practical tool for selective isolation and colorimetric detection of Listeria monocytogenes in food.

Inactivation kinetics for surrogates of common foodborne pathogens during food residue drying.

Postconsumer household food residues can act as useful substrates for other industries, but transporting high-moisture material corresponds to high fuel use and associated greenhouse gas production. Drying food residues at the household level reduces transportation weight, increases stability, and preserves the nutritional quality of recovered material. Mitigating foodborne microbiological safety risks is crucial to encourage the development of novel methods to rapidly dry and stabilize food residues. The objective of this study was to improve the prediction of bacterial pathogen inactivation under various thermal and drying processes in a synthetic mixture of residual food material (RFM). The log reduction rate was measured for Escherichia coli, Enterococcus faecium, and Listeria innocua (surrogates of common foodborne pathogens) in RFM under different moisture contents (12% and 25% by fresh weight) and temperatures (50, 55, and 60°C). Inactivation data were used to determine D- and z-values and to fit a multiple regression model to predict log(D-values) in response to temperature and moisture content. Across conditions, D-values were measured to be 5.1-120, 4.6-123, and 32-545 min for E. coli, L. innocua, and E. faecium, respectively. Temperature sensitivities were significantly higher in lower moisture RFM for E. coli and L. innocua. Applying E. coli inactivation models during RFM at 55°C yielded inactivation rates that aligned with experimental values after 5 min (0.1 vs. 0-0.1 logs), 30 min (2.1 vs. 1.3-2.3 logs), and 90 min (7.2 vs. 7.1-8.9 logs). These results can inform the design of RFM drying and stabilization processes to promote pathogen inactivation and safety in downstream applications of dried material.

Interspecies Interaction of Bacteria Listeria monocytogenes, Yersinia pseudotuberculosis, and Marine Saprotrophs during Long-Term Culturing in Biofilms.

All bacterial strains studied retained the viability and ability to form both mono- and polycultural biofilms under conditions of long-term culturing in artificial seawater at 6°C and without addition of nutrients. Bacillus sp. and Pseudomonas japonica presumably stimulated the growth and reproduction of the pathogenic bacteria Listeria monocytogenes and Yersinia pseudotuberculosis. Preserved cell viability in a monoculture biofilm for a long period without adding a food source can indicate allolysis. At the same time, in a polycultural biofilm, the metabolites secreted by saprotrophic strains can stimulate the growth of L. monocytogenes and Y. pseudotuberculosis.

Assessing refrigerated preservation performance using Listeria predictive microbiology models and temperature data: Refrigerator performance indicator and time-temperature equivalent.

Time-temperature data for queso fresco (QF) cheese varieties stored in a residential refrigerator operating at 5°C and a predictive microbiology secondary model for Listeria monocytogenes in QF were used to estimate a refrigerator performance indicator (RPI) of microbial preservation. RPI values were used to assess how compressor technology (single [SS] and variable speed [VS]), ambient temperature (21.1°C [LT] and 32.2°C [HT]), and refrigerator load (22.5 kg regular load and 39 kg higher load) affected preservation performance. All deterministic and probabilistic RPI estimations slightly exceeded the desirable 1.0 value, i.e., the variable temperatures for the QF kept in the refrigerator were worse than keeping it constantly at the temperature recommended by food safety agencies for QF. Furthermore, the mean comparison of estimates of the time-temperature equivalent indicator previously developed by French researchers showed similar behavior to those observed for RPI. Finally, statistical analysis showed that Tambient was the factor with the highest impact on refrigerator performance because of its impact on the sample temperature increase during door openings and when exposed to ambient temperature during product use. This highlights the need to reduce the time for product temperature recovery by improving the compressor operation logic. Also important are consumer behavior changes such as a reduction in product exposure to ambient temperature and in the door opening duration and frequency. PRACTICAL APPLICATION: This study demonstrated how a quantitative tool (RPI) can assess refrigerator preservation performance. Although the findings presented can be applied to any cold chain segment, the data used was collected for its weakest link, the domestic refrigerator. Surveys show that 77% of them operate above the recommended 4°C. The RPI methodology is ready for use by refrigerator designers to assess performance improvements possible by modifications of the compressor operation logic. Moreover, it can be integrated into smart-hubs monitoring the frequency and duration of refrigerator door openings to inform consumers when their habits are compromising the preservation performance of the refrigerator.

Subinhibitory concentrations of glabridin from Glycyrrhiza glabra L. reduce Listeria monocytogenes motility and hemolytic activity but do not exhibit antimicrobial activity.

Increases in the virulence and survival of some pathogens in the presence of subinhibitory concentrations of antibiotics have been reported. However, research on the effects of subinhibitory concentrations of antimicrobial substances derived from traditional Chinese medicine on pathogens is still insufficient. Glabridin is a well-known active isoflavone found in licorice roots that possesses a wide range of biological activities. Therefore, in this study, Listeria monocytogenes (L. monocytogenes) exposed to subinhibitory concentrations of glabridin was used as the research object. The minimum inhibitory concentration (MIC) was determined for L. monocytogenes. We investigated the impacts of subinhibitory concentrations of glabridin on the morphology, motility, biofilm formation, adherence, and survival of L. monocytogenes. The results indicated that the MIC of glabridin for L. monocytogenes was 31.25 µg/mL. At 1/8, 1/4, or 1/2 of the MIC, glabridin did not affect the growth, morphology, flagellar production, or biofilm formation of L. monocytogenes. However, subinhibitory concentrations of glabridin inhibited bacterial swimming and swarming motility and decreased the hemolytic activity of L. monocytogenes. Glabridin reduced the hemolytic activity of L. monocytogenes culture supernatants. The results also showed that subinhibitory concentrations of glabridin had no toxic effect on RAW264.7 cells but decreased the intracellular growth of L. monocytogenes in RAW264.7 cells. Furthermore, subinhibitory concentrations of glabridin triggered ROS production but did not induce MET formation in macrophages. In addition, glabridin did not enhance the capacity of L. monocytogenes to trigger METs or the extracellular killing of macrophages by METs. Thus, we conclude that subinhibitory concentrations of glabridin reduce L. monocytogenes motility and hemolytic activity but do not exhibit antimicrobial activity. Glabridin could be an interesting food additive as a bacteriostatic agent with anti-Listeria activity.

Peritonitis caused by Listeria monocytogenes and Burkholderia cepacia in a patient on peritoneal dialysis: a case report.

Peritoneal dialysis (PD)-associated peritonitis is a major cause of peritoneal dysfunction and failure. The main issue regarding the treatment is whether to remove the catheter surgically or to treat with antibiotics alone. Notably, PD-associated peritonitis is commonly caused by gram-positive cocci, but rarely by Listeria monocytogenes and Burkholderia cepacia. Here, we report a patient diagnosed with PD-associated peritonitis caused by L. monocytogenes and B. cepacia who presented with a fever, abdominal pain, and turbid dialysate and had been receiving PD for over 20 years. After 2 weeks of antibiotic treatment, the catheter in the patient was surgically removed. Culture and pathology results revealed pathogen growth, foreign body granuloma with chronic inflammation, and inflammatory cells with fibroblast infiltration. The patient was switched to hemodialysis. She eventually recovered and was discharged. The patient presented fair health at the 3-month follow-up. In conclusion, sequential dialysate white blood cell count may help clinicians decide the course of treatment and guide the timing of surgical intervention.

Surveillance and genetic characterization of Listeria monocytogenes in the food chain in Montenegro during the period 2014-2022.

Introduction: Listeria monocytogenes is an ubiquitous foodborne pathogen that represents a serious threat to public health and the food industry. Methods: In this study Whole Genome Sequencing (WGS) was used to characterize 160 L. monocytogenes isolates obtained from 22,593 different food sources in Montenegro during the years 2014-2022. Results: Isolates belonged to 21 different clonal complexes (CCs), 22 sequence types (STs) and 73 core genome multilocus sequence types (cgMLST) revealing a high diversity. The most prevalent STs were ST8 (n = 29), ST9 (n = 31), ST121 (n = 19) and ST155 (n = 20). All isolates carried virulence genes (VGs), 111 isolates carried mobile genetic elements (MGEs) (ranging from 1 to 7 MGEs) and 101 isolates carried plasmids (ranging from 1 to 3 plasmids). All isolates carried the intrinsic resistance genes fosX and lin. None of the isolates carried acquired antimicrobial resistance genes (ARGs). Discussion/conclusion: Continuous monitoring and surveillance of L. monocytogenes is needed for improving and ameliorating the public health.

Growth, persistence and toxin production of pathogenic bacteria in plant-based drinking milk alternatives.

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

Impact of Liposomal Hesperetin in Broilers: Prospects for Improving Performance, Antioxidant Potential, Immunity, and Resistance against Listeria monocytogenes.

Liposomal encapsulated phytogenics, such as liposomal hesperetin, are considered novel substitutes for antibiotics in the broilers industry owing to their improved nutritional and therapeutic properties. Therefore, our key goal was to investigate liposomal hesperetin impact on broilers' growth performance, health, antioxidant status, tight junction proteins (TJP), and resistance against Listeria monocytogenes. Four broilers' groups were fed 0, 150, 250, and 400 mg/kg of liposomal hesperetin-supplemented diets and experimentally infected with L. monocytogenes strain. Herein, liposomal hesperetin, especially at higher concentrations, augmented broilers FCR with upregulation of genes encoding TJP (occludin, JAM-2, MUC-2), and antioxidant attributes (GPX-1, SOD-1, CAT, HO-1, NQO1, COX2), which reflect enhancing health and welfare of broilers. Muscle antioxidant biomarkers were enhanced; meanwhile, muscle MDA, ROS, and H2O2 levels were reduced in response to 400 mg/kg of liposomal hesperetin. Liposomal hesperetin fortification reduced L. monocytogenes loads and its virulence-related genes expression levels (flaA, hlyA, and ami). Remarkably, histopathological alterations in intestinal and brain tissues of L. monocytogenes infected broilers were restored post-inclusion at higher levels liposomal hesperetin, which reflects increasing the bird's resistance to L. monocytogenes infection. Transcription levels of genes encoding cytokines/chemokines (MyD88, AVBD6, CCL20, IL-1ß, IL-18), and autophagy (Bcl-2, LC3, AMPK, AKT, CHOP, Bip, p62, XBP1) were ameliorated following dietary liposomal hesperetin fortification, which suggests enhancing the birds' immunity and health. Collectively, our research recommends liposomal hesperetin application in broilers` diets owing to its promoting impact on growth performance, antioxidant status, immunity, health, and welfare besides its antibacterial, and antivirulence characteristics to fight against L. monocytogenes.

Relevance of microbiological cultures of cord blood and placental swabs in the rapid diagnosis of preterm newborn infection due to Listeria monocytogenes: A case report.

Listeria monocytogenes (Lm) is a Gram-positive bacterium causing listeriosis, a rare but severe foodborne infection, particularly impactful during pregnancy. Maternal-fetal transmission can lead to adverse fetal outcomes, yet symptoms in mothers may be nonspecific, delaying intervention. Despite the severity, the mechanisms of vertical transmission remain unclear. This report describes a case of rapid Lm diagnosis in a preterm newborn using cord blood and placental swabs. A 31-week pregnant woman presented with abdominal pain, diarrhea, and reduced fetal movements after consuming raw sushi. Laboratory findings indicated infection, and she vaginally delivered a live infant with placental and fetal abscesses. Cultures confirmed Lm, with swift diagnosis aided by molecular syndromic testing. The neonate received appropriate antibiotics and was asymptomatic by the end of treatment. This case underscores the need for the rapid diagnosis of maternal-fetal listeriosis, as it poses significant risks during pregnancy, including preterm birth and neonatal complications. Current diagnostic methods often delay treatment. This report emphasizes the use of innovative molecular techniques for early diagnosis, which is crucial in managing neonatal infections, especially in preterm newborns.

Antibacterial Mechanism of Garviecin LG34 Against S. Aureus and L. Monocytogenes and its Application in Milk Preservation.

The objective of this study was to reveal the antibacterial mode of action of garviecin LG34 against S. aureus CICC 21600 and L. monocytogenes CICC 21633 and measure the inhibitions on these two foodborne pathogenic bacteria in milk. Antibacterial mechanism of garviecin LG34 was ascertained by its effect on the efflux of Potassium (K+) ions, extracellular electrical conductivity, UV-absorbing substances, potential across the membrane (ΔΨ), and cell permeability. The inhibition of garviecin LG34 against S. aureus CICC 21600 and L. monocytogenes CICC 21600 in milk was studied by viable counting method. Supplementation with 160 AU/ml of garviecin LG34 had a bactericidal effect on S. aureus CICC 21600 and L. monocytogenes CICC 21633. A total of 80, 160, and 320 AU/ml of garviecin LG34 resulted in the effusion of potassium ion and UV-absorbing substances, the leakage of cellular electrolytes, and the dissipation of electrical potential across the membrane of these two food-borne bacteria and showed a dose-dependent. Moreover, the increase in cell permeability of both strains was observed by flow cytometer after cells treated with 160 AU/ml of garviecin LG34. Garviecin LG34 significantly inhibited the growth of these two food-borne bacteria in milk, especially in skimmed milk. Garviecin LG34 could cause pore formation, intracellular materials release, and permeability increase of S. aureus CICC 21600 and L. monocytogenes CICC 21633, and could be applied to milk as bio-preservative.

Single-Atom Au-Functionalized Mesoporous SnO2 Nanospheres for Ultrasensitive Detection of Listeria monocytogenes Biomarker at Low Temperatures.

Semiconductor metal oxide gas sensors have been proven to be capable of detecting Listeria monocytogenes, one kind of foodborne bacteria, through monitoring the characteristic gaseous metabolic product 3-hydroxy-2-butanone. However, the detection still faces challenges because the sensors need to work at high temperatures and output limited gas sensing performance. The present study focuses on the design of single-atom Au-functionalized mesoporous SnO2 nanospheres for the sensitive detection of ppb-level 3-hydroxy-2-butanone at low temperatures (50 °C). The fabricated sensors exhibit high sensitivity (291.5 ppm-1), excellent selectivity, short response time (10 s), and ultralow detection limit (10 ppb). The gas sensors exhibit exceptional efficacy in distinguishing L. monocytogenes from other bacterial strains (e.g., Escherichia coli). Additionally, wireless detection of 3-hydroxy-2-butanone vapor is successfully achieved through microelectromechanical systems sensors, enabling real-time monitoring of the biomarker 3-hydroxy-2-butanone. The superior sensing performance is ascribed to the mesoporous framework with accessible active Au-O-Sn sites in the uniform sensing layer consisting of single-atom Au-modified mesoporous SnO2 nanospheres, and such a feature facilitates the gas diffusion, adsorption, and catalytic conversion of 3-hydroxy-2-butanone molecules in the sensing layer, resulting in excellent sensing signal output at relatively low temperature that is favorable for developing low-energy-consumption gas sensors.

RIPS (rapid intuitive pathogen surveillance): a tool for surveillance of genome sequence data from foodborne bacterial pathogens.

Monitoring data submitted to the National Center for Biotechnology Information's Pathogen Detection whole-genome sequence database, which includes the foodborne bacterial pathogens Listeria monocytogenes, Salmonella enterica, and Escherichia coli, has proven effective for detecting emerging outbreaks. As part of the submission process, new sequence data are typed using a whole-genome multi-locus sequence typing scheme and clustered with sequences already in the database. Publicly available text files contain the results of these analyses. However, contextualizing and interpreting this information is complex. We present the Rapid Intuitive Pathogen Surveillance (RIPS) tool, which shows the results of the NCBI Rapid Reports, along with appropriate metadata, in a graphical, interactive dashboard. RIPS makes the information in the Rapid Reports useful for real-time surveillance of genome sequence databases.

Concomitant Listeria monocytogenes and Streptococcus equinus brain abscess in an immunocompetent individual: a case report.

BACKGROUND: Listeria monocytogenes brain abscess is a rare phenomenon that is common in immunocompromised patients. Streptococcus equinus brain abscess has never been reported in the literature to our knowledge. In this case report, we describe a case of brain abscess secondary to Listeria monocytogenes and Streptococcus equinus in an immunocompetent patient with transient low CD4 count. CASE PRESENTATION: A 27-year-old white, male patient, previously healthy, nonalcoholic, and occasional smoker, presented to the emergency department for confusion and headache. The patient was found to have a left parietal abscess, which was drained and the fluid was sent for culture. Culture grew Listeria monocytogenes and Streptococcus equinus. The patient was treated with intravenous ampicillin followed by oral amoxicillin for a total of 6 weeks. The CD4 count was low initially. However, after the resolution of the infection, the CD4 count came back within normal range. Another brain magnetic resonance imaging was done that showed a significantly decreased hyperintensity within the left parietal subcortical white matter at the site of surgery with significantly decreased enhancement and almost total resolution of the previous abscess. CONCLUSION: Transient low CD4 count is a rare phenomenon that exposes patients to unusual and atypical infections. Since low CD4 count is transient, patients treated promptly recover from their illness. Our patient developed a Listeria monocytogenes and Streptococcus equinus brain abscess, which is considered rare and has not been previously described in the literature to our knowledge.