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Listeria monocytogenes is an invasive opportunistic foodborne pathogen and its routine surveillance is critical for protecting the food supply and public health. The traditional detection methods are time-consuming and require trained personnel. Lateral flow immunoassay (LFIA), on the other hand, is an easy-to-perform, rapid point-of-care test and has been widely used as an inexpensive surveillance tool. In recent times, nucleic acid-based lateral flow immunoassays (NALFIA) are also developed to improve sensitivity and specificity. A significant improvement in lateral flow-based assays has been reported in recent years, especially the ligands (antibodies, nucleic acids, aptamers, bacteriophage), labeling molecules, and overall assay configurations to improve detection sensitivity, specificity, and automated interpretation of results. In most commercial applications, LFIA has been used with enriched food/environmental samples to ensure detection of live cells thus prolonging the assay time to 24-48 h; however, with the recent improvement in LFIA sensitivity, results can be obtained in less than 8 h with shortened and improved enrichment practices. Incorporation of surface-enhanced Raman spectroscopy and/or immunomagnetic separation could significantly improve LFIA sensitivity for near-real-time point-of-care detection of L. monocytogenes for food safety and public health applications.

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Listeria monocytogenes is one of the most invasive foodborne pathogens and is responsible for numerous outbreaks worldwide. Most of the methods to detect this bacterium in food require selective enrichment using traditional bacterial culture techniques that can be time-consuming and labour-intensive. Moreover, molecular methods are expensive and need specific technical knowledge. In contrast, immunological approaches are faster, simpler, and user-friendly alternatives and have been developed for the detection of L. monocytogenes in food, environmental, and clinical samples. These techniques are dependent on the constitutive expression of L. monocytogenes antigens and the specificity of the antibodies used. Here, updated knowledge on pathogenesis and the key immunogenic virulence determinants of L. monocytogenes that are used for the generation of monoclonal and polyclonal antibodies for the serological assay development are summarised. In addition, immunological approaches based on enzyme-linked immunosorbent assay, immunofluorescence, lateral flow immunochromatographic assays, and immunosensors with relevant improvements are highlighted. Though the sensitivity and specificity of the assays were improved significantly, methods still face many challenges that require further validation before use.

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Primary aortitis (PA) secondary to Listeria monocytogenes is extremely rare with only a few cases reported in the literature. Presently, there is no consensus concerning the best treatment when no complications are found in the thoracic computed tomography (CT) imaging. This report illustrates the clinical presentation and favorable clinical course of a rare case of PA secondary to Listeria monocytogenes in an 82-year-old diabetic woman, successfully treated with conservative management with 18 months of follow up. Included in this article, we additionally present a review of the literature of this uncommon etiology of infectious aortitis.

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Listeria is an unusual pathogen that causes neonatal infection with high morbidity and mortality. We present the case of a premature newborn whose mother had a rash during pregnancy; the newborn had severe early sepsis because of Listeria monocytogenes and histopathologically suggestive findings of the placenta. Obstetricians and neonatologists should suspect listeriosis in cases with compatible epidemiological history, clinical features, and examination findings of the placenta.

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Abstract Listeria is an unusual pathogen that causes neonatal infection with high morbidity and mortality. We present the case of a premature newborn whose mother had a rash during pregnancy; the newborn had severe early sepsis because of Listeria monocytogenes and histopathologically suggestive findings of the placenta. Obstetricians and neonatologists should suspect listeriosis in cases with compatible epidemiological history, clinical features, and examination findings of the placenta.

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Listeriosis is a sporadic infectious disease, which affects high-risk populations, such as the elderly, pregnant women, newborns, and immunocompromised patients. During pregnancy, listeriosis usually presents like a mild non-specific infection, but it may be responsible for fetal loss, preterm labor, early onset neonatal sepsis, and neonatal death. We report the case of a late stillbirth secondary to maternal chorioamnionitis. Listeria monocytogenes was isolated from the amniotic fluid and the fetal pleural fluid. The fetal autopsy revealed a disseminated inflammatory response with multi-organ involvement. This case illustrates the importance of the prevention and the diagnosis of listeriosis during gestation and may help us to understand the physiopathology of fetal loss due to listeriosis.

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Listeriosis is an uncommon but potentially serious infection caused by Listeria monocytogenes. The main route of transmission is through the consumption of contaminated food. It generally affects elderly people, pregnant women and immunosuppressed hosts, although cases are also seen in immunocompetent adults and children. Listeria monocytogenes is a short, anaerobic, non-spore-forming gram-positive bacillus that causes a narrow zone of hemolysis in blood agar. It is a facultative intracellular pathogen, and therefore it shows a complex pathogenesis. This bacterium has the ability to cross the intestinal barrier, the placenta and the blood-brain barrier producing gastroenteritis, maternal-fetal infections and meningoencephalitis. It is most commonly diagnosed from a positive culture of a sterile site. The treatment of choice includes the use of intravenous ampicillin alone or in combination with gentamicin.

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Resumen La listeriosis es una infección infrecuente pero potencialmente grave, causada por Listeria monocytogenes. La principal vía de transmisión es por el consumo de alimentos contaminados, afecta generalmente a personas mayores, mujeres embarazadas y hospederos inmunosuprimidos, aunque también se ven casos en adultos y niños inmunocompetentes. Listeria monocytogenes es un bacilo grampositivo corto, anaerobio facultativo, no formador de esporas, móvil, que provoca una zona angosta de hemólisis en agar sangre. Es un patógeno intracelular facultativo, por lo que presenta una compleja patogenia. Esta bacteria tiene la habilidad de atravesar la barrera intestinal, la placenta y la barrera hemato-encefálica produciendo cuadros de gastroenteritis, infecciones materno-fetales y meningoencefalitis. Se diagnostica, generalmente, a partir de un cultivo positivo de un sitio estéril. El tratamiento de elección incluye el uso de ampicilina intravenosa sola o en combinación con gentamicina.

Listeriosis is an uncommon but potentially serious infection caused by Listeria monocytogenes. The main route of transmission is through the consumption of contaminated food. It generally affects elderly people, pregnant women and immunosuppressed hosts, although cases are also seen in immunocompetent adults and children. Listeria monocytogenes is a short, anaerobic, non-spore-forming gram-positive bacillus that causes a narrow zone of hemolysis in blood agar. It is a facultative intracellular pathogen, and therefore it shows a complex pathogenesis. This bacterium has the ability to cross the intestinal barrier, the placenta and the blood-brain barrier producing gastroenteritis, maternal-fetal infections and meningoencephalitis. It is most commonly diagnosed from a positive culture of a sterile site. The treatment of choice includes the use of intravenous ampicillin alone or in combination with gentamicin.

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Background: Nitric oxide is synthesized from L-arginine and catalyzed by a family of NOS. There are three different NOS isoforms: neuronal (nNOS), inducible (iNOS) and endothelial (eNOS). Nitric oxide is an important apoptosis regulator in mammalian system that can induce and prevent apoptosis depending on levels of NO production and environmental conditions of the cell. NOS expression and its relationship with apoptosis has not been well elucidated in listerial meningoencephalitis in sheep. The aim of this study was to investigate eNOS and iNOS expressions in the brain of sheep with natural listeriosis and to compare them with apoptosis which is shaped in the region.Materials, Methods & Results: In the study, formalin fixed and paraffin embedded brainstem tissue from 25 sheep naturally infected with LM were used from archives. Five μm-thick section was taken from each block. Histopathologically, sections were stained with H&E. Five normal sheep brain tissues were used as control. At the end of the study, Histopathologically in brainstem tissue infected with LM, multifocal microabscesses in different sizes mixed with neutrophils and macrophages were detected and perivascular mononuclear cell infiltration and meningitis characterized by mononuclear cell infiltration were found. All sections were also immunohistochemically stained with LM, eNOS and iNOS antibodies. In addition, TUNEL method was used to determine apoptosis in brain tissues. As a result of immunostaining, listeria immunoreactivity was observed in microabscesses. The Listeria antigens were detected mainly in the cytoplasm of the neutrophils and macrophages and located extracellulary in microabscesses. Both eNOS and iNOS immunoreactivity were observed in very few neurons and glial cells in normal control sheep. Neurons and glial cells in brain tissues of infected animals stained with eNOS and iNOS.[...][(AU)

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Background: Nitric oxide is synthesized from L-arginine and catalyzed by a family of NOS. There are three different NOS isoforms: neuronal (nNOS), inducible (iNOS) and endothelial (eNOS). Nitric oxide is an important apoptosis regulator in mammalian system that can induce and prevent apoptosis depending on levels of NO production and environmental conditions of the cell. NOS expression and its relationship with apoptosis has not been well elucidated in listerial meningoencephalitis in sheep. The aim of this study was to investigate eNOS and iNOS expressions in the brain of sheep with natural listeriosis and to compare them with apoptosis which is shaped in the region.Materials, Methods & Results: In the study, formalin fixed and paraffin embedded brainstem tissue from 25 sheep naturally infected with LM were used from archives. Five μm-thick section was taken from each block. Histopathologically, sections were stained with H&E. Five normal sheep brain tissues were used as control. At the end of the study, Histopathologically in brainstem tissue infected with LM, multifocal microabscesses in different sizes mixed with neutrophils and macrophages were detected and perivascular mononuclear cell infiltration and meningitis characterized by mononuclear cell infiltration were found. All sections were also immunohistochemically stained with LM, eNOS and iNOS antibodies. In addition, TUNEL method was used to determine apoptosis in brain tissues. As a result of immunostaining, listeria immunoreactivity was observed in microabscesses. The Listeria antigens were detected mainly in the cytoplasm of the neutrophils and macrophages and located extracellulary in microabscesses. Both eNOS and iNOS immunoreactivity were observed in very few neurons and glial cells in normal control sheep. Neurons and glial cells in brain tissues of infected animals stained with eNOS and iNOS.[...][

Assuntos