Listeria monocytogenesy mecanismo de caballo de Troya a través de la barrera hematoencefálica / isteria monocytogenesand Trojan horse mechanism across the blood-brain barrier

Las infecciones del sistema nervioso central son potencialmente mortales, causadas por patógenos, como bacterias, virus y hongos. Para llegar hasta el cerebro, los microorganismos utilizan diversas vías y formas. Este patogeno es una bacteria grampositiva corta, flagelar e intracelular, con la capacidad de inducir su internalización en células fagocíticas (monocitos/macrófagos) y no fagocíticas (células endoteliales). Al infectar los macrófagos, estos microorganismos se valen de su capacidad de fijación, adhesión y migración transendotelial, para cruzar la barrera hematoencefálica, finalmente, generando meningitis bacteriana. En esta revisión describimos el mecanismo de caballo de Troya usado por Listeria monocytogenespara invadir el cerebro en el desarrollo de enfermedades infecciosas e incorporamos nuevos conocimientos sobre moléculas que intervienen en dicho mecanismo(AU)

Central nervous system infections are life-threatening, caused by pathogens such as bacteria, viruses and fungi. To access the brain, microorganisms use various mechanisms. Listeria monocytogenes is a short, flagellar and intracellular gram-positive bacterium, with the ability to induce its internalization in phagocytic (monocytes/macrophages) and non-phagocytic (endothelial cells) cells. By infecting macrophages, these microorganisms take advantage of their binding, adhesion, and transendothelial migrationcapacity to cross the blood-brain barrier, finally generating bacterial meningitis. In this review we describe the Trojan horse mechanism used by Listeria monocytogenesto invade the brain in the development of infectious diseases and we incorporate new knowledge about molecules that intervene in this mechanism(AU)

Meningitis por Listeria: serie de casos en un hospital de tercer nivel y utilidad de las nuevas técnicas de diagnóstico microbiológico / Listeria meningitis: case series in a tertiary level hospital and the usefulness of new microbiological diagnostic techniques

Introducción: La meningitis por Listeria monocytogenes (MLM) es una entidad grave con complicaciones a corto plazo. La reacción de polimerasa en cadena (RPC) puede ayudar a mejorar su diagnóstico y pronóstico. Objetivos: Conocer las características de los pacientes diagnosticados de meningitis por L. monocytogenes en los últimos años, a través de diferentes métodos microbiológicos. Pacientes y Métodos: Serie de casos de pacientes adultos ingresados con MLM en el Hospital Clínico San Carlos, Madrid, España, durante doce años (2009-2021). Se describieron variables epidemiológicas, clínicas, microbiológicas, radiológicas y terapéuticas. Resultados: Se registraron doce pacientes con MLM (edad media 67,5 años, 75% varones). En ocho se obtuvo un cultivo positivo a L. monocytogenes. La RPC en líquido cefalorraquídeo (LCR) fue positiva en los dos casos en los que se realizó la prueba. El tratamiento dirigido en todos los casos fue ampicilina durante 21 días. Se registraron complicaciones en un cuarto de los casos. Del total de pacientes uno falleció. Conclusiones: La MLM es una enfermedad poco frecuente y de difícil diagnóstico. En nuestra serie de casos los dos pacientes diagnosticados por RPC tuvieron resultado de cultivo de LCR negativo, y presentaron buena evolución. La determinación de RPC podría permitir diagnosticar un mayor número de casos y con mayor precocidad.

Background: Listeria monocytogenes meningitis (LMM) is a serious entity with short-term complications. Polymerase chain reaction (PCR) can help to improve its diagnosis and prognosis. Aim: To know the characteristics of patients diagnosed with meningitis by L. monocytogenes in recent years, through different microbiological methods. Methods: Case series of adult patients admitted with LMM at the Hospital Clínico San Carlos of Madrid, Spain, during twelve years (2009-2021). Epidemiological, clinical, microbiological, radiological and therapeutic variables were described. Results: Twelve patients with LMM were recorded (mean age 67.5 years, 75% male). Eight had a positive culture for L. monocytogenes. cerebrospinal fluid (CSF) PCR was positive in the two cases in which the test was performed. Treatment in all cases was ampicillin for 21 days. Complications were recorded in a quarter of the cases. One patient died. Conclusions: LMM is a rare and difficult to diagnose disease. In our series of cases, the two patients diagnosed by PCR had negative CSF culture results, and presented good evolution. PCR determination could allow a greater number of cases to be diagnosed earlier.

Antimicrobial activity of Tetradenia riparialeaf essential oil / Actividad antimicrobiana del aceite esencial de hoja de Tetradenia riparia

Food spoilage is a widely neglected problem and the constant use of synthetic fungicides could develop resistant fungi. The objective of this study was to evaluate the chemical composition and antimicrobial activity of Tetradenia riparialeaf essential oil against foodborne disease microorganisms. Leaf essential oil was obtained by hydrodistillation and identified by gas chromatography coupled to mass spectrometry. The antimicrobial activity was studied by broth microdilution. The major compounds identified were oxygenated sesquiterpenes (43.6%): 14-hydroxy-9-epi-(E)-cariophylene (20.8%) and τ-cadinol (18.4%); followed by oxygenated diterpenes (24.6%): 6,7-dehydroroyleanone (12.6%) and 9ß, 13ß-epoxy-7-abiethene (10.6%); sesquiterpenic hydrocarbons (17.1%) and oxygenated monoterpenes (7.4%): fenchone (5.6%). The essential oil had broad antibacterial and antifungal activity, mainly against A. versicolor and P. ochrochloron with fungistatic and fungicidal activities and B. cereus, L. monocytogenes, and S. aureuswith bacteriostatic and bactericidal activities. T. riparialeaf essential oil is a potential alternative to control microorganisms-

El deterioro de los alimentos es un problema ampliamente desatendido y el uso constante de fungicidas sintéticos podría desarrollar hongos resistentes. El objetivo de este estudio fue evaluar la composición química y la actividad antimicrobiana del aceite esencial de hoja de Tetradenia riparia contra microorganismos patógenos transmitidos por los alimentos. El aceite esencial de hoja se obtuvo por hidrodestilación y se identificó mediante cromatografía de gases acoplada a espectrometría de masas. La actividad antimicrobiana estudiada fue por microdilución en caldo. Los compuestos principales del aceite esencial se identificaron como sesquiterpenos oxigenados (43,6%): 14-hidroxi-9-epi-(E)-cariofileno (20,8%) y τ-cadinol (18,4%); seguido de diterpenos oxigenados (24,6%): 6-7-deshidroroileanona (12,6%) y 9ß, 13ß-epoxi-7-abieteno (10,6%); hidrocarburos sesquiterpénicos (17,1%) y monoterpenos oxigenados (7,4%): fenchona (5,6%). Tenía amplia actividad antibacteriana y antifúngica, principalmente contra A. versicolor y P. ochrochloron con actividades fungistáticas y fungicidas, y principalmente contra B. cereus, L. monocytogenes y S. aureus con actividades bacteriostáticas y bactericidas. El aceite esencial de hoja de T. riparia es una alternativa potencial para controlar microorganismos.

IL-17B regulates Listeria monocytogenes infection by inhibiting macrophage infiltration / 中华微生物学和免疫学杂志

Objective:To investigate the related mechanism of IL-17B in regulating host immune response by studying the role and mechanism of IL-17B in the infection of Listeria monocytogenes in mice. Methods:Eighteen male C57BL/6 mice were randomly divided into three groups with six in each group: control group, PBS group and wild-type (WT) group. The control group was not given any treatment. The mice in the PBS group were injected with 100 μl of sterile PBS, while C57BL/6 mice in the WT group and IL-17B deficient (IL-17B -/-) male mice were injected intravenously with 100 μl of Listeria monocytogenes 19115 (2×10 4 colony forming unit). The mice were sacrificed 48 h after infection and then peripheral blood, spleen and liver samples were collected. Bacterial colonization in mouse spleen and liver was detected by plate count method; HE staining was used to evaluate histopathological damages; flow cytometry was used to detect the immune cells in different tissues. ELISA and qRT-PCR were used to detect the levels of IL-1β, IL-6, IL-12p40, TNF-α, IFN-γ and iNOS in serum and spleen. qRT-PCR were used to detect the expression of IL-17B and IL-17RB. Results:Bacterial colonization in mouse spleen was reduced in the IL-17B -/- group as compared with that in the WT group ( P<0.05). Compared with the PBS group, Listeria monocytogenes infection increased the expression of IL-17B and IL-17RB in mouse spleen ( P<0.05, P<0.01). There was no significant difference in the pathological damages in spleen between WT and IL-17B -/- groups. Moreover, compared with the WT group, the IL-17B -/- group showed increased macrophages, M1 macrophages ( P<0.01) and NK cells ( P<0.05) in spleen, up-regulated macrophages ( P<0.05) and M1 macrophages ( P<0.01) in the peripheral blood, enhanced expression of IL-6 in serum and spleen ( P<0.05), and promoted expression of IL-6, IL-12, IL-1β, TNF-α, IFN-γ and iNOS in spleen. Conclusions:IL-17B might inhibit Listeria monocytogenes clearance by inhibiting macrophage infiltration and the secretion of IL-6.

Advances in in vitro and in vivo models for Listeria monocytogenes placental infection / 生物工程学报

Listeria monocytogenes is recognized as a significant foodborne pathogen, capable of causing listeriosis in humans, which is a global public health concern. This pathogen is particularly dangerous for pregnant women, as it can lead to invasive listeriosis in fetuses and neonates, posing a significant threat to both maternal and fetal health. Therefore, establishing suitable in vitro and in vivo models for L. monocytogenes placenta infection, as well as analyzing and exploring the infection process and its pathogenic mechanism, are important approaches to prevent and control L. monocytogenes infection in mothers and infants. In this study, we reviewed the in vitro and in vivo placental models used for studying the infection of L. monocytogenes in maternal and infant, summarized and discussed the advantages and limitations of each model, and explored the potential of in vitro cell models and organoids for the study of L. monocytogenes infection. This paper aims to support the study of the infection pathway and pathogenesis of listeriosis and provide scientific references for the prevention and control of L. monocytogenes infection.

Analysis of 50 cases of bloodstream infection with Listeria monocytogenes / 中国热带医学

@#Abstract: Objective　To analyze the characteristics of bloodstream infection of Listeria monocytogenes and provide basis for the diagnosis and treatment of the disease. Methods　We retrospectively analyzed the cases of Listeria monomyrhosi bloodstream infection in Peking Union Medical College Hospital (PUMCH) from April 2012 to April 2022. The age, sex, onset time, underlying disease, symptoms, diagnosis, treatment and prognosis of the patients were analyzed, as well as the changes of white blood cells (WBC), neutrophils, lymphocytes, and C-reactive protein (CRP) before and after anti-infection treatment. Results　Fifty cases of Listeria monocytogenes bloodstream infection confirmed by blood culture were involved. The age of patients ranged from 0 to 82 (43.7±20.0) years old, among whom 20.0% were over 60 years old. The onset time of patients was the highest in spring (44.0%), followed by winter (24.0%), and relatively fewer in summer and autumn (14.0%-18.0%). The median diagnosis time was 3 days (1-60 days). After the etiological diagnosis, 45 patients (90.0%) had underlying diseases or pregnancy status, and 45 patients were adjusted to the target antibacterial treatment mainly with carbapenems (48.9%) and penicillins (44.4%). The level of WBC, neutrophils, lymphocytes, monocytes, and CRP after treatment were significantly lower than those pre-treatments (P<0.05). Among all patients, 36 cases (72.0%) were treated according to the Antimicrobial Treatment Guidelines for Fever Sanford, of which 26 cases (72.2%) were discharged from the hospital, two cases died, one case was transferred to other hospitals, and 7 cases had a poor prognosis. Conclusions　Autoimmune diseases, tumor diseases, pregnant patients are susceptible to Listeria monocytogenes infection. Penicillins are the first choice for effective empiric therapy. For the patients allergic to penicillins, trimethoprim/sulfamethoxazole or meropenem could be used.

Listeriosis diseminada: a propósito de un caso

La listeriosis es una enfermedad infecto contagiosa, transmitida por los alimentos, prevenible, y potencialmente grave. Las formas clínicas de presentación pueden ser muy variadas, desde una gastroenterocolitis hasta sepsis grave y compromiso multisistémico. Se discute el caso de una mujer joven que se presenta con manifestaciones neuropsiquiátricas y sistémicas subagudas, en contexto febril en la que a través de hemocultivos se llega al diagnóstico de Listeriosis invasiva. Se destaca el compromiso profundo parenquimatoso a forma de abscesos múltiples, como presentación menos frecuente. Se realiza tratamiento médico, antibioticoterapia prolongada, con franca mejoría clínica imagenológica. El diagnóstico de esta enfermedad requiere un alto índice de sospecha, optimizar las herramientas diagnósticas para un correcto relevo bacteriológico y así poder instaurar precozmente la antibioticoterapia.

Listeriosis is an infectious, contagious, foodborne, preventable, and potentially serious disease. The clinical forms of presentation can be very varied, from gastroenterocolitis to severe sepsis and multisystem involvement. We discuss the case of a young woman with subacute neuropsychiatric and systemic manifestations, in a febrile context in which the diagnosis of invasive Listeriosis is reached through blood cultures. Deep parenchymal involvement in the form of multiple abscesses stands out as a less frequent presentation. Medical treatment, prolonged antibiotic therapy, with clear clinical imaging improvement is performed. The diagnosis of this disease requires a high index of suspicion, optimization of diagnostic tools for a correct bacteriological relief and thus early initiation of antibiotic therapy.

A listeriose é uma doença infecciosa, contagiosa, transmitida por alimentos, evitável e potencialmente grave. As formas clínicas de apresentação podem ser muito variadas, desde gastroenterocolite até sepse grave e envolvimento multissistêmico. Discutimos o caso de uma jovem que apresenta manifestações neuropsiquiátricas e sistêmicas subagudas, em um contexto febril em que o diagnóstico de Listeriose invasiva é alcançado por meio de hemoculturas. O envolvimento do parênquima profundo na forma de múltiplos abscessos destaca-se como uma apresentação menos frequente. Realiza-se tratamento médico, antibioticoterapia prolongada, com nítida melhora da imagem clínica. O diagnóstico desta doença requer um alto índice de suspeição, otimização das ferramentas diagnósticas para um correto alívio bacteriológico e, assim, início precoce da antibioticoterapia.

Actividad antibacterial de nanopartículas de óxido de zinc sobre Listeria monocytogenes ATCC 7644 / Antibacterial activity of zinc oxide nanoparticles against Listeria monocytogenes ATCC 7644

Introducción: Las nanopartículas de óxido de zinc (Np-ZnO) presentan diferentes comportamientos; permitiendo su aplicación en diversas áreas. Objetivos: Determinar cuál es la concentración mínima inhibitoria de nanopartículas de óxido de zinc sobre el crecimiento de Listeria monocytogenes ATCC 7644. El estudio: Se utilizaron nanopartículas de ZnO con un tamaño promedio de 90 nm, a diferentes concentraciones de 4; 2; 1; 0,5; 0,25; 0,12; 0,06; 0,03; 0,01; 0,007 mg/mL de Np-ZnO, preparadas en solución acuosa. Se incubó en un tiempo correspondiente al de generación de la bacteria, evaluando el crecimiento con la aparición de turbidez. Hallazgos: Listeria monocytogenes ATCC 7644 presentó una CMI de 0,06 mg/mL. Conclusión: La concentración mínima inhibitoria (CMI) resultante para las nanopartículas de óxido de zinc (Np-ZnO) de 90 nm de tamaño promedio fue de 0,06 mg/mL, suficiente para controlar significativamente el crecimiento contra Listeria monocytogenes ATCC 7644.

background:Zinc oxide nanoparticles (Np-ZnO) have different behaviors which allows its application in various areas. : To determine the Objectivesminimum inhibitory concentration (MIC) of Zinc oxide nanoparticles for Listeria monocytogenes ATCC 7644. Zinc oxide nanoparticles with an The study:average size of 90nm and different concentrations of 4; 2; 1; 0,5; 0,25; 0,12; 0,06; 0,03; 0,01; 0,007 mg/mLprepared in aqueous solution were used. It was incubated at a time corresponding to generation time of the bacteria, evaluating the growth with the presence of turbidity. : The MIC for FindingsListeriamonocytogenesATCC7644was0,06mg/mL.The Conclusion:minimum inhibitory concentration (MIC) of Zinc oxide nanoparticles (Np-ZnO) with an average size of 90nm for Listeria monocytogenes ATCC 7644 was 0,06 mg/mL, enough value to significantly control the growth of for Listeria monocytogenes ATCC 7644.

Genotyping of Listeria monocytogenes isolates by high-resolution melting curve (HRM) analysis of tandem repeat locus

Abstract Listeria monocytogenes is responsible for causing listeriosis, a type of food poisoning with high mortality. This bacterium is mainly transmitted to humans through the consumption of contaminated foods. Detection of L. monocytogenes through molecular methods is crucial for food safety and clinical diagnosis. Present techniques are characterized by low discrimination power and high cost, as well as being time-consuming and taking several days to give the final result. In our study, MLVA-HRM (Multiple-Locus Variable-number tandem repeats Analysis ‒ High-Resolution Melting) was investigated as an alternative method for a fast and precise method for the genotyping of L. monocytogenes isolates. Forty-eight isolates of L. monocytogenes obtained from the microbial bank of Department of Microbiology, Iran University of Medical Sciences, were typed by MLVA-HRM analysis using five Variable Numbers of Tandem Repeat (VNTR) loci. A total of 43 different types were obtained. This research demonstrated the usefulness of the MLVA-HRMA method and its ability to discriminate L. monocytogenes isolates. Since this method is easier and more efficient than existing methods, it can be widely used in food processing plants and diagnostic laboratories as a fast and accurate method.

Cobalamin cbiP mutant shows decreased tolerance to low temperature and copper stress in Listeria monocytogenes

BACKGROUND: Listeria monocytogenes is a foodborne pathogen that causes listeriosis in humans. This pathogen activates multiple regulatory mechanisms in response to stress, and cobalamin biosynthesis might have a potential role in bacterial protection. Low temperature is a strategy used in the food industry to control bacteria proliferation; however, L. monocytogenes can grow in cold temperatures and overcome different stress conditions. In this study we selected L. monocytogenes List2-2, a strain with high tolerance to the combination of low temperature +copper, to understand whether the cobalamin biosynthesis pathway is part of the tolerance mechanism to this stress condition. For this, we characterized the transcription level of three cobalamin biosynthesis related genes ( cbiP , cbiB, and cysG ) and the eutV gene, a transcriptional regulator encoding gene involved in ethanolamine metabolism, in L. monocytogenes strain List2-2 growing simultaneously under two environmental stressors: low temperature (8 °C) +copper (0.5 mM of CuSO4 ×5H2O). In addition, the gene cbiP , which encodes an essential cobyric acid synthase required in the cobalamin pathway, was deleted by homologous recombination to evaluate the impact of this gene in L. monocytogenes tolerance to a low temperature (8 °C) +different copper concentrations. RESULTS: By analyzing the KEGG pathway database, twenty-two genes were involved in the cobalamin biosynthesis pathway in L. monocytogenes List2-2. The expression of genes cbiP , cbiB, and cysG, and eutV increased 6 h after the exposure to low temperature +copper. The cobalamin cbiP mutant strain List2-2Δ cbiP showed less tolerance to low temperature +copper (3 mM) than the wild type L. monocytogenes List2-2. The addition of cyanocobalamin (5 nM) to the medium reverted the phenotype observed in List2-2Δ cbiP . CONCLUSION: These results indicate that cobalamin biosynthesis is necessary for L. monocytogenes growth under stress and that the cbiP gene may play a role in the survival and growth of L. monocytogenes List2-2 at low temperature +copper.

Distribución y caracterización fenotípica y genotípica de Listeria monocytogenes en aislamientos de alimentos, Colombia, 2010-2018 / Distribution and phenotypic and genotypic characterization of Listeria monocytogenes isolated from food, Colombia, 2010-2018

Resumen | Introducción. Listeria monocytogenes es un patógeno transmitido por alimentos que causa infecciones en humanos, entre ellas, meningitis, meningoencefalitis y septicemias, así como abortos. Con la tipificación serológica se han identificado 13 serotipos, siendo el 4b el causante de la mayoría de los brotes en el mundo. Objetivo. Determinar la frecuencia y la distribución de los serotipos y subtipos moleculares de L. monocytogenes aislados de alimentos en Colombia entre el 2010 y el 2018. Materiales y métodos. Se hizo un estudio descriptivo y retrospectivo a partir del análisis de 2.420 aislamientos que fueron identificados como L. monocytogenes y otras especies, por medio de pruebas bioquímicas, serológicas y de subtipificación molecular mediante electroforesis en gel de campo pulsado (PFGE). Resultados. De los 2.420 aislamientos recibidos, 2.326 fueron confirmados como L. monocytogenes. Los serotipos encontrados fueron: 4b (52%), 4d-4e (14,5%), 1/2a (11%), 1/2c (9,4%), 1/2b (9 %), y 3a, 3b, 3c, 4c, 4d, 4e y 7 (menos de 2%). Procedían de Bogotá (43%), Antioquia (25%), Valle (10%), Nariño (9%) y otros departamentos (7%). La caracterización genotípica agrupó los aislamientos evaluados en 167 patrones de PFGE; los perfiles más frecuentes se presentaron en productos lácteos, cárnicos y alimentos preparados. Conclusión. El 96,1 % de los aislamientos correspondieron a L. monocytogenes, con una buena concordancia entre el aislamiento y la identificación; el serotipo 4b, extremadamente virulento, fue el más frecuente. El análisis molecular evidenció la posible diseminación y permanencia en el tiempo de varios serotipos, lo que resalta la importancia de incluir este patógeno en los programas de vigilancia epidemiológica en alimentos.

Abstract | Introduction: Listeria monocytogenes is a food-borne pathogen that may cause infections in humans such as meningitis, meningoencephalitis, and septicemia, as well as abortions. By serological typing 13 serotypes have been identified of which 4b is responsible for most of the outbreaks in the world. Objective: To determine the frequency and distribution of serotypes and molecular subtypes of L. monocytogenes isolated in Colombia from food from 2010 to 2018. Materials and methods: We conducted a retrospective and descriptive study based on the analysis of 2,420 isolates confirmed as L. monocytogenes and other species using biochemical and serological tests, and pulsed-field gel electrophoresis (PFGE) for molecular subtyping. Results: Of the 2,420 isolates received, 2,326 were confirmed as L. monocytogenes. The serotypes found were 4b (52%), 4d-4e (14.5%), 1/2a (11%), 1/2c (9.4%), 1/2b (9%), and 3a, 3b, 3c, 4c, 4d, 4e and 7 (less than 2%). The isolates came from Bogotá (43%), Antioquia (25%), Valle (10%), Nariño (9%), and other departments (7%). The genotypic characterization grouped the isolates in 167 PFGE patterns. The most frequent patterns were identified in various dairy and meat products, and in prepared foods. Conclusion: A 96.1% of the isolates corresponded to L. monocytogenes showing good agreement between isolates and identification. Serotype 4b, highly virulent, was the most frequent. The molecular analysis showed the possible dissemination and permanence over time of several serotypes, which highlights the importance of including this pathogen in epidemiological food surveillance programs.

Muerte perinatal por listeriosis

Mujer de 35 años, con 22 semanas de gestación, presentó fiebre sin origen determinado y disminución de los movimientos fetales, evolucionando con muerte fetal por infección por Listeria monocytogenes, evidenciada por hemocultivos y el estudio anatomo- patológico del feto y la placenta.

Caracterización de bacterias ácido lácticas con actividad antimicrobiana aisladas del queso crema de Chiapas, México / Characterization of lactic acid bacteria with antimicrobial activity isolated from cream cheese from Chiapas, Mexico

Resumen El queso crema de Chiapas es un producto artesanal fabricado en diferentes regiones de México. La capacidad de las bacterias lácticas, de producir grandes cantidades de ácido láctico y acético, tiene como efecto la disminución del pH, considerado uno de los factores primarios en la inhibición de microorganismos indeseables, como patógenos y bacterias coliformes, en alimentos lácteos. El objetivo de este trabajo fue aislar bacterias ácido lácticas y evaluar su efecto antagónico contra bacterias patógenas in vitro y contra patógenos presentes en la leche cuando se adicionan durante la elaboración del queso crema. Se aislaron cepas de bacterias lácticas del queso crema de Chiapas, México. Los aislados fueron identificados mediante pruebas bioquímicas API 50CH y secuencias del gen ribosomal 16S. Las bacterias de interés se usaron en pruebas de inhibición del crecimiento con cepas patógenas. Se cuantificó la producción de ácido acético y láctico por cromatografía de gases acoplado a masas en los quesos, al inicio y a los 10 d posteriores a su elabo ración. Se aislaron 203 cepas bacterianas, de las cuales 82 tuvieron la capacidad de inhibir el crecimiento de 7 cepas bacterianas patógenas. Las cepas fueron identificadas por la secuencia parcial del gen ribosomal 16S como pertenecientes al género Lactobacillus; la adición de estas cepas en la elaboración del queso crema redujo o eliminó coliformes, Staphylococcus aureus, mohos y levaduras, mientras que en el queso elaborado con leche pasteurizada se detectaron 290 UFC/mL de mohos y levaduras. Estos resultados sugieren que las cepas de Lactobacillus aisladas del queso crema artesanal de Chiapas tienen potencial para su uso como cultivo iniciador con actividad de bioconservación en este y productos similares.

Abstract Chiapas cream cheese is an artisanal product manufactured in different regions of Mexico. The ability of lactic bacteria to produce large amounts of lactic and acetic acid has the effect of decreasing the pH, considered one of the primary factors in the inhibition of undesirable microorganisms such as pathogens and coliform bacteria, in dairy foods. The objective of this work was to isolate lactic acid bacteria and evaluate their antagonistic effect against pathogenic bacteria in vitro, as well as their effect against pathogens that are present in milk when they are added in the preparation of cream cheese. Strains of lactic bacteria were isolated from cream cheese from Chiapas, Mexico. Isolates were identified by API 50CH biochemical tests and 16S ribosomal gene sequences. The bacteria under study were used in pathogen growth inhibition tests. The production of acetic and lactic acid was quantified by gas chromatography coupled to masses in the cheeses at the beginning and 10 d after its elaboration. 203 bacterial strains were isolated, 82 of which had the ability to inhibit the growth of 7 pathogenic bacterial strains. The strains were identified by the partial sequence of the 16S ribosomal gene as belonging to the genus Lactobacillus; The addition of these strains in the elaboration of cream cheese reduces or eliminates coliforms, Staphylococcus aureus, molds and yeasts, while in the cheese made with pasteurized milk 290 CFU/mL of molds and yeasts were detected. These results suggest that Lactobacillus strains isolated from Chiapas artisanal cream cheese has the potential to be used as a starter culture with bioconservation activity in this and similar products.

Infección por listeria monocytogenes en el embarazo, asociado a desprendimiento de placenta y complicaciones perinatales: reporte de un caso / Listeria monocytogenes infection in pregnancy, associated with placental abruption and perinatal complications: case report

INTRODUCCIÓN la listeriosis, aunque es una infección infrecuente, debe ser considerada en pacientes inmunocomprometidos y gestantes, especialmente en aquellos que consumen alimentos crudos o productos lácteos no pasteurizados, lo que pone en riesgo a un gran número de mujeres embarazadas en países de habla hispana. Es importante que el médico considere su inclusión en los posibles diagnósticos diferenciales cuando la sospecha clínica lo amerite, lo que permitirá hacer un diagnóstico temprano y por lo tanto un tratamiento oportuno, evitando así las posibles complicaciones en el binomio madre-hijo. CASO CLÍNICO clínico multigestante, con embarazo de 33 + 5 semanas, que ingresó a una institución de alto nivel de complejidad en la ciudad de Medellín, Colombia, por síndrome febril asociado a sepsis obstétrica debido a infección intraamniótica por Listeria monocytogenes, que requirió cesárea de urgencia, en donde se evidenció un desprendimiento placentario del 100 % secundario al proceso infeccioso y asociado a complicaciones neonatales. CONCLUSIONES: el diagnóstico de listeriosis gestacional supone un reto clínico por su presentación inespecífica y baja incidencia. Sin embargo, las consecuencias obstétricas arrastran una gran morbilidad de la madre y morbi-mortalidad neonatal, lo que hace de suma importancia que el clínico lo tenga presente en su arsenal diagnóstico, ya que una vez diagnosticado, el tratamiento oportuno tiene desenlaces clínicos favorables.

INTRODUCTION: although listeriosis is a rare infection, it should be considered in immunocompromised patients and pregnancy, especially in those who consume raw food or unpasteurized dairy, which puts a large number of pregnant women in Hispanic countries at risk. It is of special importance for physicians to include listeriosis among possible diagnoses when clinical suspicion arises in order to timely treat it and thus avoid the complications that may occur in the mother-child binomial. CLINICAL CASE: a pregnant woman (33 + 5 weeks) with multiple gestations, was admitted to a high level of complexity institution in the city of Medellín, Colombia, presenting a febrile syndrome associated with obstetric sepsis due to intra-amniotic infection by Listeria monocytogenes, which required emergency cesarean section where a 100 % placental abruption was evidenced secondary to the infectious process and associated with neonatal complications. CONCLUSIONS: The diagnosis of gestational listeriosis is a clinical challenge due to its nonspecific presentation and low incidence. However, the obstetric consequences drag a great maternal morbidity and neonatal morbidity and mortality, which is why it is important for physicians to consider this in the diagnostic arsenal because once diagnosed, the appropriate treatment has favorable clinical outcomes.

Listeriose em pacientes nefropatas imunossuprimidos - relato de dois casos / Listeriosis in patients immunosuppressed nephropaths - report of two cases

Contexto: A Listeria monocytogenes é um bacilo gram-positivo de baixa patogenicidade na população geral, mas importante causa de mortalidade por sepse e meningite em pacientes imunocomprometidos. Receptores de órgãos sólidos e candidatos em tratamento de dessensibilização são suscetíveis à infecção pela Listeria monocytogenes, embora sua apresentação clínica seja pouco reconhecida. Descrição dos casos: Paciente do sexo masculino, 43 anos, internado devido a rejeição aguda de enxerto pós-transplante renal, apresenta pico febril matutino e cefaleia. Paciente do sexo feminino, 59 anos, com doença renal crônica e em terapia de dessensibilização devido reatividade a painel antígeno leucocitário humano, busca pronto-socorro com febre, cefaleia e diarreia. A infecção por Listeria monocytogenes foi confirmada por hemocultura em ambos os casos. Discussão: A ocorrência de listeriose é esporádica e associada ao consumo de alimentos altamente contaminados, como laticínios, produtos frescos e carnes processadas. A redução da imunocompetência é o principal fator de risco para o desenvolvimento da doença em não gestantes, bem como para o aumento da mortalidade. O diagnóstico é estabelecido majoritariamente por hemocultura e o exame do líquido cefalorraquidiano é imprescindível para acessar o acometimento do sistema nervoso central, uma vez que os sinais meníngeos podem estar ausentes. O tratamento é realizado com beta-lactâmicos ou aminoglicosídeos. A ampicilina foi utilizada nos casos relatados e promoveu boa resposta clínica. Conclusão: Os profissionais devem atentar para a gravidade da infecção por Listeria monocytogenes e considerar sua ocorrência em pacientes imunocomprometidos, fornecendo orientações profiláticas a todos os candidatos a transplante de órgãos sólidos e tratamento empírico nos casos suspeitos.

Chemical characterization and antimicrobial activity of Campomanesia aurea against three strains of Listeria monocytogenes / Caracterização química e atividade antimicrobiana de Campomanesia aurea contra três cepas de Listeria monocytogenes

Abstract The essential oil (EO) composition of leaves of Campomanesia aurea was analyzed by GC-MS. The plant was collected in April (EOA) and October (EOO) in São Francisco de Assis/RS. The essential oils were obtained by hydrodistillation in a modified Clevenger apparatus. The yields were 4.44% in April, and 6.15%, in October. Thirty-one compounds were identified in EOA, accounting for 96.87% of the total, and twenty-eight compounds were identified in EOO, accounting for 99.46% of the total. For EOA, the major identified monoterpene was p-cymene (8.33%) and the major identified sesquiterpene was α-cadinol (10.72%), while regarding EOO the major identified monoterpene was repeatedly Terpinolene (3.43%), whereas the major identified sesquiterpene was α-cadinol (12.79%). The antibacterial activity of the essential oil was evaluated against the three Listeria monocytogenes from the American Type Culture Collection (strains ATCC 7644, 19114 and 13932). The essential oil showed a MIC of 10 mg/mL against the strains ATCC 7644 and 19114, with bacteriostatic effect of 20 mg/mL and a MIC of 20 mg/mL for ATCC 13932. Regarding the antibiofilm activity, o EOO showed the best results with an inhibition of 90% in the sessile growth with an applied concentration of 4.0 mg/mL.

Resumo O óleo essencial (EO) das folhas de Campomanesia aurea foi analisado por CG-EM. O A planta foi coletada em abril (OEA) e outubro (OEO) em São Francisco de Assis/RS. Os óleos essenciais foram obtidos por hidrodestilação em aparelho Clevenger modificado. Os rendimentos foram de 4,44% em abril e 6,15% em outubro. Trinta e um compostos foram identificados no EOA, representando 96,87% do total, e vinte e oito compostos foram identificados no EOO, representando 99,46% do total. Para EOA, o principal monoterpeno identificado foi o p-cimeno (8,33%) e o principal sesquiterpeno identificado foi o α-candinol (10,72%), enquanto o EOO o maior monoterpeno identificado foi repetidamente Terpinolene (3,43%), enquanto o sesquiterpeno principal identificado foi α-cadinol (12,79%). A atividade antibacteriana do óleo essencial foi avaliada contra as três cepas de Listeria monocytogenes obtidas a partir da American Type Culture Collection (isolados ATCC 7644, 19114 and 13932). O óleo essencial apresentou uma CIM de 10 mg/mL contra as cepas ATCC 7644. e 19114, com efeito bacteriostático de 20 mg/mL e MIC de 20 mg/mL para ATCC 13932. Quanto à atividade antibiofilme, o EOO apresentou os melhores resultados com uma inibição de 90% no crescimento séssil com uma concentração aplicada de 4,0 mg/mL.

Bacteriemia por listeria en pacientes de un instituto oncológico peruano, 2005-2015 / Listeria bacteremia in patients from a peruvian oncologic institute, 2005-2015

RESUMEN La listeriosis es una infección severa de elevada morbimortalidad en el paciente inmunocomprometido, existen formas diseminadas y fatales en el paciente oncológico. Se realizó un estudio descriptivo de las características clínico-epidemiológicas de los pacientes oncológicos con listeriosis atendidos en el Instituto Nacional de Enfermedades Neoplásicas entre 2005 y 2015. Se incluyeron 29 pacientes, 23 (79,3%) casos de listeriosis se presentaron en pacientes con neoplasia hematológica, de los cuales el 52,3% fueron leucemia linfática aguda y 39,1% linfoma no Hodgkin. Listeria monocytogenes representó el 72,4% de las especies aisladas. Veintisiete (93,1%) tuvieron criterios de sepsis y veinticuatro (82,7%) compromiso neurológico al ingreso. La presentación más común fue la bacteriemia, seguida de la meningoencefalitis (20,6%). La mortalidad global fue del 75,8%. Se concluye que la listeriosis conlleva elevada morbimortalidad en el paciente oncohematológico, por lo que debe sospecharse en el paciente admitido con sepsis y/o compromiso neurológico agudo.

ABSTRACT Listeriosis infection is a severe disease, with high morbidity and mortality in the immunocompromised patient, especially with disseminated and fatal presentations in cancer patients. A descriptive study was developed to describe the clinical and epidemiologic characteristics in oncologic patients with listeriosis in the Instituto Nacional de Enfermedades Neoplásicas between the years 2005-2015. A total of 29 patients were included; 23 (79.3%) of the listeriosis cases showed up in patients with hematological neoplasia, of which 52.1% was acute lymphatic leukemia and 39.1% non-Hodgkin's lymphoma. The 72.4% of the isolated species correspond to Listeria monocytogenes. Twenty-seven (93.1%) patients met sepsis criteria and twenty-four (82.7%) had neurologic affection. Bacteremia was the most common presentation, followed by meningoencephalitis (20.6%). Global mortality was 75.8%. In conclusion in cancer patients, listeriosis implies high morbidity and mortality. Therefore, the suspicion of this entity is mandatory in onco-hematologic patients with sepsis and acute neurologic symptoms.

Bacteriemia por listeria en pacientes de un instituto oncológico peruano, 2005-2015 / Listeria bacteremia in patients from a peruvian oncologic institute, 2005-2015

RESUMEN La listeriosis es una infección severa de elevada morbimortalidad en el paciente inmunocomprometido, existen formas diseminadas y fatales en el paciente oncológico. Se realizó un estudio descriptivo de las características clínico-epidemiológicas de los pacientes oncológicos con listeriosis atendidos en el Instituto Nacional de Enfermedades Neoplásicas entre 2005 y 2015. Se incluyeron 29 pacientes, 23 (79,3%) casos de listeriosis se presentaron en pacientes con neoplasia hematológica, de los cuales el 52,3% fueron leucemia linfática aguda y 39,1% linfoma no Hodgkin. Listeria monocytogenes representó el 72,4% de las especies aisladas. Veintisiete (93,1%) tuvieron criterios de sepsis y veinticuatro (82,7%) compromiso neurológico al ingreso. La presentación más común fue la bacteriemia, seguida de la meningoencefalitis (20,6%). La mortalidad global fue del 75,8%. Se concluye que la listeriosis conlleva elevada morbimortalidad en el paciente oncohematológico, por lo que debe sospecharse en el paciente admitido con sepsis y/o compromiso neurológico agudo.

ABSTRACT Listeriosis infection is a severe disease, with high morbidity and mortality in the immunocompromised patient, especially with disseminated and fatal presentations in cancer patients. A descriptive study was developed to describe the clinical and epidemiologic characteristics in oncologic patients with listeriosis in the Instituto Nacional de Enfermedades Neoplásicas between the years 2005-2015. A total of 29 patients were included; 23 (79.3%) of the listeriosis cases showed up in patients with hematological neoplasia, of which 52.1% was acute lymphatic leukemia and 39.1% non-Hodgkin's lymphoma. The 72.4% of the isolated species correspond to Listeria monocytogenes. Twenty-seven (93.1%) patients met sepsis criteria and twenty-four (82.7%) had neurologic affection. Bacteremia was the most common presentation, followed by meningoencephalitis (20.6%). Global mortality was 75.8%. In conclusion in cancer patients, listeriosis implies high morbidity and mortality. Therefore, the suspicion of this entity is mandatory in onco-hematologic patients with sepsis and acute neurologic symptoms.

Adesão, internalização e sobrevivência de Salmonella spp. e Listeria monocytogenes em mangas (Mangifera indica), variedade 'Tommy Atkins' / Adhesion, internalization and survival of Salmonella spp. and Listeria monocytogenes in mangoes (Mangifera indica), variety 'Tommy Atkins'

Surtos de salmonelose e listeriose associados ao consumo de frutas inteiras ou minimamente processadas ocorrem com frequência. O objetivo deste estudo foi investigar a capacidade de adesão e internalização de Salmonella spp. e Listeria monocytogenes em mangas (Mangifera indica) variedade Tommy Atkins, em diferentes condições de contaminação experimental e tratamento hidrotérmico, bem como avaliar a multiplicação dos patógenos internalizados na polpa das frutas durante armazenamento em refrigeração (8oC ) e temperatura ambiente (25oC). O estudo foi conduzido com as cepas S. Enteritidis ATCC 13076, S. Thyphimurium ATCC 14028, L. monocytogenes ATCC 7644 e L. monocytogenes Scott A. Inicialmente as cepas foram avaliadas segundo o índice de hidrofobicidade e capacidade de formação de biofilme em poliestireno. A adesão à superfície da manga foi avaliada por técnicas microbiológicas e também pela técnica de microscopia eletrônica de varredura. A internalização foi avaliada a partir de inoculação na cicatriz do pedúnculo (6 log UFC/mL) e após tratamento hidrotérmico e imersão em solução contaminada (6 log UFC/mL), mantidas a 8 °C e a 25 °C por 24h, 5 e 10 dias. A sobrevivência foi avaliada através da inoculação em região demarcada, em cenário de baixo (2 log UFC/mL) e alto nível de contaminação (6 log UFC/mL), a 8 °C e 25 °C, nos tempos 0, 1, 2, 3, 5 e 10 dias. A adesão foi observada nos dois patógenos, mesmo após sucessivas lavagens, com diferença significativa (p<0,05) após 1h de exposição e observou-se presença de estruturas exopolissacarídicas em diferentes tempos e condições de temperatura. A internalização ocorreu em todas as amostras avaliadas e a região do pedúnculo foi a mais afetada pela contaminação, diferindo significativamente na comparação com a região blossom end (p<0,05) a 8 °C e 25 °C. A sobrevivência foi observada nas duas temperaturas até o décimo dia. A multiplicação a 8°C foi significativamente mais baixa (p<0,05). Os resultados demonstraram que a Salmonella spp e L. monocytogenes são capazes de aderir à superfície, de internalizar e se alastrar pela polpa e ainda sobreviverem por períodos consideráveis, em 8 °C e 25 °C. Esses dados poderão auxiliar produtores e órgãos de saúde no desenvolvimento de avaliações quantitativas de risco e no estabelecimento de medidas adequadas para evitar surtos

Outbreaks of salmonellosis and listeriosis associated with the consumption of whole or minimally processed fruits occur frequently. The aim of this study was to investigate the ability of spp. and Listeria monocytogenes to adhere and internalize in mangoes (Mangifera indica) variety Tommy Atkins, under different conditions of experimental contamination and hydrothermal treatment, as well as evaluate the multiplication of the internalized pathogens in the fruit pulp during storage under refrigeration (8oC) and room temperature (25oC). The study was conducted with the strains S. Enteritidis ATCC 13076, S. Thyphimurium ATCC 14028, L. monocytogenes ATCC 7644 and L. monocytogenes Scott A. Initially the strains were evaluated according to the hydrophobicity index and capability to form biofilms on polystyrene surface. Adhesion to the mango surface was evaluated by microbiological techniques and also by scanning electron microscopy. Internalization was evaluated by inoculating the peduncle scar (6 log CFU / mL) and immersion of the fruits in contaminated solution (6 log CFU / mL) after hydrothermal treatment, during storage at 8 °C and 25 °C for 24h, 5 and 10 days. Survival was assessed by inoculation in a demarcated region, using low (2 log CFU / mL) and high level of contamination (6 log CFU / mL), and storage at 8 °C and 25 °C during 0, 1, 2, 3, 5 and 10 days. Adhesion was observed for both pathogens, even after successive washes, with a significant difference (p <0.05) after 1 h of exposure. Adhesion was mediated by exopolysaccharide structures, observed at different times and temperature conditions. Internalization occurred in all samples and the peduncle region was the most affected by the contamination, differing significantly in comparison with the blossom end region (p <0.05) at 8 °C and 25 oC. Survival was observed at both temperatures until the tenth day. The multiplication at 8 °C was significantly lower than at 25 oC (p <0.05). The results showed that Salmonella spp and L. monocytogenes were able to adhere to the surface, to internalize and spread through the pulp and still survive for considerable periods, at 8 °C and 25 °C. This data may help producers and health agencies to develop quantitative risk assessments and to establish appropriate measures to prevent outbreaks

Advances on the mechanisms regulating the formation of the biofilm of Listeria monocytogenes / 生物工程学报

Listeria monocytogenes is an important food-borne pathogen. The distribution and survival of L. monocytogenes are related to its ability to form biofilms. Biofilms are resistant to adverse environments, and bacteria separated from the biofilms may lead to persistent food contaminations. The formation, maturation and structure of biofilms depend on a variety of external and internal factors, among which a variety of regulatory mechanisms play important roles. This review summarizes the regulatory mechanisms (including intracellular, intercellular and interspecific interactions) involved in the biofilm formation of L. monocytogenes in order to control the biofilm formation in food processing environments, thus providing new intervention strategy for food safety.