RESUMEN

PURPOSE: Invasive Listeria monocytogenes infection is rare, but can lead to life-threatening complications among high-risk patients. Our aim was to assess characteristics and follow-up of adults hospitalized with invasive L. monocytogenes infection. METHODS: A retrospective observational cohort study was conducted at a national referral center between 2004 and 2019. Patients with proven invasive listeriosis, defined by the European Centre for Disease Prevention and Control criteria, were included. Data collection and follow-up were performed using the hospital electronic system, up until the last documented visit. The primary outcome was in-hospital all-cause mortality, secondary outcomes included residual neurological symptoms, brain abscess occurrence, and requirement for intensive care unit (ICU) admission. RESULTS: Altogether, 63 cases were identified (57.1% male, median age 58.8 ± 21.7 years), and 28/63 developed a complicated disease course (44.4%). At diagnosis, 38/63 (60.3%) presented with sepsis, 54/63 (85.7%) had central nervous system involvement, while 9/63 (14.3%) presented with isolated bacteremia. Frequent clinical symptoms included fever (53/63, 84.1%), altered mental state (49/63, 77.8%), with immunocompromised conditions apparent in 56/63 (88.9%). L. monocytogenes was isolated from blood (37/54, 68.5%) and cerebrospinal fluid (48/55, 87.3%), showing in vitro full susceptibility to ampicillin and meropenem (100% each), gentamicin (86.0%) and trimethoprim/sulfamethoxazole (97.7%). In-hospital all-cause mortality was 17/63 (27.0%), and ICU admission was required in 28/63 (44.4%). At discharge, residual neurological deficits (11/46, 23.9%) and brain abscess formation (6/46, 13.0%) were common. CONCLUSION: Among hospitalized adult patients with comorbidities, invasive L. monocytogenes infections are associated with high mortality and neurological complications during follow-up.

Asunto(s)

Hospitalización , Listeria monocytogenes , Listeriosis , Humanos , Masculino , Femenino , Persona de Mediana Edad , Listeriosis/mortalidad , Listeriosis/microbiología , Listeriosis/epidemiología , Listeriosis/tratamiento farmacológico , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/efectos de los fármacos , Estudios Retrospectivos , Anciano , Hungría/epidemiología , Adulto , Hospitalización/estadística & datos numéricos , Estudios de Seguimiento , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Unidades de Cuidados Intensivos/estadística & datos numéricos , Bacteriemia/microbiología , Bacteriemia/mortalidad , Bacteriemia/epidemiología , Bacteriemia/tratamiento farmacológico , Anciano de 80 o más Años , Sepsis/microbiología , Sepsis/mortalidad , Sepsis/epidemiología , Sepsis/tratamiento farmacológico , Mortalidad Hospitalaria

RESUMEN

Paracrine IL-2 signalling drives the CD8 + T cell expansion and differentiation that allow protection against viral infections, but the underlying molecular events are incompletely understood. Here we show that the transcription factor SRF, a master regulator of cytoskeletal gene expression, is required for effective IL-2 signalling during L. monocytogenes infection. Acting cell-autonomously with its actin-regulated cofactors MRTF-A and MRTF-B, SRF is dispensible for initial TCR-mediated CD8+ T cell proliferation, but is required for sustained IL-2 dependent CD8+ effector T cell expansion, and persistence of memory cells. Following TCR activation, Mrtfab-null CD8+ T cells produce IL-2 normally, but homotypic clustering is impaired both in vitro and in vivo. Expression of cytoskeletal structural and regulatory genes, most notably actins, is defective in Mrtfab-null CD8+ T cells. Activation-induced cell clustering in vitro requires F-actin assembly, and Mrtfab-null cell clusters are small, contain less F-actin, and defective in IL-2 retention. Clustering of Mrtfab-null cells can be partially restored by exogenous actin expression. IL-2 mediated CD8+ T cell proliferation during infection thus depends on the control of cytoskeletal dynamics and actin gene expression by MRTF-SRF signalling.

Asunto(s)

Linfocitos T CD8-positivos , Citoesqueleto , Interleucina-2 , Ratones Endogámicos C57BL , Factor de Respuesta Sérica , Transactivadores , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Interleucina-2/metabolismo , Interleucina-2/genética , Animales , Transactivadores/metabolismo , Transactivadores/genética , Citoesqueleto/metabolismo , Ratones , Factor de Respuesta Sérica/metabolismo , Factor de Respuesta Sérica/genética , Listeria monocytogenes/inmunología , Listeriosis/inmunología , Listeriosis/genética , Listeriosis/microbiología , Actinas/metabolismo , Regulación de la Expresión Génica , Transducción de Señal , Ratones Noqueados , Proliferación Celular , Activación de Linfocitos

RESUMEN

Listeria pathogenicity island 1 (LIPI-1) is a genetic region containing a cluster of genes essential for virulence of the bacterial pathogen Listeria monocytogenes. Main virulence factors in LIPI-1 include long 5' untranslated regions (5'UTRs), among which is Rli51, a small RNA (sRNA) in the 5'UTR of the Zn-metalloprotease-coding mpl. So far, Rli51 function and molecular mechanisms have remained obscure. Here, we show that Rli51 exhibits a dual mechanism of regulation, functioning as a cis- and as a trans-acting sRNA. Under nutrient-rich conditions, rli51-mpl transcription is prematurely terminated, releasing a short 121-nucleotide-long sRNA. Rli51 is predicted to function as a transcription attenuator that can fold into either a terminator or a thermodynamically more stable antiterminator. We show that the sRNA Rli21/RliI binds to a single-stranded RNA loop in Rli51, which is essential to mediate premature transcription termination, suggesting that sRNA binding could stabilize the terminator fold. During intracellular infection, rli51 transcription is increased, which generates a higher abundance of the short Rli51 sRNA and allows for transcriptional read-through into mpl. Comparative intracellular bacterial transcriptomics in rli51-null mutants and the wild-type reference strain EGD-e suggests that Rli51 upregulates iron-scavenging proteins and downregulates virulence factors from LIPI-1. MS2 affinity purification confirmed that Rli51 binds transcripts of the heme-binding protein Lmo2186 and Lmo0937 in vivo. These results prove that Rli51 functions as a trans-acting sRNA in intracellular bacteria. Our research shows a growth condition-dependent mechanism of regulation for Rli51, preventing unintended mpl transcription in extracellular bacteria and regulating genes important for virulence in intracellular bacteria.

Asunto(s)

Proteínas Bacterianas , Regulación Bacteriana de la Expresión Génica , Listeria monocytogenes , ARN Bacteriano , ARN Pequeño no Traducido , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/genética , Listeria monocytogenes/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , ARN Pequeño no Traducido/genética , ARN Pequeño no Traducido/metabolismo , Islas Genómicas/genética , Transcripción Genética , Regiones no Traducidas 5' , Virulencia/genética , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Humanos , Listeriosis/microbiología

RESUMEN

BACKGROUND: The foodborne bacterium Listeria monocytogenes (Lm) causes a range of diseases, from mild gastroenteritis to invasive infections that have high fatality rate in vulnerable individuals. Understanding the population genomic structure of invasive Lm is critical to informing public health interventions and infection control policies that will be most effective especially in local and regional communities. METHODS: We sequenced the whole draft genomes of 936 Lm isolates from human clinical samples obtained in a two-decade active surveillance program across 58 counties in New York State, USA. Samples came mostly from blood and cerebrospinal fluid. We characterized the phylogenetic relationships, population structure, antimicrobial resistance genes, virulence genes, and mobile genetic elements. RESULTS: The population is genetically heterogenous, consisting of lineages I-IV, 89 clonal complexes, 200 sequence types, and six known serogroups. In addition to intrinsic antimicrobial resistance genes (fosX, lin, norB, and sul), other resistance genes tetM, tetS, ermG, msrD, and mefA were sparsely distributed in the population. Within each lineage, we identified clusters of isolates with ≤ 20 single nucleotide polymorphisms in the core genome alignment. These clusters may represent isolates that share a most recent common ancestor, e.g., they are derived from the same contamination source or demonstrate evidence of transmission or outbreak. We identified 38 epidemiologically linked clusters of isolates, confirming eight previously reported disease outbreaks and the discovery of cryptic outbreaks and undetected chains of transmission, even in the rarely reported Lm lineage III (ST3171). The presence of animal-associated lineages III and IV may suggest a possible spillover of animal-restricted strains to humans. Many transmissible clones persisted over several years and traversed distant sites across the state. CONCLUSIONS: Our findings revealed the bacterial determinants of invasive listeriosis, driven mainly by the diversity of locally circulating lineages, intrinsic and mobile antimicrobial resistance and virulence genes, and persistence across geographical and temporal scales. Our findings will inform public health efforts to reduce the burden of invasive listeriosis, including the design of food safety measures, source traceback, and outbreak detection.

Asunto(s)

Listeria monocytogenes , Listeriosis , Filogenia , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/clasificación , Humanos , Listeriosis/microbiología , Listeriosis/epidemiología , Listeriosis/transmisión , Genoma Bacteriano , Polimorfismo de Nucleótido Simple , Factores de Virulencia/genética , Secuenciación Completa del Genoma , Farmacorresistencia Bacteriana/genética , Virulencia/genética

Asunto(s)

Listeriosis , Complicaciones Infecciosas del Embarazo , Humanos , Embarazo , Femenino , Complicaciones Infecciosas del Embarazo/microbiología , Complicaciones Infecciosas del Embarazo/diagnóstico , Listeriosis/diagnóstico , Antibacterianos/uso terapéutico , Adulto

RESUMEN

T cell antigen receptor (TCR) recognition followed by clonal expansion is a fundamental feature of adaptive immune responses. Here, we present a mass cytometric (CyTOF) approach to track T cell responses by combining antibodies for specific TCR Vα and Vß chains with antibodies against T cell activation and differentiation proteins in mice. This strategy identifies expansions of CD8+ and CD4+ T cells expressing specific Vß and Vα chains with varying differentiation states in response to Listeria monocytogenes, tumors and respiratory influenza infection. Expanded T cell populations expressing Vß chains could be directly linked to the recognition of specific antigens from Listeria, tumor cells or influenza. In the setting of influenza infection, we found that common therapeutic approaches of intramuscular vaccination or convalescent serum transfer altered the TCR diversity and differentiation state of responding T cells. Thus, we present a method to monitor broad changes in TCR use paired with T cell phenotyping during adaptive immune responses.

Asunto(s)

Linfocitos T CD8-positivos , Diferenciación Celular , Citometría de Flujo , Listeria monocytogenes , Listeriosis , Animales , Diferenciación Celular/inmunología , Ratones , Listeria monocytogenes/inmunología , Linfocitos T CD8-positivos/inmunología , Listeriosis/inmunología , Citometría de Flujo/métodos , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Ratones Endogámicos C57BL , Infecciones por Orthomyxoviridae/inmunología , Activación de Linfocitos/inmunología , Linfocitos T CD4-Positivos/inmunología , Inmunidad Adaptativa , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores de Antígenos de Linfocitos T/inmunología

RESUMEN

General anesthesia is thought to suppress the immune system and negatively affect postoperative infection and the long-term prognosis of cancer. However, the mechanism underlying immunosuppression induced by general anesthetics remains unclear. In this study, we focused on propofol, which is widely used for sedation under general anesthesia and intensive care and examined its effects on the T cell function and T cell-dependent immune responses. We found that propofol suppressed T cell glycolytic metabolism, differentiation into effector T cells, and cytokine production by effector T cells. CD8 T cells activated and differentiated into effector cells in the presence of propofol in vitro showed reduced antitumor activity. Furthermore, propofol treatment suppressed the increase in the number of antigen-specific CD8 T cells during Listeria infection. In contrast, the administration of propofol improved inflammatory conditions in mouse models of inflammatory diseases, such as OVA-induced allergic airway inflammation, hapten-induced contact dermatitis, and experimental allergic encephalomyelitis. These results suggest that propofol may reduce tumor and infectious immunity by suppressing the T cell function and T cell-dependent immune responses while improving the pathogenesis and prognosis of chronic inflammatory diseases by suppressing inflammation.

Asunto(s)

Linfocitos T CD8-positivos , Propofol , Propofol/farmacología , Animales , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Ratones Endogámicos C57BL , Linfocitos T/inmunología , Linfocitos T/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Inflamación/inmunología , Diferenciación Celular/efectos de los fármacos , Citocinas/metabolismo , Listeriosis/inmunología , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Femenino

RESUMEN

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.

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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.

Asunto(s)

Discitis , Listeriosis , Humanos , Listeriosis/diagnóstico , Femenino , Masculino , Discitis/microbiología , Bacteriemia/microbiología , Huésped Inmunocomprometido , Listeria monocytogenes/aislamiento & purificación , Anciano , Persona de Mediana Edad

RESUMEN

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.

Asunto(s)

Antibacterianos , Absceso Encefálico , Listeria monocytogenes , Listeriosis , Infecciones Estreptocócicas , Humanos , Masculino , Absceso Encefálico/microbiología , Absceso Encefálico/tratamiento farmacológico , Listeria monocytogenes/aislamiento & purificación , Adulto , Antibacterianos/uso terapéutico , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/diagnóstico , Listeriosis/tratamiento farmacológico , Listeriosis/diagnóstico , Listeriosis/microbiología , Imagen por Resonancia Magnética , Ampicilina/uso terapéutico , Inmunocompetencia , Amoxicilina/uso terapéutico , Amoxicilina/administración & dosificación

RESUMEN

The tight and coordinated regulation of virulence gene expression is crucial to ensure the survival and persistence of bacterial pathogens in different contexts within their hosts. Considering this, bacteria do not express virulence factors homogenously in time and space, either due to their associated fitness cost or to their detrimental effect at specific infection stages. To efficiently infect and persist into their hosts, bacteria have thus to monitor environmental cues or chemical cell-to-cell signaling mechanisms that allow their transition from the external environment to the host, and therefore adjust gene expression levels, intrinsic biological activities, and appropriate behaviors. Listeria monocytogenes (Lm), a major Gram-positive facultative intracellular pathogen, stands out for its adaptability and capacity to thrive in a wide range of environments. Because of that, Lm presents itself as a significant concern in food safety and public health, that can lead to potentially life-threatening infections in humans. A deeper understanding of the intricate bacterial virulence mechanisms and the signals that control them provide valuable insights into the dynamic interplay between Lm and the host. Therefore, this review addresses the role of some crucial signals behind Lm pathogenic virulence mechanisms and explores how the ability to assimilate and interpret these signals is fundamental for pathogenesis, identifying potential targets for innovative antimicrobial strategies.

Asunto(s)

Regulación Bacteriana de la Expresión Génica , Listeria monocytogenes , Listeriosis , Factores de Virulencia , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/genética , Listeria monocytogenes/metabolismo , Listeria monocytogenes/fisiología , Humanos , Virulencia , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Listeriosis/microbiología , Animales , Transducción de Señal , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Interacciones Huésped-Patógeno

RESUMEN

Sepsis is a complex condition of inflammatory and immune dysregulation, triggered by severe infection. In survivors, chronic inflammation and immune dysregulation linger, facilitating the emergence of infections. CD8 dysfunction contributes to immunosuppression in sepsis survivors. We devised an animal model that enabled us to identify and analyze CD8-intrinsic defects induced by sepsis. We adoptively transferred CD45.1 CD8 OT-I T cells into CD45.2 congenic mice and subjected them to cecal ligature and puncture, to induce abdominal sepsis. One month later, we isolated the transferred CD8 cells. Surface marker expression confirmed they had not been activated through the TCR. CD8 OT-I T cells isolated from septic (or sham-operated) mice were transferred to second recipients, which were challenged with OVA-expressing Listeria monocytogenes. We compared effector capacities between OT-I cells exposed to sepsis and control cells. Naive mice that received OT-I cells exposed to sepsis had higher bacterial burden and a shorter survival when challenged with OVA-expressing L. monocytogenes. OT-I cells isolated from septic mice produced less IFN-γ but had conserved activation, expansion potential, and cytotoxic function. We observed lower transcript levels of IFN-γ and of the long noncoding RNA Ifng-as1, a local regulator of the epigenetic landscape, in cells exposed to sepsis. Accordingly, local abundance of a histone modification characteristic of active promoter regions was reduced in sepsis-exposed CD8 T cells. Our results identify a mechanism through which inflammation in the context of sepsis affects CD8 T cell function intrinsically.

Asunto(s)

Linfocitos T CD8-positivos , Cromatina , Interferón gamma , Listeria monocytogenes , Sepsis , Animales , Sepsis/inmunología , Linfocitos T CD8-positivos/inmunología , Ratones , Interferón gamma/inmunología , Cromatina/inmunología , Cromatina/metabolismo , Listeria monocytogenes/inmunología , Ratones Endogámicos C57BL , Traslado Adoptivo , Modelos Animales de Enfermedad , Listeriosis/inmunología , Activación de Linfocitos/inmunología

RESUMEN

An important property of the host innate immune response during microbial infection is its ability to control the expression of antimicrobial effector proteins, but how this occurs post-transcriptionally is not well defined. Here, we describe a critical antibacterial role for the classic antiviral gene 2'-5'-oligoadenylate synthetase 1 (OAS1). Human OAS1 and its mouse ortholog, Oas1b, are induced by interferon-γ and protect against cytosolic bacterial pathogens such as Francisella novicida and Listeria monocytogenes in vitro and in vivo. Proteomic and transcriptomic analysis showed reduced IRF1 protein expression in OAS1-deficient cells. Mechanistically, OAS1 binds and localizes IRF1 mRNA to the rough endoplasmic reticulum (ER)-Golgi endomembranes, licensing effective translation of IRF1 mRNA without affecting its transcription or decay. OAS1-dependent translation of IRF1 leads to the enhanced expression of antibacterial effectors, such as GBPs, which restrict intracellular bacteria. These findings uncover a noncanonical function of OAS1 in antibacterial innate immunity.

Asunto(s)

2',5'-Oligoadenilato Sintetasa , Inmunidad Innata , Factor 1 Regulador del Interferón , 2',5'-Oligoadenilato Sintetasa/metabolismo , 2',5'-Oligoadenilato Sintetasa/genética , Factor 1 Regulador del Interferón/metabolismo , Factor 1 Regulador del Interferón/genética , Animales , Humanos , Ratones , Biosíntesis de Proteínas/inmunología , Listeria monocytogenes/inmunología , Ratones Noqueados , Ratones Endogámicos C57BL , Listeriosis/inmunología , Interferón gamma/metabolismo , Interferón gamma/inmunología

RESUMEN

Innate immune pattern recognition receptors, such as the Toll-like receptors (TLRs), are key mediators of the immune response to infection and central to our understanding of health and disease1. After microbial detection, these receptors activate inflammatory signal transduction pathways that involve IκB kinases, mitogen-activated protein kinases, ubiquitin ligases and other adaptor proteins. The mechanisms that connect the proteins in the TLR pathways are poorly defined. To delineate TLR pathway activities, we engineered macrophages to enable microscopy and proteomic analysis of the endogenous myddosome constituent MyD88. We found that myddosomes form transient contacts with activated TLRs and that TLR-free myddosomes are dynamic in size, number and composition over the course of 24 h. Analysis using super-resolution microscopy revealed that, within most myddosomes, MyD88 forms barrel-like structures that function as scaffolds for effector protein recruitment. Proteomic analysis demonstrated that myddosomes contain proteins that act at all stages and regulate all effector responses of the TLR pathways, and genetic analysis defined the epistatic relationship between these effector modules. Myddosome assembly was evident in cells infected with Listeria monocytogenes, but these bacteria evaded myddosome assembly and TLR signalling during cell-to-cell spread. On the basis of these findings, we propose that the entire TLR signalling pathway is executed from within the myddosome.

Asunto(s)

Macrófagos , Transducción de Señal , Receptores Toll-Like , Animales , Humanos , Ratones , Listeria monocytogenes/inmunología , Listeriosis/inmunología , Listeriosis/microbiología , Listeriosis/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Macrófagos/microbiología , Factor 88 de Diferenciación Mieloide/metabolismo , Proteómica , Receptores Toll-Like/metabolismo , Microscopía , Inmunidad Innata

RESUMEN

Dissemination of food-borne L. monocytogenes in the host relies on internalin-mediated invasion, but the underlying invasion strategies remain elusive. Here we use live-cell microscopy to follow single cell interactions between individual human cells and L. monocytogenes and elucidate mechanisms associated with internalin B (InlB)-mediated invasion. We demonstrate that whilst a replicative invasion of nonphagocytic cells is a rare event even at high multiplicities of invasion, L. monocytogenes overcomes this by utilising a strategy relaying on PrfA-mediated ActA-based aggregation. We show that L. monocytogenes forms aggregates in extracellular host cell environment, which promote approximately 5-fold more host cell adhesions than the non-aggregating actA-ΔC mutant (which lacks the C-terminus coding region), with the adhering bacteria inducing 3-fold more intracellular invasions. Aggregation is associated with robust MET tyrosine kinase receptor clustering in the host cells, a hallmark of InlB-mediated invasion, something not observed with the actA-ΔC mutant. Finally, we show via RNA-seq analyses that aggregation involves a global adaptive response to host cell environment (including iron depletion), resulting in metabolic changes in L. monocytogenes and upregulation of the PrfA virulence regulon. Overall, our analyses provide new mechanistic insights into internalin-mediated host-pathogen interactions of L. monocytogenes.

Asunto(s)

Adhesión Bacteriana , Proteínas Bacterianas , Listeria monocytogenes , Listeria monocytogenes/genética , Listeria monocytogenes/patogenicidad , Listeria monocytogenes/fisiología , Listeria monocytogenes/metabolismo , Humanos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Interacciones Huésped-Patógeno , Listeriosis/microbiología , Factores de Terminación de Péptidos/metabolismo , Factores de Terminación de Péptidos/genética , Regulación Bacteriana de la Expresión Génica , Virulencia/genética , Factores de Virulencia/genética , Factores de Virulencia/metabolismo

RESUMEN

PURPOSE: Listeria monocytogenes causes severe bacterial infections with the highest mortality rate among foodborne pathogens in Europe. Combination treatment with ampicillin and gentamicin is recommended for invasive manifestations. However, evidence to support this treatment approach remains limited due to a lack of randomised controlled trials. To explore this critical issue further, we conducted this retrospective, single-center study. METHODS: We identified all patients hospitalized with invasive listeriosis at the University Medical Center Hamburg-Eppendorf between 2009 and 2020 and analyzed the effect of gentamicin combination treatment versus monotherapy on 90-day mortality. RESULTS: In total, 36 patients with invasive listeriosis were included, of which 21 patients received gentamicin combination treatment and 15 received monotherapy. The mean age-adjusted Charlson Comorbidity Index (aaCCI) value was lower in the gentamicin combination treatment group (5.4 vs. 7.4). Neurolisteriosis was more common in the gentamicin group (81% vs. 20%). The 90-day mortality was with significantly lower in the gentamicin combination treatment group (10%) compared to the monotherapy group (60%). Multivariable cox regression analysis, adjusted for a propensity score computed based on neurolisteriosis, aaCCI and sex, revealed a significantly reduced hazard ratio of 0.07 (95% CI: 0.01-0.53, p = 0.01) for 90-day mortality for the gentamicin combination treatment. CONCLUSION: This retrospective study highlights the benefit of gentamicin combination treatment in reducing the 90-day mortality rate among patients with invasive listeriosis. The high prevalence of monotherapy in this study cohort raises concerns about the adequacy of antibiotic therapy in clinical practice.

Asunto(s)

Antibacterianos , Quimioterapia Combinada , Gentamicinas , Listeriosis , Humanos , Gentamicinas/uso terapéutico , Estudios Retrospectivos , Masculino , Femenino , Anciano , Antibacterianos/uso terapéutico , Listeriosis/tratamiento farmacológico , Listeriosis/mortalidad , Persona de Mediana Edad , Anciano de 80 o más Años , Listeria monocytogenes/efectos de los fármacos

RESUMEN

BACKGROUND: Listeriosis is a global health threat to both animals and humans, especially in developing countries. This study was designed to isolate Listeria monocytogenes from faeces; environmental samples; and cow, sheep and goat milk, as well as human stool, to study its molecular characteristics and antibiotic sensitivity in the New Valley and Beheira Governorates, Egypt. The isolation and identification of L. monocytogenes were carried out using traditional culture and biochemical methods, followed by antibiography, genus confirmation of some isolates and detection and sequencing of InlB genes via PCR. RESULTS: Out of 2097 examined samples, the prevalence of L. monocytogenes was 13.4% in animals; the prevalence was 9.2%, 2.4%, 25.4%, 4%, 42.4%, and 6.4% in cattle faeces, cattle milk, sheep faeces, sheep milk, goat faeces, and goat milk, respectively. However, the prevalence of L. monocytogenes was 8.3% in human samples. Both animal and human isolates showed 100% resistance to trimethoprim-sulfamethoxazole, and the isolates showed the highest sensitivity to flumequine (100%), amikacin (99.2%), gentamicin (97.6%), and levofloxacin (94.6%). Multidrug resistance (MDR) was detected in 86.9% of the tested isolates. The 16 S rRNA and inlB genes were detected in 100% of the randomly selected L. monocytogenes isolates. Phylogenetic analysis of three isolates based on the inlB gene showed 100% identity between faecal, milk and human stool isolates. CONCLUSIONS: Faeces and milk are major sources of listeriosis, and the high degree of genetic similarity between animal and human isolates suggests the possibility of zoonotic circulation. The high prevalence of MDR L. monocytogenes in both animal and human samples could negatively impact the success of prevention and treatments for animal and human diseases, thereby imposing serious risks to public health.

Asunto(s)

Antibacterianos , Heces , Cabras , Listeria monocytogenes , Listeriosis , Leche , Animales , Egipto/epidemiología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Humanos , Prevalencia , Ovinos , Antibacterianos/farmacología , Bovinos , Heces/microbiología , Listeriosis/veterinaria , Listeriosis/epidemiología , Listeriosis/microbiología , Leche/microbiología , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana/genética

RESUMEN

Listeria monocytogenes in beef receives less attention compared to other pathogens such as Salmonella and Escherichia coli. To address this gap, we conducted a literature review focusing on the presence of L. monocytogenes in beef. This review encompasses the pathogenic mechanisms, routes of contamination, prevalence rates, and the laws and regulations employed in various countries. Our findings reveal a prevalence of L. monocytogenes in beef and beef products ranging from 2.5% to 59.4%. Notably, serotype 4b was most frequently isolated in cases of beef contamination during food processing, with the skinning and evisceration stages identified as critical points of contamination.

Asunto(s)

Listeria monocytogenes , Carne Roja , Listeria monocytogenes/aislamiento & purificación , Listeria monocytogenes/genética , Carne Roja/microbiología , Animales , Bovinos , Microbiología de Alimentos , Humanos , Contaminación de Alimentos/análisis , Prevalencia , Listeriosis/microbiología , Listeriosis/epidemiología , Manipulación de Alimentos , Serogrupo

RESUMEN

Listeria monocytogenes is a Gram-positive facultative anaerobic bacterium that is ubiquitous in the environment and can cause severe infections in immunocompromised individuals, pregnant women, and newborns. Listeriosis can manifest as meningitis, encephalitis, or sepsis, and its diagnosis requires a high index of suspicion. The case is reported of a rare presentation of rhombencephalitis by listeriosis in a 61-year-old male who initially suffered from subacute gastric disturbances and fever. Neurological consultation showed abnormal functions of cranial nerves and meningeal signs were observed. MRI revealed a poorly demarcated focus of approximately 45 × 16 × 15mm, indicating possible inflammatory processes, necessitating a lumbar puncture. Assessment of the CSF indicated infection with the bacterium- Listeria Monocytogenes, with the final diagnosis of Listeriosis encephalitis. Despite antibiotic therapy of Ceftazidine and Ampicillin, the patient's condition deteriorated, followed by death.

Asunto(s)

Encefalitis , Listeria monocytogenes , Listeriosis , Humanos , Masculino , Listeriosis/diagnóstico , Listeriosis/tratamiento farmacológico , Listeriosis/microbiología , Persona de Mediana Edad , Resultado Fatal , Listeria monocytogenes/aislamiento & purificación , Encefalitis/microbiología , Encefalitis/tratamiento farmacológico , Encefalitis/diagnóstico , Antibacterianos/uso terapéutico , Antibacterianos/administración & dosificación , Rombencéfalo/microbiología

RESUMEN

Bacteriocins have the potential to effectively improve food-borne infections or gastrointestinal diseases and hold promise as viable alternatives to antibiotics. This study aimed to explore the antibacterial activity of three bacteriocins (nisin, enterocin Gr17, and plantaricin RX-8) and their ability to attenuate intestinal barrier dysfunction and inflammatory responses induced by Listeria monocytogenes, respectively. Bacteriocins have shown excellent antibacterial activity against L. monocytogenes without causing any cytotoxicity. Bacteriocins inhibited the adhesion and invasion of L. monocytogenes on Caco-2 cells, lactate dehydrogenase (LDH), trans-epithelial electrical resistance (TEER), and cell migration showed that bacteriocin improved the permeability of Caco-2 cells. These results were attributed to the promotion of tight junction proteins (TJP) assembly, specifically zonula occludens-1 (ZO-1), occludin, and claudin-1. Furthermore, bacteriocins could alleviate inflammation by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways and reducing the secretion of interleukin-6 (IL-6), interleukin-1 ß (IL-1ß) and tumor necrosis factor α (TNF-α). Among three bacteriocins, plantaricin RX-8 showed the best antibacterial activity against L. monocytogenes and the most pronounced protective effect on the intestinal barrier due to its unique structure. Based on our findings, we hypothesized that bacteriocins may inhibit the adhesion and invasion of L. monocytogenes by competing adhesion sites. Moreover, they may further enhance intestinal barrier function by inhibiting the expression of L. monocytogenes virulence factors, increasing the expression of TJP and decreasing the secretion of inflammatory factors. Therefore, bacteriocins will hopefully be an effective alternative to antibiotics, and this study provides valuable insights into food safety concerns. KEY POINTS: • Bacteriocins show excellent antibacterial activity against L. monocytogenes • Bacteriocins improve intestinal barrier damage and inflammatory response • Plantaricin RX-8 has the best protective effect on Caco-2 cells damage.

Asunto(s)

Antibacterianos , Bacteriocinas , Listeria monocytogenes , Listeria monocytogenes/efectos de los fármacos , Bacteriocinas/farmacología , Humanos , Células CACO-2 , Antibacterianos/farmacología , Inflamación , FN-kappa B/metabolismo , Adhesión Bacteriana/efectos de los fármacos , Proteínas de Uniones Estrechas/metabolismo , Citocinas/metabolismo , Listeriosis/microbiología , Listeriosis/tratamiento farmacológico , Movimiento Celular/efectos de los fármacos

RESUMEN

Listeria monocytogenes (Lm) is a highly pathogenic bacterium that can cause listeriosis, a relatively rare food-borne infectious disease that affects farm, domestic, wild animals and humans as well. The infected livestock is the frequent sources of Lm. Vaccination is one of the methods of controlling listeriosis in target farm animals to prevent Lm-associated food contamination. Here we report the complete sequence of the Lm strain AUF attenuated from a fully-virulent Lm strain by ultraviolet irradiation, successfully used since the 1960s as a live whole-cell veterinary vaccine. The de novo assembled genome consists of a circular chromosome of 2,942,932 bp length, including more than 2,800 CDSs, 17 pseudogenes, 5 antibiotic resistance genes, and 56/92 virulence genes. Two wild Lm strains, the EGD and the 10403S that is also used in cancer Immunotherapy, were the closest homologs for the Lm strain AUF. Although all three strains belonged to different sequence types (ST), namely ST12, ST85, and ST1538, they were placed in the same genetic lineage II, CC7.

Asunto(s)

Genoma Bacteriano , Listeria monocytogenes , Listeriosis , Animales , Vacunas Bacterianas/inmunología , Listeria monocytogenes/genética , Listeriosis/veterinaria , Vacunas Atenuadas