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1.
Cell Host Microbe ; 26(5): 691-701.e5, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31726031

RESUMO

Understanding the role of the microbiota components in either preventing or favoring enteric infections is critical. Here, we report the discovery of a Listeria bacteriocin, Lmo2776, which limits Listeria intestinal colonization. Oral infection of conventional mice with a Δlmo2776 mutant leads to a thinner intestinal mucus layer and higher Listeria loads both in the intestinal content and deeper tissues compared to WT Listeria. This latter difference is microbiota dependent, as it is not observed in germ-free mice. Strikingly, it is phenocopied by pre-colonization of germ-free mice before Listeria infection with Prevotella copri, an abundant gut-commensal bacteria, but not with the other commensals tested. We further show that Lmo2776 targets P. copri and reduces its abundance. Together, these data unveil a role for P.copri in exacerbating intestinal infection, highlighting that pathogens such as Listeria may selectively deplete microbiota bacterial species to avoid excessive inflammation.

3.
PLoS Pathog ; 15(10): e1008032, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31589660

RESUMO

The intracellular pathogen Listeria monocytogenes is distinguished by its ability to invade and replicate within mammalian cells. Remarkably, of the 15 serovars within the genus, strains belonging to serovar 4b cause the majority of listeriosis clinical cases and outbreaks. The Listeria O-antigens are defined by subtle structural differences amongst the peptidoglycan-associated wall-teichoic acids (WTAs), and their specific glycosylation patterns. Here, we outline the genetic determinants required for WTA decoration in serovar 4b L. monocytogenes, and demonstrate the exact nature of the 4b-specific antigen. We show that challenge by bacteriophages selects for surviving clones that feature mutations in genes involved in teichoic acid glycosylation, leading to a loss of galactose from both wall teichoic acid and lipoteichoic acid molecules, and a switch from serovar 4b to 4d. Surprisingly, loss of this galactose decoration not only prevents phage adsorption, but leads to a complete loss of surface-associated Internalin B (InlB),the inability to form actin tails, and a virulence attenuation in vivo. We show that InlB specifically recognizes and attaches to galactosylated teichoic acid polymers, and is secreted upon loss of this modification, leading to a drastically reduced cellular invasiveness. Consequently, these phage-insensitive bacteria are unable to interact with cMet and gC1q-R host cell receptors, which normally trigger cellular uptake upon interaction with InlB. Collectively, we provide detailed mechanistic insight into the dual role of a surface antigen crucial for both phage adsorption and cellular invasiveness, demonstrating a trade-off between phage resistance and virulence in this opportunistic pathogen.

4.
Nature ; 574(7777): 259-263, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31554973

RESUMO

Chikungunya virus (CHIKV) is a re-emerging alphavirus that is transmitted to humans by mosquito bites and causes musculoskeletal and joint pain1,2. Despite intensive investigations, the human cellular factors that are critical for CHIKV infection remain unknown, hampering the understanding of viral pathogenesis and the development of anti-CHIKV therapies. Here we identified the four-and-a-half LIM domain protein 1 (FHL1)3 as a host factor that is required for CHIKV permissiveness and pathogenesis in humans and mice. Ablation of FHL1 expression results in the inhibition of infection by several CHIKV strains and o'nyong-nyong virus, but not by other alphaviruses and flaviviruses. Conversely, expression of FHL1 promotes CHIKV infection in cells that do not normally express it. FHL1 interacts directly with the hypervariable domain of the nsP3 protein of CHIKV and is essential for the replication of viral RNA. FHL1 is highly expressed in CHIKV-target cells and is particularly abundant in muscles3,4. Dermal fibroblasts and muscle cells derived from patients with Emery-Dreifuss muscular dystrophy that lack functional FHL15 are resistant to CHIKV infection. Furthermore,  CHIKV infection  is undetectable in Fhl1-knockout mice. Overall, this study shows that FHL1 is a key factor expressed by the host that enables CHIKV infection and identifies the interaction between nsP3 and FHL1 as a promising target for the development of anti-CHIKV therapies.

5.
J Infect ; 79(4): 322-331, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31376457

RESUMO

BACKGROUND: Listeria monocytogenes-associated endovascular infections are not well characterized. METHODS: Retrospective study of 71 culture-proven cases reported to the French National Reference Center for Listeria from 1993 to 2018. RESULTS: Seventy-one cases were identified: 42 with vascular aneurysms/prosthetic infections, 27 with endocarditis, 2 with both. Fifty-eight were men (82%); median age was 75 years [46-92]; 93% reported co-morbidities (66/71), including 50% with immunosuppressive conditions. Vascular infections consisted of infected aneurysms (68%) or prosthetic graft infections (32%); vascular rupture was reported in 25/42 (60%). Tissue samples grew L. monocytogenes in 98% (43/44) and blood cultures in 64% (27/42). Endocarditis cases involved prosthetic or native valves or intracardiac devices in respectively 62% (18/29), 28% (8/29) and 10% (3/29). Infected valves were aortic (62%, 16/26), mitral (31%, 8/26) or both (8%, 2/26); 38% patients required surgery; 45% displayed heart failure; 17% had concomitant neurolisteriosis. In-hospital mortality in vascular infections was 12% (5/42) and 41% (12/29) for Lm-associated endocarditis. CONCLUSIONS: Endovascular listeriosis is a rare but severe infection. It manifests as vascular infections and endocarditis, mostly in older patients with vascular or cardiac valve prosthetic devices and co-morbidities. Mortality in Lm-associated endocarditis is twice higher than with other pathogens, requiring prompt recognition and treatment.

7.
Science ; 365(6449): 176-180, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31296770

RESUMO

Elevated levels of type I interferon (IFN) during pregnancy are associated with intrauterine growth retardation, preterm birth, and fetal demise through mechanisms that are not well understood. A critical step of placental development is the fusion of trophoblast cells into a multinucleated syncytiotrophoblast (ST) layer. Fusion is mediated by syncytins, proteins deriving from ancestral endogenous retroviral envelopes. Using cultures of human trophoblasts or mouse cells, we show that IFN-induced transmembrane proteins (IFITMs), a family of restriction factors blocking the entry step of many viruses, impair ST formation and inhibit syncytin-mediated fusion. Moreover, the IFN inducer polyinosinic:polycytidylic acid promotes fetal resorption and placental abnormalities in wild-type but not in Ifitm-deleted mice. Thus, excessive levels of IFITMs may mediate the pregnancy complications observed during congenital infections and other IFN-induced pathologies.

8.
Nat Commun ; 10(1): 2488, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171794

RESUMO

Listeria monocytogenes (Lm) is a major human and animal foodborne pathogen. Here we show that hypervirulent Lm clones, particularly CC1, are strongly associated with dairy products, whereas hypovirulent clones, CC9 and CC121, are associated with meat products. Clone adaptation to distinct ecological niches and/or different food products contamination routes may account for this uneven distribution. Indeed, hypervirulent clones colonize better the intestinal lumen and invade more intestinal tissues than hypovirulent ones, reflecting their adaption to host environment. Conversely, hypovirulent clones are adapted to food processing environments, with a higher prevalence of stress resistance and benzalkonium chloride tolerance genes and a higher survival and biofilm formation capacity in presence of sub-lethal benzalkonium chloride concentrations. Lm virulence heterogeneity therefore reflects the diversity of the ecological niches in which it evolves. These results also have important public health implications and may help in reducing food contamination and improving food consumption recommendations to at-risk populations.


Assuntos
Laticínios/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Intestinos/microbiologia , Listeria monocytogenes/patogenicidade , Produtos da Carne/microbiologia , Virulência , Adaptação Fisiológica , Animais , Anti-Infecciosos Locais , Compostos de Benzalcônio , Biofilmes , Células Clonais , Farmacorresistência Bacteriana/genética , Ecossistema , Contaminação de Alimentos , Manipulação de Alimentos , Humanos , Listeria monocytogenes/genética
9.
Environ Microbiol ; 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31251828

RESUMO

Advances in whole-genome sequencing (WGS) technologies have documented genetic diversity and epidemiology of the major foodborne pathogen Listeria monocytogenes (Lm) in Europe and North America, but data concerning South America are scarce. Here, we examined the population structure and genetic diversity of this major foodborne pathogen collected in Brazil. Based on core genome multilocus sequence typing (cgMLST), isolates from lineages I (n = 22; 63%) and II (n = 13; 37%) were distributed into 10 different sublineages (SLs) and represented 31 new cgMLST types (CTs). The most prevalent SLs were SL9 (n = 9; 26%), SL3 (n = 6; 17%) and SL2 and SL218 (n = 5; 14%). Isolates belonging to CTs L2-SL9-ST9-CT4420 and L1-SL315-ST520-CT4429 were collected 3 and 9 years apart, respectively, revealing long-term persistence of Lm in Brazil. Genetic elements associated with stress survival were present in 60% of isolates (57% SSI-1 and 3% SSI-2). Pathogenic islands were present in 100% (LIPI-1), 43% (LIPI-3) and 6% (LIPI-4) of the isolates. Mutations leading to premature stop codons were detected in the prfA and inlA virulence genes. This study is an important contribution to understanding the genomic diversity and epidemiology of Lm in South America. In addition, the results highlight the importance of using WGS to reveal Lm long-term persistence.

10.
Microb Genom ; 5(2)2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30775964

RESUMO

We present the LiSEQ (Listeria SEQuencing) project, funded by the European Food Safety Agency (EFSA) to compare Listeria monocytogenes isolates collected in the European Union from ready-to-eat foods, compartments along the food chain (e.g. food-producing animals, food-processing environments) and humans. In this article, we report the molecular characterization of a selection of this data set employing whole-genome sequencing analysis. We present an overview of the strain diversity observed in different sampled sources, and characterize the isolates based on their virulence and resistance profile. We integrate into our analysis the global L. monocytogenes genome collection described by Moura and colleagues in 2016 to assess the representativeness of the LiSEQ collection in the context of known L. monocytogenes strain diversity.


Assuntos
Laticínios/microbiologia , Produtos Pesqueiros/microbiologia , Listeria monocytogenes/classificação , Listeriose/microbiologia , Produtos da Carne/microbiologia , Animais , Estudos Transversais , Farmacorresistência Bacteriana/genética , Europa (Continente) , Manipulação de Alimentos , Microbiologia de Alimentos , Variação Genética , Humanos , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Virulência/genética , Sequenciamento Completo do Genoma
11.
Infect Immun ; 87(4)2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30670551

RESUMO

Listeria innocua is considered a nonpathogenic Listeria species. Natural atypical hemolytic L. innocua isolates have been reported but have not been characterized in detail. Here, we report the genomic and functional characterization of representative isolates from the two known natural hemolytic L. innocua clades. Whole-genome sequencing confirmed the presence of Listeria pathogenicity islands (LIPI) characteristic of Listeria monocytogenes species. Functional assays showed that LIPI-1 and inlA genes are transcribed, and the corresponding gene products are expressed and functional. Using in vitro and in vivo assays, we show that atypical hemolytic L. innocua is virulent, can actively cross the intestinal epithelium, and spreads systemically to the liver and spleen, albeit to a lesser degree than the reference L. monocytogenes EGDe strain. Although human exposure to hemolytic L. innocua is likely rare, these findings are important for food safety and public health. The presence of virulence traits in some L. innocua clades supports the existence of a common virulent ancestor of L. monocytogenes and L. innocua.


Assuntos
Doenças das Aves/microbiologia , Listeria monocytogenes/patogenicidade , Listeria/isolamento & purificação , Listeria/patogenicidade , Listeriose/microbiologia , Listeriose/veterinária , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Patos , Fezes/microbiologia , Galliformes , Genoma Bacteriano , Ilhas Genômicas , Humanos , Listeria/classificação , Listeria/genética , Listeria monocytogenes/classificação , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Filogenia , Sorotipagem , Virulência , Sequenciamento Completo do Genoma
12.
J Clin Immunol ; 39(1): 55-64, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30552536

RESUMO

PURPOSE: Progressive multifocal leukoencephalopathy (PML) is a rare but severe demyelinating disease caused by the polyomavirus JC (JCV) in immunocompromised patients. We report a series of patients with primary immune deficiencies (PIDs) who developed PML. METHODS: Retrospective observational study including PID patients with PML. Clinical, immunological, imaging features, and outcome are provided for each patient. RESULTS: Eleven unrelated patients with PIDs developed PML. PIDs were characterized by a wide range of syndromic or genetically defined defects, mostly with combined B and T cell impairment. Genetic diagnosis was made in 7 patients. Before the development of PML, 10 patients had recurrent infections, 7 had autoimmune and/or inflammatory manifestations, and 3 had a history of malignancies. Immunologic investigations showed CD4+ lymphopenia (median 265, range 50-344) in all cases. Six patients received immunosuppressive therapy in the year before PML onset, including prolonged steroid therapy in 3 cases, rituximab in 5 cases, anti-TNF-α therapy, and azathioprine in 1 case each. Despite various treatments, all but 1 patient died after a median of 8 months following PML diagnosis. CONCLUSION: PML is a rare but fatal complication of PIDs. Many cases are secondary to immunosuppressive therapy warranting careful evaluation before initiation subsequent immunosuppression during PIDs.


Assuntos
Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/imunologia , Leucoencefalopatia Multifocal Progressiva/etiologia , Leucoencefalopatia Multifocal Progressiva/imunologia , Adolescente , Adulto , Azatioprina/uso terapêutico , Linfócitos B/imunologia , Feminino , Humanos , Imunoterapia/métodos , Vírus JC/imunologia , Leucoencefalopatia Multifocal Progressiva/terapia , Linfopenia/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Rituximab/uso terapêutico , Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/imunologia , Adulto Jovem
13.
Artigo em Inglês | MEDLINE | ID: mdl-30457511

RESUMO

During a screening of Listeria species in food samples in Thailand, a Listeria-like bacterium was recovered from fried chicken and could not be assigned to any known species. Phylogenetic analysis based on the 16S rRNA gene and on 243 Listeria core genes placed the novel taxon within the Listeria aquatica, Listeria floridensis, Listeria fleishmannii and Listeria costaricensis clade (Listeria sensu lato), with highest similarity to L. floridensis (98.9 %) and L. costaricensis (98.8 %). Whole-genome sequence analyses based on the average nucleotide blast identity (ANI<86 %), the pairwise amino acid identity (AAI>64 %) and on the percentage of conserved proteins (POCP>77 %) with currently known Listeria species confirmed that the strain constituted a new taxon within the genus Listeria. At the phenotypical level, it differs from other Listeria species by the production of acid from d-tagatose and inositol. The name Listeria thailandensis sp. nov. is proposed for the novel species, and is represented by the type strain CLIP 2015/00305T (=CIP 111635T=DSM 107638T).

14.
Emerg Infect Dis ; 24(12): 2382-2386, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30457541

RESUMO

We report a disseminated infection caused by Spiroplasma apis, a honeybee pathogen, in a patient in France who had X-linked agammaglobulinemia. Identification was challenging because initial bacterial cultures and direct examination by Gram staining were negative. Unexplained sepsis in patients with agammaglobulinemia warrants specific investigation to identify fastidious bacteria such as Spiroplasma spp.

15.
J Exp Med ; 215(11): 2936-2954, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-30355616

RESUMO

The foodborne pathogen Listeria monocytogenes (Lm) crosses the intestinal villus epithelium via goblet cells (GCs) upon the interaction of Lm surface protein InlA with its receptor E-cadherin. Here, we show that Lm infection accelerates intestinal villus epithelium renewal while decreasing the number of GCs expressing luminally accessible E-cadherin, thereby locking Lm portal of entry. This novel innate immune response to an enteropathogen is triggered by the infection of Peyer's patch CX3CR1+ cells and the ensuing production of IL-23. It requires STAT3 phosphorylation in epithelial cells in response to IL-22 and IL-11 expressed by lamina propria gp38+ stromal cells. Lm-induced IFN-γ signaling and STAT1 phosphorylation in epithelial cells is also critical for Lm-associated intestinal epithelium response. GC depletion also leads to a decrease in colon mucus barrier thickness, thereby increasing host susceptibility to colitis. This study unveils a novel innate immune response to an enteropathogen, which implicates gp38+ stromal cells and locks intestinal villus invasion, but favors colitis.

16.
PLoS Genet ; 14(10): e1007727, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30321174

RESUMO

[This corrects the article DOI: 10.1371/journal.pgen.1007525.].

17.
PLoS Genet ; 14(9): e1007525, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30180166

RESUMO

Elucidating the relationships between antimicrobial resistance and virulence is key to understanding the evolution and population dynamics of resistant pathogens. Here, we show that the susceptibility of the gram-positive bacterium Listeria monocytogenes to the antibiotic fosfomycin is a complex trait involving interactions between resistance and virulence genes and the environment. We found that a FosX enzyme encoded in the listerial core genome confers intrinsic fosfomycin resistance to both pathogenic and non-pathogenic Listeria spp. However, in the genomic context of the pathogenic L. monocytogenes, FosX-mediated resistance is epistatically suppressed by two members of the PrfA virulence regulon, hpt and prfA, which upon activation by host signals induce increased fosfomycin influx into the bacterial cell. Consequently, in infection conditions, most L. monocytogenes isolates become susceptible to fosfomycin despite possessing a gene that confers high-level resistance to the drug. Our study establishes the molecular basis of an epistatic interaction between virulence and resistance genes controlling bacterial susceptibility to an antibiotic. The reported findings provide the rationale for the introduction of fosfomycin in the treatment of Listeria infections even though these bacteria are intrinsically resistant to the antibiotic in vitro.

18.
Nat Microbiol ; 3(9): 966-968, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30143802
19.
J Clin Invest ; 128(10): 4697-4710, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30063220

RESUMO

Zika virus (ZIKV) is a teratogenic mosquito-borne flavivirus that can be sexually transmitted from man to woman. The finding of high viral loads and prolonged viral shedding in semen suggests that ZIKV replicates within the human male genital tract, but its target organs are unknown. Using ex vivo infection of organotypic cultures, we demonstrated here that ZIKV replicates in human testicular tissue and infects a broad range of cell types, including germ cells, which we also identified as infected in semen from ZIKV-infected donors. ZIKV had no major deleterious effect on the morphology and hormonal production of the human testis explants. Infection induced a broad antiviral response but no IFN upregulation and minimal proinflammatory response in testis explants, with no cytopathic effect. Finally, we studied ZIKV infection in mouse testis and compared it to human infection. This study provides key insights into how ZIKV may persist in semen and alter semen parameters, as well as a valuable tool for testing antiviral agents.

20.
Brain Pathol ; 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30020561

RESUMO

BACKGROUND: The recent outbreak of Zika virus (ZIKV) infection and the associated increased prevalence of microcephaly in Brazil underline the impact of viral infections on embryo fetal development. The aim of the present study is to provide a detailed clinical and histopathological study of the fetal disruption caused by the ZIKV, with a special focus on the associated neuropathological findings. METHODS: A detailed feto-placental examination, as well as neuropathological and neurobiological studies were performed on three fetuses collected after pregnancy termination between 22 and 25 weeks of gestation (WG), because brain malformations associated with a maternal and fetal ZIKV infection was diagnosed. RESULTS: In all three cases, the maternal infection occurred during the first trimester of pregnancy. A small head was observed on the ultrasound examination of the second trimester of pregnancy and led to the diagnosis of ZIKV fetopathy and pregnancy termination. The fetal histopathological examination was unremarkable on the viscera but showed on the testis an interstitial lymphocytic infiltrate. The placenta contained a Hofbauer cells hyperplasia with signs of inflammation. Neuropathological findings included a meningoencephalitis and an ex vacuo hydrocephalus. Immunohistochemical studies showed the presence of T lymphocytic and histiocytic meningitis associated with an abundant cerebral astroglial and macrophagic reaction. In situ hybridization demonstrated, abundant ZIKV particles within the cerebral parenchyma mainly in the ventricular/subventricular zone and in the cortical plate. In addition massive cells death and endoplasmic reticulum damage were present. CONCLUSION: The present study reports on the clinical and histopathological findings observed in three fetuses infected by the ZIKV. It emphasizes the severity of brain damages and the minimal visceral and placental changes observed upon ZIKV infection. This confirms the selective neurotropism of ZIKV. Finally, it allows us to describe the cascade of multifactorial developmental defects leading to microcephaly.

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