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1.
Lancet Psychiatry ; 8(5): 373-386, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33740410

RESUMO

BACKGROUND: Childhood maltreatment is associated with poor mental and physical health. However, the mechanisms of gene-environment correlations and the potential causal effects of childhood maltreatment on health are unknown. Using genetics, we aimed to delineate the sources of gene-environment correlation for childhood maltreatment and the causal relationship between childhood maltreatment and health. METHODS: We did a genome-wide association study meta-analysis of childhood maltreatment using data from the UK Biobank (n=143 473), Psychiatric Genomics Consortium (n=26 290), Avon Longitudinal Study of Parents and Children (n=8346), Adolescent Brain Cognitive Development Study (n=5400), and Generation R (n=1905). We included individuals who had phenotypic and genetic data available. We investigated single nucleotide polymorphism heritability and genetic correlations among different subtypes, operationalisations, and reports of childhood maltreatment. Family-based and population-based polygenic score analyses were done to elucidate gene-environment correlation mechanisms. We used genetic correlation and Mendelian randomisation analyses to identify shared genetics and test causal relationships between childhood maltreatment and mental and physical health conditions. FINDINGS: Our meta-analysis of genome-wide association studies (N=185 414) identified 14 independent loci associated with childhood maltreatment (13 novel). We identified high genetic overlap (genetic correlations 0·24-1·00) among different maltreatment operationalisations, subtypes, and reporting methods. Within-family analyses provided some support for active and reactive gene-environment correlation but did not show the absence of passive gene-environment correlation. Robust Mendelian randomisation suggested a potential causal role of childhood maltreatment in depression (unidirectional), as well as both schizophrenia and ADHD (bidirectional), but not in physical health conditions (coronary artery disease, type 2 diabetes) or inflammation (C-reactive protein concentration). INTERPRETATION: Childhood maltreatment has a heritable component, with substantial genetic correlations among different operationalisations, subtypes, and retrospective and prospective reports of childhood maltreatment. Family-based analyses point to a role of active and reactive gene-environment correlation, with equivocal support for passive correlation. Mendelian randomisation supports a (primarily bidirectional) causal role of childhood maltreatment on mental health, but not on physical health conditions. Our study identifies research avenues to inform the prevention of childhood maltreatment and its long-term effects. FUNDING: Wellcome Trust, UK Medical Research Council, Horizon 2020, National Institute of Mental Health, and National Institute for Health Research Biomedical Research Centre.


Assuntos
Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Sobreviventes Adultos de Maus-Tratos Infantis/estatística & dados numéricos , Interação Gene-Ambiente , Estudo de Associação Genômica Ampla/métodos , Transtornos Mentais/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bases de Dados Factuais , Europa (Continente) , Feminino , Humanos , Estudos Longitudinais , Masculino , Transtornos Mentais/psicologia , Saúde Mental , Pessoa de Meia-Idade , Estudos Retrospectivos , Reino Unido , Adulto Jovem
2.
Biostatistics ; 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33155035

RESUMO

Valid estimation of a causal effect using instrumental variables requires that all of the instruments are independent of the outcome conditional on the risk factor of interest and any confounders. In Mendelian randomization studies with large numbers of genetic variants used as instruments, it is unlikely that this condition will be met. Any given genetic variant could be associated with a large number of traits, all of which represent potential pathways to the outcome which bypass the risk factor of interest. Such pleiotropy can be accounted for using standard multivariable Mendelian randomization with all possible pleiotropic traits included as covariates. However, the estimator obtained in this way will be inefficient if some of the covariates do not truly sit on pleiotropic pathways to the outcome. We present a method that uses regularization to identify which out of a set of potential covariates need to be accounted for in a Mendelian randomization analysis in order to produce an efficient and robust estimator of a causal effect. The method can be used in the case where individual-level data are not available and the analysis must rely on summary-level data only. It can be used where there are any number of potential pleiotropic covariates up to the number of genetic variants less one. We show the results of simulation studies that demonstrate the performance of the proposed regularization method in realistic settings. We also illustrate the method in an applied example which looks at the causal effect of urate plasma concentration on coronary heart disease.

4.
J R Soc Interface ; 17(168): 20200299, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32634369

RESUMO

Antibiotic therapy has drastically reduced the mortality and sequelae of bacterial infections. From naturally occurring to chemically synthesized, different classes of antibiotics have been successfully used without detailed knowledge of how they affect bacterial dynamics in vivo. However, a proportion of patients receiving antimicrobial therapy develop recrudescent infections post-treatment. Relapsing infections are attributable to incomplete clearance of bacterial populations following antibiotic administration; the metabolic profile of this antibiotic-recalcitrant bacterial subpopulation, the spatio-temporal context of its emergence and the variance of antibiotic-bacterial interactions in vivo remain unclear. Here, we develop and apply a mechanistic mathematical model to data from a study comparing the effects of ciprofloxacin and ampicillin on the within-host dynamics of Salmonella enterica serovar Typhimurium in murine infections. Using the inferential capacity of our model, we show that the antibiotic-recalcitrant bacteria following ampicillin, but not ciprofloxacin, treatment belong to a non-replicating phenotype. Aligning with previous studies, we independently estimate that the lymphoid tissues and spleen are important reservoirs of non-replicating bacteria. Finally, we predict that post-treatment, the progenitors of the non-growing and growing bacterial populations replicate and die at different rates. Ultimately, the liver, spleen and mesenteric lymph nodes are all repopulated by progenitors of the previously non-growing phenotype in ampicillin-treated mice.

5.
Int Rev Psychiatry ; 31(7-8): 613-618, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31638446

RESUMO

Medical students' wellbeing and mental health requires nurturing in order for them to build success in their careers, help people while doing so, and to be happy. To better characterise the current state of wellbeing in medical schools in Wales, medical students from Cardiff and Swansea Universities were asked to complete an online survey as part of a larger international survey regarding their mental health and wellbeing. 266 students responded out of approximately 2150, a rate of 12%. 44 students received a mental health diagnosis whilst at medical school (predominantly depression or anxiety), 65 scored threshold for concerning alcohol consumption using the CAGE questionnaire, and 224 and 230 students reached threshold for the disengagement and exhaustion components of the Oldenburg Burnout Scale, respectively.


Assuntos
Ansiedade/diagnóstico , Esgotamento Profissional/psicologia , Depressão/diagnóstico , Saúde Mental , Estudantes de Medicina/estatística & dados numéricos , Alcoolismo/psicologia , Ansiedade/psicologia , Depressão/psicologia , Feminino , Humanos , Masculino , Faculdades de Medicina , Estudantes de Medicina/psicologia , Inquéritos e Questionários , País de Gales
6.
Int J Food Microbiol ; 277: 41-49, 2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-29680695

RESUMO

Consumer perception of poor hygiene of fresh milk products is a major barrier to promotion of milk consumption as an intervention to alleviate the burden of malnutrition in Ghana. Fresh milk is retailed raw, boiled, or processed into unfermented cheese and spontaneously fermented products in unlicensed outlets. In this study, we have determined microbiological quality of informally retailed fresh milk products and characterized the genomic diversity and antimicrobial resistance (AMR) patterns of non-typhoidal Salmonella (NTS) in implicated products. A total of 159 common dairy products were purchased from five traditional milk markets in Accra. Samples were analysed for concentrations of aerobic bacteria, total and fecal coliforms, Escherichia coli, staphylococci, lactic acid bacteria and yeast and moulds. The presence of Salmonella, E. coli O157:H7, Listeria monocytogenes and Staphylococcus aureus were determined. AMR of Salmonella against 18 antibiotics was experimentally determined. Genome sequencing of 19 Salmonella isolates allowed determination of serovars, antigenic profiles, prediction of AMR genes in silico and inference of phylogenetic relatedness between strains. Raw and heat-treated milk did not differ significantly in overall bacterial quality (P = 0.851). E. coli O157:H7 and Staphylococcus aureus were present in 34.3% and 12.9% of dairy products respectively. Multidrug resistant (MDR) Salmonella enterica serovars Muenster and Legon were identified in 11.8% and 5.9% of unfermented cheese samples respectively. Pan genome analysis revealed a total of 3712 core genes. All Salmonella strains were resistant to Trimethoprim/Sulfamethoxazole, Cefoxitin, Cefuroxime Axetil and Cefuroxime. Resistance to Chloramphenicol (18%) and Ciprofloxacin (100%), which are first line antibiotics used in treatment of NTS bacteremia in Ghana, was evident. AMR was attributed to presence and/or mutations in the following genes: golS, sdiA for cephalosporins, aac(6')-Iy, ant(9) for aminoglycosides, mdtK, gyrA, gyrB, parC, parE for quinolones and cat1, cat4 for phenicols. Phylogenetic analysis based on accessory genes clustered S. Legon strains separately from the S. Muenster strains. These strains were from different markets suggesting local circulation of related strains. Our study justifies consumer resistance to consumption of unripened soft cheese without further lethal heat treatment, and provides evidence that supports the Ghana Health Service recommendation for use of 3rd generation cephalosporins for the treatment of MDR NTS infections.


Assuntos
Queijo/microbiologia , Farmacorresistência Bacteriana , Escherichia coli O157/isolamento & purificação , Listeria monocytogenes/isolamento & purificação , Leite/microbiologia , Salmonella enterica/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Ciprofloxacino/farmacologia , Escherichia coli O157/efeitos dos fármacos , Microbiologia de Alimentos , Gana , Listeria monocytogenes/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Filogenia , Salmonella enterica/classificação , Salmonella enterica/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
7.
PLoS One ; 13(3): e0194481, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29561903

RESUMO

Campylobacter spp. are a leading cause of bacterial enteritis worldwide, including countries in Africa, and have been identified by the World Health Organisation (WHO) as one of the high priority antimicrobial resistant pathogens. However, at present there is little knowledge on the prevalence, molecular epidemiology or antimicrobial susceptibility of Campylobacter spp. isolates in Botswana, both in patients and in the zoonotic context. Some data indicate that ~14% of diarrhoeal disease cases in a paediatric setting can be ascribed to Campylobacter spp., urging the need for the magnitude of Campylobacter-associated diarrhoea to be established. In this survey, we have characterised the genomic diversity of Campylobacter spp. circulating in Botswana isolated from cases of diarrhoeal disease in humans (n = 20) and from those that colonised commercial broiler (n = 35) and free-range (n = 35) chickens. Phylogeny showed that the Campylobacter spp. isolated from the different poultry and human sources were highly related, suggesting that zoonotic transmission has likely occurred. We found that for Campylobacter spp. isolated from humans, broilers and free-range chickens, 52% was positive for tetO, 47% for gyrA-T86I, 72% for blaOXA-61, with 27% carrying all three resistance determinants. No 23S mutations conferring macrolide resistance were detected in this survey. In summary, our study provides insight into Campylobacter spp. in poultry reservoirs and in diarrhoeal patients, and the relevance for treatment regimens in Botswana.


Assuntos
Infecções por Campylobacter , Campylobacter , Galinhas/microbiologia , Diarreia , Farmacorresistência Bacteriana , Filogenia , Doenças das Aves Domésticas , Animais , Botsuana , Campylobacter/genética , Campylobacter/isolamento & purificação , Infecções por Campylobacter/genética , Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/veterinária , Diarreia/genética , Diarreia/microbiologia , Diarreia/veterinária , Feminino , Humanos , Masculino , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/microbiologia
8.
Int J Syst Evol Microbiol ; 68(1): 21-27, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29099353

RESUMO

Here we describe a new species of the genus Streptococcus that was isolated from a dairy cow with mastitis in New Zealand. Strain NZ1587T was Gram-positive, coccus-shaped and arranged as chains, catalase and coagulase negative, γ-haemolytic and negative for Lancefield carbohydrates (A-D, F and G). The 16S rRNA sequence did not match sequences in the NCBI 16S rRNA or GreenGenes databases. Taxonomic classification of strain NZ1587T was investigated using 16S rRNA and core genome phylogeny, genome-wide average nucleotide identity (ANI) and predicted DNA-DNA hybridisation (DDH) analyses. Phylogeny based on 16S rRNA was unable to resolve the taxonomic position of strain NZ1587T, however NZ1587T shared 99.4 % identity at the 16S rRNA level with a distinct branch of S. pseudoporcinus. Importantly, core genome phylogeny demonstrated that NZ1587T grouped amongst the 'pyogenic' streptococcal species and formed a distinct branch supported by a 100 % bootstrap value. In addition, average nucleotide identity and inferred DNA-DNA hybridisation analyses showed that NZ1587T represents a novel species. Biochemical profiling using the rapid ID 32 strep identification test enabled differentiation of strain NZ1587T from closely related streptococcal species. In conclusion, strain NZ1587T can be classified as a novel species, and we propose a novel taxon named Streptococcus bovimastitidis sp. nov.; the type strain is NZ1587T. NZ1587T has been deposited in the Culture Collection University of Gothenburg (CCUG 69277T) and the Belgian Co-ordinated Collections of Micro-organisms/LMG (LMG 29747).


Assuntos
Mastite Bovina/microbiologia , Filogenia , Infecções Estreptocócicas/veterinária , Streptococcus/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Feminino , Nova Zelândia , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptococcus/genética , Streptococcus/isolamento & purificação
9.
Genome Announc ; 5(38)2017 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-28935722

RESUMO

We present single-contig assemblies for Escherichia coli strain KV7 (serotype O27, phylogenetic group D) and its six plasmids, isolated from a healthy pig, as determined by PacBio RS II and Illumina MiSeq sequencing. The chromosome of 4,997,475 bp and G+C content of 50.75% harbored 4,540 protein-encoding genes.

10.
PLoS One ; 12(8): e0181365, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28796780

RESUMO

Salmonella enterica are a threat to public health. Current vaccines are not fully effective. The ability to grow in infected tissues within phagocytes is required for S. enterica virulence in systemic disease. As the infection progresses the bacteria are exposed to a complex host immune response. Consequently, in order to continue growing in the tissues, S. enterica requires the coordinated regulation of fitness genes. Bacterial gene regulation has so far been investigated largely using exposure to artificial environmental conditions or to in vitro cultured cells, and little information is available on how S. enterica adapts in vivo to sustain cell division and survival. We have studied the transcriptome, proteome and metabolic flux of Salmonella, and the transcriptome of the host during infection of wild type C57BL/6 and immune-deficient gp91-/-phox mice. Our analyses advance the understanding of how S. enterica and the host behaves during infection to a more sophisticated level than has previously been reported.


Assuntos
Proteínas de Bactérias/genética , Proteoma/genética , Salmonelose Animal/genética , Salmonelose Animal/microbiologia , Salmonella typhimurium/genética , Transcriptoma , Animais , Proteínas de Bactérias/análise , Feminino , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteoma/análise , Receptores Imunológicos/análise , Receptores Imunológicos/genética
11.
Sci Rep ; 7(1): 1251, 2017 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-28455506

RESUMO

Campylobacter is the most common cause of foodborne bacterial illness worldwide. Faecal contamination of meat, especially chicken, during processing represents a key route of transmission to humans. There is a lack of insight into the mechanisms driving C. jejuni growth and survival within hosts and the environment. Here, we report a detailed analysis of C. jejuni fitness across models reflecting stages in its life cycle. Transposon (Tn) gene-inactivation libraries were generated in three C. jejuni strains and the impact on fitness during chicken colonisation, survival in houseflies and under nutrient-rich and -poor conditions at 4 °C and infection of human gut epithelial cells was assessed by Tn-insertion site sequencing (Tn-seq). A total of 331 homologous gene clusters were essential for fitness during in vitro growth in three C. jejuni strains, revealing that a large part of its genome is dedicated to growth. We report novel C. jejuni factors essential throughout its life cycle. Importantly, we identified genes that fulfil important roles across multiple conditions. Our comprehensive screens showed which flagella elements are essential for growth and which are vital to the interaction with host organisms. Future efforts should focus on how to exploit this knowledge to effectively control infections caused by C. jejuni.


Assuntos
Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/veterinária , Campylobacter jejuni/crescimento & desenvolvimento , Campylobacter jejuni/genética , Aptidão Genética , Genoma Bacteriano , Animais , Linhagem Celular , Galinhas , Meios de Cultura/química , Células Epiteliais/microbiologia , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Moscas Domésticas , Humanos , Viabilidade Microbiana , Mutagênese Insercional , Temperatura
12.
Sci Rep ; 7: 44283, 2017 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-28281647

RESUMO

To investigate how Campylobacter jejuni causes the clinical symptoms of diarrhoeal disease in humans, use of a relevant animal model is essential. Such a model should mimic the human disease closely in terms of host physiology, incubation period before onset of disease, clinical signs and a comparable outcome of disease. In this study, we used a gnotobiotic piglet model to study determinants of pathogenicity of C. jejuni. In this model, C. jejuni successfully established infection and piglets developed an increased temperature with watery diarrhoea, which was caused by a leaky epithelium and reduced bile re-absorption in the intestines. Further, we assessed the C. jejuni genes required for infection of the porcine gastrointestinal tract utilising a transposon (Tn) mutant library screen. A total of 123 genes of which Tn mutants showed attenuated piglet infection were identified. Our screen highlighted a crucial role for motility and chemotaxis, as well as central metabolism. In addition, Tn mutants of 14 genes displayed enhanced piglet infection. This study gives a unique insight into the mechanisms of C. jejuni disease in terms of host physiology and contributing bacterial factors.


Assuntos
Infecções por Campylobacter/veterinária , Campylobacter jejuni/genética , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano/genética , Animais , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/patogenicidade , Elementos de DNA Transponíveis/genética , Modelos Animais de Doenças , Trato Gastrointestinal/microbiologia , Vida Livre de Germes , Humanos , Mutagênese Insercional , Suínos , Doenças dos Suínos/microbiologia , Virulência/genética
13.
Pathog Dis ; 75(1)2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28087648

RESUMO

Immunity can co-operate with antibiotics, but can also antagonize drug efficacy by segregating the bacteria to areas of the body that are less accessible to antimicrobials, and by selecting for subpopulations with low division rates that are often difficult to eradicate. We studied the effect of an anti-inflammatory/immunosuppressive anti-TNFα treatment, which accelerates bacterial growth in the tissues and inhibits or reverses the formation of granulomas, on the efficacy of ampicillin and ciprofloxacin during a systemic Salmonella enterica infection of the mouse. The anti-TNFα treatment neither precluded nor enhanced the efficacy of antibiotic treatment. However, the anti-TNFα treatment rendered the animals susceptible to the rapid relapse of the infection seen after cessation of the antibiotic treatment. Reactivation of an established infection, due to late administration of anti-TNFα antibodies, could be successfully controlled by antibiotics, but full clearance of the bacterial load from the tissues was not achieved. We conclude that the lack of TNFα does not preclude the efficacy of antibiotic treatment and must be monitored with care due to post-treatment relapses. Combinations of anti-cytokine compounds and antibiotic molecules may not be the best way to treat persistent infections with intracellular bacteria like Salmonella.


Assuntos
Antibacterianos/farmacologia , Infecções por Salmonella/metabolismo , Infecções por Salmonella/microbiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/fisiologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Feminino , Imunossupressores/farmacologia , Fígado/imunologia , Fígado/metabolismo , Fígado/microbiologia , Fígado/patologia , Camundongos , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/imunologia , Baço/imunologia , Baço/metabolismo , Baço/microbiologia , Baço/patologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/farmacologia
14.
Microb Pathog ; 104: 202-211, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28131954

RESUMO

Campylobacter jejuni is the leading cause of bacterial food borne illness. While helical cell shape is considered important for C. jejuni pathogenesis, this bacterium is capable of adopting other morphologies. To better understand how helical-shaped C. jejuni maintain their shape and thus any associated colonisation, pathogenicity or other advantage, it is first important to identify the genes and proteins involved. So far, two peptidoglycan modifying enzymes Pgp1 and Pgp2 have been shown to be required for C. jejuni helical cell shape. We performed a visual screen of ∼2000 transposon mutants of C. jejuni for cell shape mutants. Whole genome sequence data of the mutants with altered cell shape, directed mutants, wild type stocks and isolated helical and rod-shaped 'wild type' C. jejuni, identified a number of different mutations in pgp1 and pgp2, which result in a change in helical to rod bacterial cell shape. We also identified an isolate with a loss of curvature. In this study, we have identified the genomic change in this isolate, and found that targeted deletion of the gene with the change resulted in bacteria with loss of curvature. Helical cell shape was restored by supplying the gene in trans. We examined the effect of loss of the gene on bacterial motility, adhesion and invasion of tissue culture cells and chicken colonisation, as well as the effect on the muropeptide profile of the peptidoglycan sacculus. Our work identifies another factor involved in helical cell shape.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Campylobacter jejuni/citologia , Campylobacter jejuni/genética , Aderência Bacteriana , Células CACO-2 , Campylobacter jejuni/fisiologia , Parede Celular/metabolismo , Elementos de DNA Transponíveis , Endocitose , Deleção de Genes , Teste de Complementação Genética , Humanos , Locomoção , Mutagênese Insercional , Peptidoglicano/metabolismo
15.
Sci Rep ; 6: 38303, 2016 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-27910897

RESUMO

Campylobacter jejuni, the most common cause of bacterial diarrhoeal disease, is normally helical. However, it can also adopt straight rod, elongated helical and coccoid forms. Studying how helical morphology is generated, and how it switches between its different forms, is an important objective for understanding this pathogen. Here, we aimed to determine the genetic factors involved in generating the helical shape of Campylobacter. A C. jejuni transposon (Tn) mutant library was screened for non-helical mutants with inconsistent results. Whole genome sequence variation and morphological trends within this Tn library, and in various C. jejuni wild type strains, were compared and correlated to detect genomic elements associated with helical and rod morphologies. All rod-shaped C. jejuni Tn mutants and all rod-shaped laboratory, clinical and environmental C. jejuni and Campylobacter coli contained genetic changes within the pgp1 or pgp2 genes, which encode peptidoglycan modifying enzymes. We therefore confirm the importance of Pgp1 and Pgp2 in the maintenance of helical shape and extended this to a wide range of C. jejuni and C. coli isolates. Genome sequence analysis revealed variation in the sequence and length of homopolymeric tracts found within these genes, providing a potential mechanism of phase variation of cell shape.


Assuntos
Proteínas de Bactérias/genética , Infecções por Campylobacter/veterinária , Campylobacter coli/genética , Campylobacter jejuni/genética , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Doenças das Aves Domésticas/microbiologia , Animais , Proteínas de Bactérias/metabolismo , Infecções por Campylobacter/microbiologia , Campylobacter coli/metabolismo , Campylobacter coli/ultraestrutura , Campylobacter jejuni/metabolismo , Campylobacter jejuni/ultraestrutura , Galinhas , Elementos de DNA Transponíveis , Biblioteca Gênica , Humanos , Mutagênese Sítio-Dirigida , Mutação , Peptidoglicano/biossíntese , Peptidoglicano/genética , Sequenciamento Completo do Genoma
16.
Appl Environ Microbiol ; 82(22): 6664-6671, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27590816

RESUMO

The interior of plants contains microorganisms (referred to as endophytes) that are distinct from those present at the root surface or in the surrounding soil. Herbaspirillum seropedicae strain SmR1, belonging to the betaproteobacteria, is an endophyte that colonizes crops, including rice, maize, sugarcane, and sorghum. Different approaches have revealed genes and pathways regulated during the interactions of H. seropedicae with its plant hosts. However, functional genomic analysis of transposon (Tn) mutants has been hampered by the lack of genetic tools. Here we successfully employed a combination of in vivo high-density mariner Tn mutagenesis and targeted Tn insertion site sequencing (Tn-seq) in H. seropedicae SmR1. The analysis of multiple gene-saturating Tn libraries revealed that 395 genes are essential for the growth of H. seropedicae SmR1 in tryptone-yeast extract medium. A comparative analysis with the Database of Essential Genes (DEG) showed that 25 genes are uniquely essential in H. seropedicae SmR1. The Tn mutagenesis protocol developed and the gene-saturating Tn libraries generated will facilitate elucidation of the genetic mechanisms of the H. seropedicae endophytic lifestyle. IMPORTANCE: A focal point in the study of endophytes is the development of effective biofertilizers that could help to reduce the input of agrochemicals in croplands. Besides the ability to promote plant growth, a good biofertilizer should be successful in colonizing its host and competing against the native microbiota. By using a systematic Tn-based gene-inactivation strategy and massively parallel sequencing of Tn insertion sites (Tn-seq), it is possible to study the fitness of thousands of Tn mutants in a single experiment. We have applied the combination of these techniques to the plant-growth-promoting endophyte Herbaspirillum seropedicae SmR1. The Tn mutant libraries generated will enable studies into the genetic mechanisms of H. seropedicae-plant interactions. The approach that we have taken is applicable to other plant-interacting bacteria.


Assuntos
Elementos de DNA Transponíveis/genética , Endófitos/genética , Genes Bacterianos , Herbaspirillum/genética , Produtos Agrícolas/microbiologia , Meios de Cultura , Endófitos/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Genes Essenciais , Herbaspirillum/crescimento & desenvolvimento , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Mutagênese Insercional
17.
J Vaccines Vaccin ; 7(3)2016 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-27366588

RESUMO

Invasive non-typhoidal Salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. Multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. Flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. We examined the effect of targeting flagella with different classes of IgG on the interaction between Salmonella Typhimurium and a human phagocyte-like cell line, THP-1. We tagged the FliC flagellar protein with a foreign CD52 mimotope (TSSPSAD) and bacteria were opsonized with a panel of humanised CD52 antibodies with the same antigen-binding V-region, but different constant regions. We found that IgG binding to flagella increases bacterial phagocytosis and reduces viable intracellular bacterial numbers. Opsonisation with IgG3, followed by IgG1, IgG4, and IgG2, resulted in the highest level of bacterial uptake and in the highest reduction in the intracellular load of viable bacteria. Taken together, our data provide proof-of-principle evidence that targeting flagella with antibodies can increase the antibacterial function of host cells, with IgG3 being the most potent subclass. These data will assist the rational design of urgently needed, optimised vaccines against iNTS disease.

18.
J Clin Immunol ; 36(6): 571-82, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27220317

RESUMO

PURPOSE: Treatment of primary immunodeficiency diseases (PIDD) with subcutaneous (SC) infusions of IgG preceded by injection of recombinant human hyaluronidase (rHuPH20) (IGHy) to increase SC tissue permeability was evaluated in two consecutive, prospective, non-controlled, multi-center studies. METHODS: Subjects >4 years of age received SC IgG replacement at a weekly dose equivalent of 108 % of their previous intravenous (IV) dose, facilitated by prior injection of 75 U/g IgG of rHuPH20. Starting with weekly SC infusions, the interval was increased (ramped-up) to a 3- or 4-week schedule. RESULTS: Eighty-three subjects (24 < 18 years; 59 ≥ 18 years) received 2729 infusions (excluding ramp-up) at a mean dose of 0.155 g/kg/week in the pivotal and 0.156 g/kg/week in the extension study. IGHy exposure exceeded 30 months in 48 subjects. During 187.7 subject-years of IGHy exposure, 2005 adverse events (AEs) (10.68 per subject-year) occurred. The rate of related systemic AEs during consecutive 1-year periods remained low; the rate of related local AEs decreased from 3.68/subject-year in months 1-12 to approximately 1.50/subject-year after 30 months of treatment. Fifteen subjects transiently developed anti-rHuPH20 binding antibody. There was no difference in AE rates in these subjects before and after the first titer increase to ≥1:160. The rate of infections during IGHy exposure was 2.99 per subject-year and did not increase during the studies. Annual infection rates were 3.02 in subjects <18 years and 2.98 in subjects ≥18 years. CONCLUSIONS: Long-term replacement therapy with IGHy was safe and effective in 83 pediatric and adult subjects with PIDD.


Assuntos
Hialuronoglucosaminidase/administração & dosagem , Imunoglobulinas Intravenosas/administração & dosagem , Síndromes de Imunodeficiência/tratamento farmacológico , Proteínas Recombinantes/administração & dosagem , Adolescente , Adulto , Idoso , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/etiologia , Criança , Feminino , Hospitalização , Humanos , Hialuronoglucosaminidase/efeitos adversos , Imunoglobulinas Intravenosas/efeitos adversos , Infusões Subcutâneas , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/efeitos adversos , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
20.
Infect Immun ; 84(4): 989-997, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26787719

RESUMO

Salmonella enterica causes systemic diseases (typhoid and paratyphoid fever), nontyphoidal septicemia (NTS), and gastroenteritis in humans and other animals worldwide. An important but underrecognized emerging infectious disease problem in sub-Saharan Africa is NTS in children and immunocompromised adults. A current goal is to identify Salmonella mutants that are not pathogenic in the absence of key components of the immune system such as might be found in immunocompromised hosts. Such attenuated strains have the potential to be used as live vaccines. We have used transposon-directed insertion site sequencing (TraDIS) to screen mutants of Salmonella enterica serovar Typhimurium for their ability to infect and grow in the tissues of wild-type and immunodeficient mice. This was to identify bacterial genes that might be deleted for the development of live attenuated vaccines that would be safer to use in situations and/or geographical areas where immunodeficiencies are prevalent. The relative fitness of each of 9,356 transposon mutants, representing mutations in 3,139 different genes, was determined in gp91(-/-) phox mice. Mutations in certain genes led to reduced fitness in both wild-type and mutant mice. To validate these results, these genes were mutated by allelic replacement, and resultant mutants were retested for fitness in the mice. A defined deletion mutant of cysE was attenuated in C57BL/6 wild-type mice and immunodeficient gp91(-/-) phox mice and was effective as a live vaccine in wild-type mice.


Assuntos
Glicoproteínas de Membrana/metabolismo , NADPH Oxidases/metabolismo , Salmonelose Animal/microbiologia , Salmonella typhimurium/patogenicidade , Alelos , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Vacinas Bacterianas/imunologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Hospedeiro Imunocomprometido , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , NADPH Oxidase 2 , NADPH Oxidases/genética , Salmonelose Animal/imunologia , Salmonelose Animal/prevenção & controle , Virulência
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