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1.
PLoS Genet ; 18(3): e1009776, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35286304

RESUMO

Shotgun metagenomics is a powerful tool to identify antimicrobial resistance (AMR) genes in microbiomes but has the limitation that extrachromosomal DNA, such as plasmids, cannot be linked with the host bacterial chromosome. Here we present a comprehensive laboratory and bioinformatics pipeline HAM-ART (Hi-C Assisted Metagenomics for Antimicrobial Resistance Tracking) optimised for the generation of metagenome-assembled genomes including both chromosomal and extrachromosomal AMR genes. We demonstrate the performance of the pipeline in a study comparing 100 pig faecal microbiomes from low- and high-antimicrobial use pig farms (organic and conventional farms). We found significant differences in the distribution of AMR genes between low- and high-antimicrobial use farms including a plasmid-borne lincosamide resistance gene exclusive to high-antimicrobial use farms in three species of Lactobacilli. The bioinformatics pipeline code is available at https://github.com/lkalmar/HAM-ART.


Assuntos
Anti-Infecciosos , Microbiota , Animais , Antibacterianos , Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana/genética , Metagenômica , Suínos
2.
Avian Pathol ; 49(6): 666-677, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32907345

RESUMO

A novel inactivated vaccine, comprising three serovars of Salmonella enterica (Enteritidis, serogroup O:9; Typhimurium, serogroup O:4; Infantis, serogroup O:7) grown under conditions of iron restriction and adjuvanted with aluminium hydroxide, was evaluated for efficacy following challenge by homologous and heterologous serovars. Chickens were vaccinated at 6 and 10 weeks of age by the intramuscular route and challenged 4 to 9 weeks after the second vaccination with serovars belonging to serogroup O:9 (Enteritidis), O:4 (Typhimurium and Heidelberg), O:7 (Infantis and Virchow), and O:8 (Hadar). All vaccinated birds produced a marked systemic antibody response against each of the component vaccine antigens by the time of challenge. Significant reductions in both colonization of the intestinal tract and invasion of internal organs were observed in vaccinated birds compared with non-vaccinated controls, irrespective of the challenge serovar. The findings suggest that broad serovar protection within the constitutive serogroups of an inactivated multi-valent vaccine is possible and could, therefore, play an important role in future Salmonella control programmes. RESEARCH HIGHLIGHTS Novel inactivated trivalent Salmonella chicken vaccine was developed and tested. Vaccine induced marked systemic antibody response against all vaccine antigens. Significant reductions in intestinal tract colonization and internal organ invasion. Vaccine efficacy demonstrated against homologous and heterologous serovars.


Assuntos
Galinhas/imunologia , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/prevenção & controle , Vacinas contra Salmonella/imunologia , Salmonella enterica/imunologia , Vacinação/veterinária , Animais , Galinhas/microbiologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Sorogrupo , Vacinas de Produtos Inativados
3.
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
4.
Environ Microbiol ; 19(1): 361-380, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27883255

RESUMO

Campylobacter jejuni is a major cause of bacterial gastroenteritis worldwide, primarily associated with the consumption of contaminated poultry. C. jejuni lineages vary in host range and prevalence in human infection, suggesting differences in survival throughout the poultry processing chain. From 7343 MLST-characterised isolates, we sequenced 600 C. jejuni and C. coli isolates from various stages of poultry processing and clinical cases. A genome-wide association study (GWAS) in C. jejuni ST-21 and ST-45 complexes identified genetic elements over-represented in clinical isolates that increased in frequency throughout the poultry processing chain. Disease-associated SNPs were distinct in these complexes, sometimes organised in haplotype blocks. The function of genes containing associated elements was investigated, demonstrating roles for cj1377c in formate metabolism, nuoK in aerobic survival and oxidative respiration, and cj1368-70 in nucleotide salvage. This work demonstrates the utility of GWAS for investigating transmission in natural zoonotic pathogen populations and provides evidence that major C. jejuni lineages have distinct genotypes associated with survival, within the host specific niche, from farm to fork.


Assuntos
Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/veterinária , Campylobacter jejuni/genética , Campylobacter jejuni/isolamento & purificação , Doenças das Aves Domésticas/microbiologia , Animais , Campylobacter jejuni/classificação , Campylobacter jejuni/crescimento & desenvolvimento , Fazendas , Genoma Bacteriano , Genótipo , Humanos , Tipagem de Sequências Multilocus , Fenótipo , Aves Domésticas
5.
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
6.
Mol Microbiol ; 91(3): 522-37, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24344868

RESUMO

The complement system is an important innate defence mechanism, and the ability to resist complement-mediated killing is considered a key virulence trait of the respiratory tract pathogen M. catarrhalis. We studied the molecular basis of complement resistance by transcriptional profiling and Tn-seq, a genome-wide negative-selection screenings technology. Exposure of M. catarrhalis to human serum resulted in increased expression of 84 genes and reduced expression of 134 genes, among which genes encoding ABC transporter systems and surface proteins UspA1 and McaP. By subjecting a ∼ 15 800 transposon mutant library to serum, mutants of 53 genes were negatively selected, including the key complement-resistance factor uspA2H. Validation with directed mutants confirmed Tn-seq phenotypes of uspA2H and 11 newly identified genes, with mutants of MCR_0424, olpA, MCR_1483, and dsbB most severely attenuated. Detailed analysis showed that both components of the disulphide bond formation (DSB) system, DsbB and DsbA, were required for complement-resistance in multiple isolates, and fulfil a critical role in evasion of IgG-dependent classical pathway-mediated killing. Lipooligosaccharide (LOS) structure and membrane stability were severely affected in ΔdsbA strains, suggesting a pivotal role for the DSB system in LOS structure safeguarding and membrane stability maintenance.


Assuntos
Proteínas do Sistema Complemento/imunologia , Dissulfetos/metabolismo , Moraxella catarrhalis/enzimologia , Moraxella catarrhalis/imunologia , Oxirredutases/metabolismo , Fatores de Virulência/metabolismo , Atividade Bactericida do Sangue , Perfilação da Expressão Gênica , Humanos , Dados de Sequência Molecular , Moraxella catarrhalis/genética , Moraxella catarrhalis/metabolismo , Mutagênese Insercional , Oxirredutases/genética , Análise de Sequência de DNA , Fatores de Virulência/genética
7.
Microbiology (Reading) ; 161(12): 2316-27, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26385289

RESUMO

Genetic variation due to mutation and phase variation has a considerable impact on the commensal and pathogenic behaviours of Campylobacter jejuni. In this study, we provide an example of how second-site mutations can interfere with gene function analysis in C. jejuni. Deletion of the flagellin B gene (flaB) in C. jejuni M1 resulted in mutant clones with inconsistent motility phenotypes. From the flaB mutant clones picked for further analysis, two were motile, one showed intermediate motility and two displayed severely attenuated motility. To determine the molecular basis of this differential motility, a genome resequencing approach was used. Second-site mutations were identified in the severely attenuated and intermediate motility flaB mutant clones: a TA-dinucleotide deletion in fliW and an A deletion in flgD, respectively. Restoration of WT fliW, using a newly developed genetic complementation system, confirmed that the second-site fliW mutation caused the motility defect as opposed to the primary deletion of flaB. This study highlights the importance of (i) screening multiple defined gene deletion mutant clones, (ii) genetic complementation of the gene deletion and ideally (iii) screening for second-site mutations that might interfere with the pathways/mechanisms under study.


Assuntos
Campylobacter jejuni/citologia , Campylobacter jejuni/genética , Deleção de Sequência , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Campylobacter jejuni/metabolismo , Deleção de Genes , Regulação Bacteriana da Expressão Gênica
8.
BMC Genomics ; 15: 958, 2014 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-25373505

RESUMO

BACKGROUND: Bacterial respiratory tract infections, mainly caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are among the leading causes of global mortality and morbidity. Increased resistance of these pathogens to existing antibiotics necessitates the search for novel targets to develop potent antimicrobials. RESULT: Here, we report a proof of concept study for the reliable identification of potential drug targets in these human respiratory pathogens by combining high-density transposon mutagenesis, high-throughput sequencing, and integrative genomics. Approximately 20% of all genes in these three species were essential for growth and viability, including 128 essential and conserved genes, part of 47 metabolic pathways. By comparing these essential genes to the human genome, and a database of genes from commensal human gut microbiota, we identified and excluded potential drug targets in respiratory tract pathogens that will have off-target effects in the host, or disrupt the natural host microbiota. We propose 249 potential drug targets, 67 of which are targets for 75 FDA-approved antimicrobials and 35 other researched small molecule inhibitors. Two out of four selected novel targets were experimentally validated, proofing the concept. CONCLUSION: Here we have pioneered an attempt in systematically combining the power of high-density transposon mutagenesis, high-throughput sequencing, and integrative genomics to discover potential drug targets at genome-scale. By circumventing the time-consuming and expensive laboratory screens traditionally used to select potential drug targets, our approach provides an attractive alternative that could accelerate the much needed discovery of novel antimicrobials.


Assuntos
Anti-Infecciosos/farmacologia , Bactérias/genética , Genes Essenciais , Bactérias/efeitos dos fármacos , Linhagem Celular , Sequência Conservada/genética , Elementos de DNA Transponíveis/genética , Trato Gastrointestinal/imunologia , Humanos , Redes e Vias Metabólicas/genética , Testes de Sensibilidade Microbiana , Microbiota , Anotação de Sequência Molecular , Família Multigênica , Fases de Leitura Aberta/genética , Reprodutibilidade dos Testes , Frações Subcelulares/metabolismo
9.
Mol Microbiol ; 87(1): 14-29, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23163337

RESUMO

Iron sequestration by the human host is a first line defence against respiratory pathogens like Moraxella catarrhalis, which consequently experiences a period of iron starvation during colonization. We determined the genetic requirements for M. catarrhalis BBH18 growth during iron starvation using the high-throughput genome-wide screening technology genomic array footprinting (GAF). By subjecting a large random transposon mutant library to growth under iron-limiting conditions, mutants of the MCR_0996-rhlB-yggW operon, rnd, and MCR_0457 were negatively selected. Growth experiments using directed mutants confirmed the GAF phenotypes with ΔyggW (putative haem-shuttling protein) and ΔMCR_0457 (hypothetical protein) most severely attenuated during iron starvation, phenotypes which were restored upon genetic complementation of the deleted genes. Deletion of yggW resulted in similar attenuated phenotypes in three additional strains. Transcriptional profiles of ΔyggW and ΔMCR_0457 were highly altered with 393 and 192 differentially expressed genes respectively. In all five mutants, expression of nitrate reductase genes was increased and of nitrite reductase decreased, suggesting an impaired aerobic respiration. Alteration of iron metabolism may affect nasopharyngeal colonization as adherence of all mutants to respiratory tract epithelial cells was attenuated. In conclusion, we elucidated the genetic requirements for M. catarrhalis growth during iron starvation and characterized the roles of the identified genes in bacterial growth and host interaction.


Assuntos
Ferro/metabolismo , Moraxella catarrhalis/crescimento & desenvolvimento , Moraxella catarrhalis/metabolismo , Deleção de Genes , Perfilação da Expressão Gênica , Humanos , Análise em Microsséries , Moraxella catarrhalis/genética , Fenótipo , Transdução de Sinais
10.
Gut Microbes ; 15(1): 2190303, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36951510

RESUMO

Enterohemorrhagic Escherichia coli (EHEC) is a major cause of severe bloody diarrhea, with potentially lethal complications, such as hemolytic uremic syndrome. In humans, EHEC colonizes the colon, which is also home to a diverse community of trillions of microbes known as the gut microbiota. Although these microbes and the metabolites that they produce represent an important component of EHEC's ecological niche, little is known about how EHEC senses and responds to the presence of gut microbiota metabolites. In this study, we used a combined RNA-Seq and Tn-Seq approach to characterize EHEC's response to metabolites from an in vitro culture of 33 human gut microbiota isolates (MET-1), previously demonstrated to effectively resolve recurrent Clostridioides difficile infection in human patients. Collectively, the results revealed that EHEC adjusts to growth in the presence of microbiota metabolites in two major ways: by altering its metabolism and by activating stress responses. Metabolic adaptations to the presence of microbiota metabolites included increased expression of systems for maintaining redox balance and decreased expression of biotin biosynthesis genes, reflecting the high levels of biotin released by the microbiota into the culture medium. In addition, numerous genes related to envelope and oxidative stress responses (including cpxP, spy, soxS, yhcN, and bhsA) were upregulated during EHEC growth in a medium containing microbiota metabolites. Together, these results provide insight into the molecular mechanisms by which pathogens adapt to the presence of competing microbes in the host environment, which ultimately may enable the development of therapies to enhance colonization resistance and prevent infection.


Assuntos
Escherichia coli Êntero-Hemorrágica , Infecções por Escherichia coli , Microbioma Gastrointestinal , Microbiota , Humanos , Escherichia coli Êntero-Hemorrágica/genética , Biotina/metabolismo , Colo
11.
J Bacteriol ; 194(24): 6969, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23209224

RESUMO

Here we report the annotated genome sequence of Moraxella catarrhalis strain RH4, a seroresistant-lineage strain isolated from the blood of an infected patient. This genome sequence will allow us to gain further insight into the genetic diversity of clinical M. catarrhalis isolates and will facilitate study of M. catarrhalis pathogenesis.


Assuntos
Genoma Bacteriano , Moraxella catarrhalis/genética , Composição de Bases/genética , Sequência de Bases , Sangue/microbiologia , DNA Bacteriano/genética , Variação Genética , Humanos , Dados de Sequência Molecular , Moraxella catarrhalis/isolamento & purificação , Infecções por Moraxellaceae/microbiologia , Análise de Sequência de DNA , Escarro/microbiologia , beta-Lactamases/genética
12.
Cell Microbiol ; 13(3): 432-49, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21044239

RESUMO

Moraxella catarrhalis is an emerging human respiratory pathogen in patients with chronic obstructive pulmonary disease (COPD) and in children with acute otitis media. The specific secretion machinery known as outer membrane vesicles (OMVs) is a mechanism by which Gram-negative pathogens interact with host cells during infection. We identified 57 proteins in M. catarrhalis OMVs using a proteomics approach combining two-dimensional SDS-PAGE and MALDI-TOF mass spectrometry analysis. The OMVs contained known surface proteins such as ubiquitous surface proteins (Usp) A1/A2, and Moraxella IgD-binding protein (MID). Most of the proteins are adhesins/virulence factors triggering the immune response, but also aid bacteria to evade the host defence. FITC-stained OMVs bound to lipid raft domains in alveolar epithelial cells and were internalized after interaction with Toll-like receptor 2 (TLR2), suggesting a delivery to the host tissue of a large and complex group of OMV-attributed proteins. Interestingly, OMVs modulated the pro-inflammatory response in epithelial cells, and UspA1-bearing OMVs were found to specifically downregulate the reaction. When mice were exposed to OMVs, a pulmonary inflammation was clearly seen. Our findings indicate that Moraxella OMVs are highly biologically active, transport main bacterial virulence factors and may modulate the epithelial pro-inflammatory response.


Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Células Epiteliais/microbiologia , Inflamação , Moraxella catarrhalis/imunologia , Moraxella catarrhalis/metabolismo , Adesinas Bacterianas/imunologia , Animais , Aderência Bacteriana , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/imunologia , Células Epiteliais/fisiologia , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/metabolismo , Humanos , Pulmão/imunologia , Microdomínios da Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica , Reação em Cadeia da Polimerase , Proteoma , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Coloração e Rotulagem , Receptor 2 Toll-Like/imunologia
13.
BMC Genomics ; 12: 70, 2011 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-21269504

RESUMO

BACKGROUND: M. catarrhalis is a gram-negative, gamma-proteobacterium and an opportunistic human pathogen associated with otitis media (OM) and exacerbations of chronic obstructive pulmonary disease (COPD). With direct and indirect costs for treating these conditions annually exceeding $33 billion in the United States alone, and nearly ubiquitous resistance to beta-lactam antibiotics among M. catarrhalis clinical isolates, a greater understanding of this pathogen's genome and its variability among isolates is needed. RESULTS: The genomic sequences of ten geographically and phenotypically diverse clinical isolates of M. catarrhalis were determined and analyzed together with two publicly available genomes. These twelve genomes were subjected to detailed comparative and predictive analyses aimed at characterizing the supragenome and understanding the metabolic and pathogenic potential of this species. A total of 2383 gene clusters were identified, of which 1755 are core with the remaining 628 clusters unevenly distributed among the twelve isolates. These findings are consistent with the distributed genome hypothesis (DGH), which posits that the species genome possesses a far greater number of genes than any single isolate. Multiple and pair-wise whole genome alignments highlight limited chromosomal re-arrangement. CONCLUSIONS: M. catarrhalis gene content and chromosomal organization data, although supportive of the DGH, show modest overall genic diversity. These findings are in stark contrast with the reported heterogeneity of the species as a whole, as wells as to other bacterial pathogens mediating OM and COPD, providing important insight into M. catarrhalis pathogenesis that will aid in the development of novel therapeutic regimens.


Assuntos
Genoma Bacteriano , Moraxella catarrhalis/genética , Técnicas de Tipagem Bacteriana , Códon , DNA Bacteriano/genética , Sequências Repetitivas Dispersas , Modelos Genéticos , Moraxella catarrhalis/isolamento & purificação , Família Multigênica , Tipagem de Sequências Multilocus , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de Virulência/genética
14.
J Bacteriol ; 192(14): 3574-83, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20453089

RESUMO

Moraxella catarrhalis is an emerging human-restricted respiratory tract pathogen that is a common cause of childhood otitis media and exacerbations of chronic obstructive pulmonary disease in adults. Here, we report the first completely assembled and annotated genome sequence of an isolate of M. catarrhalis, strain RH4, which originally was isolated from blood of an infected patient. The RH4 genome consists of 1,863,286 nucleotides that form 1,886 protein-encoding genes. Comparison of the RH4 genome to the ATCC 43617 contigs demonstrated that the gene content of both strains is highly conserved. In silico phylogenetic analyses based on both 16S rRNA and multilocus sequence typing revealed that RH4 belongs to the seroresistant lineage. We were able to identify almost the entire repertoire of known M. catarrhalis virulence factors and mapped the members of the biosynthetic pathways for lipooligosaccharide, peptidoglycan, and type IV pili. Reconstruction of the central metabolic pathways suggested that RH4 relies on fatty acid and acetate metabolism, as the genes encoding the enzymes required for the glyoxylate pathway, the tricarboxylic acid cycle, the gluconeogenic pathway, the nonoxidative branch of the pentose phosphate pathway, the beta-oxidation pathway of fatty acids, and acetate metabolism were present. Moreover, pathways important for survival under challenging in vivo conditions, such as the iron-acquisition pathways, nitrogen metabolism, and oxidative stress responses, were identified. Finally, we showed by microarray expression profiling that approximately 88% of the predicted coding sequences are transcribed under in vitro conditions. Overall, these results provide a foundation for future research into the mechanisms of M. catarrhalis pathogenesis and vaccine development.


Assuntos
Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/fisiologia , Genoma Bacteriano , Moraxella catarrhalis/genética , Proteínas de Bactérias , Cromossomos Bacterianos , Metabolismo Energético/fisiologia , Genes Bacterianos , Humanos , Ferro/metabolismo , Dados de Sequência Molecular , Estresse Oxidativo , Transporte Proteico , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
15.
Vaccine ; 38(43): 6741-6750, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32888739

RESUMO

Food poisoning in humans caused by Salmonella enterica remains a significant global public health concern, with the majority of infections associated with the consumption of contaminated eggs or poultry products. The safety and efficacy of a novel inactivated trivalent Salmonella enterica vaccine containing in addition to Salmonella serovars Enteritidis (O:9, serogroup D) and Typhimurium (O:4, serogroup B) also serovar Infantis (O:7, serogroup C1) formulated with an aluminium hydroxide-gel adjuvant was evaluated under field conditions. A total of 10,229 broiler breeder pullets, housed under commercial conditions, were vaccinated at 10 and 17 weeks of age by the intramuscular route in the breast muscle. The vaccine was safe with no local or systemic reactions or adverse effects on bird performance related to the vaccine detected. Vaccination resulted in notable increases in serovar specific antibodies that were maintained until at least 56 weeks of age. Vaccinated birds subjected to homologous challenges around onset of lay showed significantly reduced faecal shedding and organ invasion. Following heterologous challenge with S. Hadar (O:8, serogroup C2) faecal shedding was significantly reduced. These results demonstrate that this novel vaccine could play a significant role in a comprehensive Salmonella control programme intended to reduce both the incidence of food poisoning in humans and the use of antibiotics during poultry production.


Assuntos
Doenças das Aves Domésticas , Salmonelose Animal , Vacinas contra Salmonella , Salmonella enterica , Animais , Galinhas , Feminino , Humanos , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/prevenção & controle , Salmonella enteritidis , Vacinas de Produtos Inativados
16.
BMJ Open ; 9(11): e029422, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31694844

RESUMO

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) is the most common childhood behavioural disorder, causing significant impediment to a child's development. It is a complex disorder with numerous contributing (epi)genetic and environmental factors. Currently, treatment consists of behavioural and pharmacological therapy. However, ADHD medication is associated with several side effects, and concerns about long-term effects and efficacy exist. Therefore, there is considerable interest in the development of alternative treatment options. Double-blind research investigating the effects of a few-foods diet (FFD) has demonstrated a significant decrease in ADHD symptoms following an FFD. However, an FFD requires a considerable effort of both child and parents, limiting its applicability as a general ADHD treatment. To make FFD intervention less challenging or potentially obsolete, we need to understand how, and in which children, an FFD affects ADHD behaviour and, consequently, the child's well-being. We hypothesise that an FFD affects brain function, and that the nutritional impact on ADHD is effectuated by a complex interplay between the microbiota, gut and brain, that is, the microbiota-gut-brain axis. METHODS AND ANALYSIS: The Biomarker Research in ADHD: the Impact of Nutrition (BRAIN) study is an open-label trial with researchers blinded to changes in ADHD symptoms during sample processing and initial data analyses. ETHICS AND DISSEMINATION: The Medical Research and Ethics Committee of Wageningen University has approved this study (NL63851.081.17, application 17/24). Results will be disseminated through peer-reviewed journal publications, conference presentations, (social) media and the BRAIN study website. A summary of the findings will be provided to the participants. TRIAL REGISTRATION NUMBER: NCT03440346. STUDY DATES: Collection of primary outcome data started in March 2018 and will be ongoing until 100 children have participated in the study. Sample data analysis will start after all samples have been collected.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/terapia , Comportamento Infantil , Transtornos da Nutrição Infantil/terapia , Estado Nutricional , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Transtorno do Deficit de Atenção com Hiperatividade/dietoterapia , Criança , Transtornos da Nutrição Infantil/complicações , Transtornos da Nutrição Infantil/dietoterapia , Proteção da Criança/estatística & dados numéricos , Ensaios Clínicos como Assunto , Método Duplo-Cego , Feminino , Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/terapia , Humanos , Masculino
17.
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
18.
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.

19.
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
20.
Mitochondrial DNA B Resour ; 1(1): 447-449, 2016 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-33473515

RESUMO

The Gambian epauletted fruit bat, Epomophorus gambianus, is widely distributed across sub-Saharan Africa. Its assembled and annotated mitochondrial genome (GenBank accession no. KT963027) is 16,702 bases in length, containing 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two non-coding regions: the control region (D-loop) and the origin of light-strand replication (OL). The average base composition is 32.2% A; 27.6% C; 14% G; and 26.1% T. The mitogenome presented a structural composition greatly conserved between members of the Pteropodidae family.

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