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1.
FEMS Microbiol Ecol ; 96(2)2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31873729

RESUMO

Achromatium oxaliferum is a large sulfur bacterium easily recognized by large intracellular calcium carbonate bodies. Although these bodies often fill major parts of the cells' volume, their role and specific intracellular location are unclear. In this study, we used various microscopy and staining techniques to identify the cell compartment harboring the calcium carbonate bodies. We observed that Achromatium cells often lost their calcium carbonate bodies, either naturally or induced by treatments with diluted acids, ethanol, sodium bicarbonate and UV radiation which did not visibly affect the overall shape and motility of the cells (except for UV radiation). The water-soluble fluorescent dye fluorescein easily diffused into empty cavities remaining after calcium carbonate loss. Membranes (stained with Nile Red) formed a network stretching throughout the cell and surrounding empty or filled calcium carbonate cavities. The cytoplasm (stained with FITC and SYBR Green for nucleic acids) appeared highly condensed and showed spots of dissolved Ca2+ (stained with Fura-2). From our observations, we conclude that the calcium carbonate bodies are located in the periplasm, in extra-cytoplasmic pockets of the cytoplasmic membrane and are thus kept separate from the cell's cytoplasm. This periplasmic localization of the carbonate bodies might explain their dynamic formation and release upon environmental changes.


Assuntos
Carbonato de Cálcio/metabolismo , Bactérias Aeróbias Gram-Negativas/metabolismo , Periplasma/metabolismo , Cálcio/metabolismo , Citoplasma/metabolismo , Bactérias Aeróbias Gram-Negativas/citologia , Enxofre/metabolismo
2.
Future Microbiol ; 14: 1235-1242, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31475868

RESUMO

Sarecycline is a novel, narrow-spectrum, once-daily tetracycline-derived oral antibiotic that is FDA-approved in the US to be taken with or without food for moderate-to-severe acne vulgaris for ages 9 years of age and older. Sarecycline possesses anti-inflammatory properties and potent activity against Gram-positive bacteria, including activity against multiple strains of Cutibacterium acnes, while exhibiting minimal activity against enteric aerobic Gram-negative bacteria. Unlike many acne studies, sarecycline was investigated for chest and back acne. Significant reduction in inflammatory lesions was seen at week 12 at 1.5 mg/kg/day of sarecycline, with statistically significant improvement seen as early as week 3. No reports of phototoxicity, dizziness, pseudotumor cerebri or lupus but 1.2% nausea and 1.2% vaginal candidiasis was reported in the pivotal Phase III studies.


Assuntos
Acne Vulgar/tratamento farmacológico , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Tetraciclinas/uso terapêutico , Acne Vulgar/microbiologia , Anti-Inflamatórios/uso terapêutico , Ensaios Clínicos Fase III como Assunto , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Propionibacteriaceae/efeitos dos fármacos
4.
Antonie Van Leeuwenhoek ; 112(2): 263-274, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30194507

RESUMO

We investigated the intracellular dynamics of calcite and sulfur in the large sulfur-oxidizing, calcite-accumulating bacterium Achromatium, with an emphasis on oxygen exposure as a physiological control. For this purpose, morphological changes and possible accretion mechanisms of calcite granules in cells that were freshly collected from natural Achromatium-containing sediment were compared to cells from the same source after prolonged exposure to atmospheric oxygen. Intracellular sulfur is oxidized and removed in response to oxygen exposure. Calcite granules also undergo distinct oxygen-related dynamics; they alternate between tightly packaged, smooth granules with narrow but sharply defined interstitial spaces in atmospheric oxygen-exposed cells, and more loosely packaged granules with irregular, bumpy surface texture and larger interstitial spaces in cells that were not artificially exposed to oxygen. These results suggest that morphological changes of the calcite granules reflect their changing physiological role inside the cell. Sulfur oxidation and calcite dissolution appear to be linked in that proton generation during sulfur oxidation is buffered by gradual calcite erosion, visible in the smooth, rounded surface morphology observed after oxygen exposure. Our results support the hypothesis that calcite dynamics buffer the intracellular pH fluctuations linked to electron acceptor limitation during proton-consuming sulfide oxidation to sulfur, and electron acceptor abundance during proton-generating sulfur oxidation to sulfate.


Assuntos
Carbonato de Cálcio/metabolismo , Bactérias Aeróbias Gram-Negativas/metabolismo , Enxofre/metabolismo , Aerobiose , Oxirredução , Oxigênio/metabolismo
5.
Curr Microbiol ; 75(12): 1584-1588, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30238241

RESUMO

A Gram-negative, yellow-pigmented, aerobic bacterium, designated strain B51-30T, was isolated from oil-well production liquid in Baolige oilfield, China. The strain was able to grow at pH 6-10 (optimum at pH 7.5), in 0-6% (w/v) NaCl (optimum at 1%, w/v) at 15-55 °C (optimum at 45 °C). Cells of the isolate were non-motile and non-spore-forming rods. The major cellular fatty acids were iso-C15:0, iso-C11:0, iso-C11:0 3OH, iso-C17:1 ω9c, and iso-C17:0. Ubiquinone 8 was the predominant respiratory quinone. The major polar lipids consisted of phosphatidylethanolamine and diphosphatidylglycerol. The genomic DNA G+C content of the isolate was 70.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain B51-30T was most closely related to Coralloluteibacterium stylophorae KCTC 52167T (98.7% similarity). The two strains showed DNA-DNA relatedness values of 58.5%. Genotypic and phenotypic features indicate that strain B51-30T represents a novel species of the genus Coralloluteibacterium, for which the name Coralloluteibacterium thermophilus sp. nov. is proposed. The type strain is B51-30T (= CGMCC 1.13574T = KCTC 62780T).


Assuntos
Gammaproteobacteria/isolamento & purificação , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Campos de Petróleo e Gás/microbiologia , Técnicas de Tipagem Bacteriana/métodos , Composição de Bases/genética , China , DNA Bacteriano/genética , Ácidos Graxos/genética , Gammaproteobacteria/genética , Bactérias Aeróbias Gram-Negativas/genética , Fosfolipídeos/genética , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA/métodos , Microbiologia do Solo
6.
Curr Opin Crit Care ; 24(5): 332-338, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30036192

RESUMO

PURPOSE OF REVIEW: Successful treatment of patients with hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) remains a difficult and complex undertaking. Better knowledge of the pathogens involved in that setting may allow reassessment of our current modalities of therapy and definition of better protocols. RECENT FINDINGS: Microorganisms responsible for HAP/VAP differ according to geographic areas, ICU patients' specific characteristics, durations of hospital and ICU stays before onset of the disease, and risk factors for MDR pathogens. However, a number of studies have shown that Gram-negative bacilli (GNB) - particularly Pseudomonas aeruginosa and Enterobacteriaceae - cause many of the respiratory infections in this setting, with minimal differences between HAP and VAP, indicating that the cause depends more on the underlying clinical condition of patients rather than previous intubation. SUMMARY: When selecting initial antimicrobial therapy in patients with HAP/VAP, more attention should be paid to individual risk factors for MDR pathogens, severity of the clinical situation, and the local epidemiology than to the type of pneumonia.


Assuntos
Antibacterianos/uso terapêutico , Bactérias Aeróbias Gram-Negativas/patogenicidade , Pneumonia Associada a Assistência à Saúde/tratamento farmacológico , Pneumonia Associada a Assistência à Saúde/microbiologia , Unidades de Terapia Intensiva , Pneumonia Associada à Ventilação Mecânica/tratamento farmacológico , Pneumonia Associada à Ventilação Mecânica/microbiologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Pneumonia Associada a Assistência à Saúde/epidemiologia , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Pneumonia Associada à Ventilação Mecânica/epidemiologia , Medição de Risco
7.
Eur Respir Rev ; 27(148)2018 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-29950304

RESUMO

Haemophilus influenzae, Moraxella catarrhalis and Pseudomonas aeruginosa are common Gram-negative pathogens associated with an array of pulmonary diseases. All three species have multiple adhesins in their outer membrane, i.e. surface structures that confer the ability to bind to surrounding cells, proteins or tissues. This mini-review focuses on proteins with high affinity for the components of the extracellular matrix such as collagen, laminin, fibronectin and vitronectin. Adhesins are not structurally related and may be lipoproteins, transmembrane porins or large protruding trimeric auto-transporters. They enable bacteria to avoid being cleared together with mucus by attaching to patches of exposed extracellular matrix, or indirectly adhering to epithelial cells using matrix proteins as bridging molecules. As more adhesins are being unravelled, it is apparent that bacterial adhesion is a highly conserved mechanism, and that most adhesins target the same regions on the proteins of the extracellular matrix. The surface exposed adhesins are prime targets for new vaccines and the interactions between proteins are often possible to inhibit with interfering molecules, e.g heparin. In conclusion, this highly interesting research field of microbiology has unravelled host-pathogen interactions with high therapeutic potential.


Assuntos
Adesinas Bacterianas/imunologia , Aderência Bacteriana , Proteínas da Matriz Extracelular/imunologia , Bactérias Aeróbias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Evasão da Resposta Imune , Pulmão/imunologia , Infecções Respiratórias/imunologia , Adesinas Bacterianas/metabolismo , Animais , Proteínas da Matriz Extracelular/metabolismo , Bactérias Aeróbias Gram-Negativas/metabolismo , Bactérias Aeróbias Gram-Negativas/patogenicidade , Infecções por Bactérias Gram-Negativas/metabolismo , Infecções por Bactérias Gram-Negativas/microbiologia , Haemophilus influenzae/imunologia , Haemophilus influenzae/metabolismo , Haemophilus influenzae/patogenicidade , Interações Hospedeiro-Patógeno , Humanos , Pulmão/metabolismo , Pulmão/microbiologia , Moraxella catarrhalis/imunologia , Moraxella catarrhalis/metabolismo , Moraxella catarrhalis/patogenicidade , Pseudomonas aeruginosa/imunologia , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Infecções Respiratórias/metabolismo , Infecções Respiratórias/microbiologia
8.
Antonie Van Leeuwenhoek ; 111(10): 1845-1853, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29603043

RESUMO

A Gram-stain negative, aerobic, rod-shaped, non-motile, yellow-pigmented and non-spore-forming bacterial strain, designated PM5-8T, was isolated from a culture of a marine toxigenic dinoflagellate Prorocentrum mexicanum PM01. Strain PM5-8T grew at 15-35 °C (optimum, 25-30 °C) and pH 6-11 (optimum, 7.5-8). Cells required at least 1.5% (w/v) NaCl for growth, and can tolerate up to 7.0% with the optimum of 4%. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strain PM5-8T is closely related to members of the genus Hoeflea, with high sequence similarities with Hoeflea halophila JG120-1T (97.06%) and Hoeflea alexandrii AM1V30T (97.01%). DNA-DNA hybridization values between the isolate and other type strains of recognized species of the genus Hoeflea were between 11.8 and 25.2%, which is far below the value of 70% threshold for species delineation. The DNA G + C content was 50.3 mol%. The predominant cellular fatty acids of the strain were identified as summed feature 8 (C16:1 ω7c and/or C16:1 ω6c; 51.5%), C18:1 ω7c 11-methyl (20.7%), C16:0 (17.2%) and C18:0 (5.7%). The major respiratory quinone was Q-10. Polar lipids profiles contained phosphatidylcholine, phosphatidylglycerol, sulfoquinovosyl diacylglycerol, phosphatidylmono- methylethanolamine, phosphatidylethanolamine and four unidentified lipids. On the basis of the polyphasic taxonomic data presented, strain PM5-8T (= CCTCC AB 2016294T = KCTC 62490T) represents a novel species of the genus Hoeflea, for which the name Hoeflea prorocentri sp. nov. is proposed.


Assuntos
Organismos Aquáticos/microbiologia , Dinoflagelados/microbiologia , Bactérias Aeróbias Gram-Negativas/classificação , DNA Bacteriano , Bactérias Aeróbias Gram-Negativas/química , Bactérias Aeróbias Gram-Negativas/genética , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Metabolômica/métodos , Tipagem Molecular , Fenótipo , Filogenia , RNA Ribossômico 16S/genética
9.
Microb Ecol ; 76(3): 584-587, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29492594

RESUMO

Achromatium is the largest freshwater bacterium known to date and easily recognised by conspicuous calcite bodies filling the cell volume. Members of this genus are highly abundant in diverse aquatic sediments and may account for up to 90% of the bacterial biovolume in the oxic-anoxic interfaces. The high abundance implies that Achromatium is either rapidly growing or hardly prone to predation. As Achromatium is still uncultivated and does not appear to grow fast, one could assume that the cells might escape predation by their unusual shape and composition. However, we observed various members of the meiofauna grazing or parasitizing on Achromatium. By microphotography, we documented amoebae, ciliates, oligochetes and plathelminthes having Achromatium cells ingested. Some Achromatium cells harboured structures resembling sporangia of parasitic fungi (chytrids) that could be stained with the chitin-specific dye Calcofluor White. Many Achromatia carried prokaryotic epibionts in the slime layer surrounding the cells. Their regular distribution over the cell might indicate that they are commensalistic rather than harming their hosts. In conclusion, we report on various interactions of Achromatium with the sediment community and show that although Achromatium cells are a crispy diet, full of calcite bodies, predators do not spare them.


Assuntos
Sedimentos Geológicos/microbiologia , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Lagos/microbiologia , Amoeba/fisiologia , Animais , Cilióforos/fisiologia , Sedimentos Geológicos/parasitologia , Bactérias Aeróbias Gram-Negativas/classificação , Bactérias Aeróbias Gram-Negativas/genética , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Lagos/parasitologia , Oligoquetos/fisiologia
10.
J Appl Microbiol ; 124(2): 408-422, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29178633

RESUMO

AIMS: To enhance the antimicrobial and antibiofilm activity of norfloxacin against the planktonic and biofilm mode of growth in ESKAPE pathogens using chemically modified norfloxacin salts. METHODS AND RESULTS: Antimicrobial testing, synergy testing and time-kill curve analysis were performed to evaluate antibacterial effect of norfloxacin carboxylic acid salts against ESKAPE pathogens. In vivo efficacy to reduce bacterial bioburden was evaluated in zebrafish infection model. Crystal violet assay and live-dead staining were performed to discern antibiofilm effect. Membrane permeability, integrity and molecular docking studies were carried out to ascertain the mechanism of action. The carboxylic acid salts, relative to parent molecule norfloxacin, displayed two- to fourfold reduction in minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to displaying potent bacteriostatic effect against certain members of ESKAPE pathogens. In vivo treatments revealed that norfloxacin tartrate (SRIN2) reduced MRSA bioburden by greater than 1 log fold relative to parent molecule in the muscle tissue. In silico docking with gyrA of S. aureus showed increased affinity of SRIN2 towards DNA gyrase. The enhanced antibacterial effect of norfloxacin salts could be partially accounted by altered membrane permeability in S. aureus and perturbed membrane integrity in P. aeruginosa. Antibiofilm studies revealed that SRIN2 (norfloxacin tartrate) and SRIN3 (norfloxacin benzoate) exerted potent antibiofilm effect particularly against Gram-negative ESKAPE pathogens. The impaired colonization of both S. aureus and P. aeruginosa due to improved norfloxacin salts was further supported by live-dead imaging. CONCLUSION: Norfloxacin carboxylic acid salts can act as potential alternatives in terms of drug resensitization and reuse. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study shows that carboxylic acid salts of norfloxacin could be effectively employed to treat both planktonic- and biofilm-based infections caused by select members of ESKAPE pathogens.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/microbiologia , Norfloxacino/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Acinetobacter baumannii/fisiologia , Animais , Antibacterianos/química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/farmacologia , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Enterobacter/fisiologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Bactérias Aeróbias Gram-Negativas/fisiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Klebsiella pneumoniae/fisiologia , Testes de Sensibilidade Microbiana , Norfloxacino/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/fisiologia
11.
Biochemistry (Mosc) ; 82(11): 1295-1303, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29223156

RESUMO

In the aerobic methanotrophic bacteria Methylomicrobium alcaliphilum 20Z, Methylococcus capsulatus Bath, and Methylosinus trichosporium OB3b, the biochemical properties of hydroxypyruvate reductase (Hpr), an indicator enzyme of the serine pathway for assimilation of reduced C1-compounds, were comparatively analyzed. The recombinant Hpr obtained by cloning and heterologous expression of the hpr gene in Escherichia coli catalyzed NAD(P)H-dependent reduction of hydroxypyruvate or glyoxylate, but did not catalyze the reverse reactions of D-glycerate or glycolate oxidation. The absence of the glycerate dehydrogenase activity in the methanotrophic Hpr confirmed a key role of the enzyme in utilization of C1-compounds via the serine cycle. The enzyme from Ms. trichosporium OB3b realizing the serine cycle as a sole assimilation pathway had much higher special activity and affinity in comparison to Hpr from Mm. alcaliphilum 20Z and Mc. capsulatus Bath assimilating carbon predominantly via the ribulose monophosphate (RuMP) cycle. The hpr gene was found as part of gene clusters coding the serine cycle enzymes in all sequenced methanotrophic genomes except the representatives of the Verrucomicrobia phylum. Phylogenetic analyses revealed two types of Hpr: (i) Hpr of methanotrophs belonging to the Gammaproteobacteria class, which use the serine cycle along with the RuMP cycle, as well as of non-methylotrophic bacteria belonging to the Alphaproteobacteria class; (ii) Hpr of methylotrophs from Alpha- and Betaproteobacteria classes that use only the serine cycle and of non-methylotrophic representatives of Betaproteobacteria. The putative role and origin of hydroxypyruvate reductase in methanotrophs are discussed.


Assuntos
Hidroxipiruvato Redutase/classificação , Methylococcaceae/enzimologia , Methylosinus/enzimologia , Filogenia , Alphaproteobacteria , Gammaproteobacteria , Bactérias Aeróbias Gram-Negativas/classificação , Bactérias Aeróbias Gram-Negativas/enzimologia , Hidroxipiruvato Redutase/metabolismo , Methylobacillus , Methylobacteriaceae , Methylophilaceae , Serina/metabolismo
12.
Nat Commun ; 8(1): 455, 2017 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-28878209

RESUMO

Polyploid bacteria are common, but the genetic and functional diversity resulting from polyploidy is unknown. Here we use single-cell genomics, metagenomics, single-cell amplicon sequencing, and fluorescence in situ hybridization, to show that individual cells of Achromatium oxaliferum, the world's biggest known freshwater bacterium, harbor genetic diversity typical of whole bacterial communities. The cells contain tens of transposable elements, which likely cause the unprecedented diversity that we observe in the sequence and synteny of genes. Given the high within-cell diversity of the usually conserved 16S ribosomal RNA gene, we suggest that gene conversion occurs in multiple, separated genomic hotspots. The ribosomal RNA distribution inside the cells hints to spatially differential gene expression. We also suggest that intracellular gene transfer may lead to extensive gene reshuffling and increased diversity.The cells of Achromatium bacteria are remarkably large and contain multiple chromosome copies. Here, Ionescu et al. show that chromosome copies within individual cells display high diversity, similar to that of bacterial communities, and contain tens of transposable elements.


Assuntos
Genoma Bacteriano , Bactérias Aeróbias Gram-Negativas/citologia , Bactérias Aeróbias Gram-Negativas/genética , Enxofre/metabolismo , Evolução Biológica , Cromossomos Bacterianos/genética , Regulação Bacteriana da Expressão Gênica , Técnicas de Transferência de Genes , Variação Genética , Bactérias Aeróbias Gram-Negativas/ultraestrutura , Hibridização in Situ Fluorescente , Funções Verossimilhança , Metagenômica , Modelos Genéticos , Óperon/genética , Poliploidia , RNA Ribossômico 16S/genética , Sintenia/genética
13.
Biochem J ; 474(16): 2779-2784, 2017 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-28784697

RESUMO

Many secreted bacterial effector proteins play a critical role in host-pathogen interactions by mediating a variety of post-translational modifications, some of which do not occur natively within the eukaryotic proteome. The characterization of bacterial effector protein activity remains an important step to understanding the subversion of host cell biology during pathogen infection and although molecular biology and immunochemistry remain critical tools for gaining insights into bacterial effector functions, increasingly mass spectrometry (MS) and proteomic approaches are also playing an indispensable role. The focus of this editorial is to highlight the strengths of specific MS approaches and their utility for the characterization of bacterial effector activity. With the capability of new generation MS instrumentation, MS-based technologies can provide information that is inaccessible using traditional molecular or immunochemical approaches.


Assuntos
Pesquisa Biomédica/métodos , Espectrometria de Massas/métodos , Proteômica/métodos , Efetores Semelhantes a Ativadores de Transcrição/química , Animais , Pesquisa Biomédica/tendências , Bactérias Aeróbias Gram-Negativas/patogenicidade , Bactérias Aeróbias Gram-Negativas/fisiologia , Bactérias Gram-Positivas/patogenicidade , Bactérias Gram-Positivas/fisiologia , Interações Hospedeiro-Patógeno , Humanos , Espectrometria de Massas/tendências , Estrutura Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/fisiologia , Papel Profissional , Processamento de Proteína Pós-Traducional , Proteômica/tendências , Pesquisadores , Efetores Semelhantes a Ativadores de Transcrição/metabolismo , Efetores Semelhantes a Ativadores de Transcrição/fisiologia , Recursos Humanos
14.
Hematol Oncol Stem Cell Ther ; 10(4): 228-232, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28692817

RESUMO

Bacterial infections remain a common complication of hematopoietic stem cell transplantation (HSCT), especially in the pre-engraftment phase. The risk of bacterial infections is mainly related to neutropenia, mucositis, and the presence of vascular lines. Most parts of the world have witnessed a shift in epidemiology toward Gram-negative bacteria; a large proportion of which are resistant to fluoroquinolones, extended-spectrum beta-lactams, carbapenems, and in some units even colistin. Meticulous infection control practices are essential for prevention of bacterial infections in HSCT. The role of routine prophylactic antibiotics is limited in settings with high rates of bacterial resistance. If used, prophylactic antibiotics should be limited to high-risk patients, and the agents are selected based on local resistance profiles. Neutropenic fever is a medical emergency in most HSCT recipients. Prompt clinical evaluation is paramount, along with the intravenous administration of appropriate empiric antimicrobials, typically an antipseudomonal beta-lactam agent. Glycopeptides should only be considered if the patient is hemodynamically unstable or Gram-positive infection is suspected. Additional Gram-negative agents, such as colistin or aminoglycosides, may be added if extensive Gram-negative resistance is expected. To mitigate increasing bacterial resistance, empiric antibiotic regimens should be rationalized or discontinued as soon as possible.


Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana , Bactérias Aeróbias Gram-Negativas , Infecções por Bactérias Gram-Negativas , Transplante de Células-Tronco Hematopoéticas , Infecções por Bactérias Gram-Negativas/etiologia , Infecções por Bactérias Gram-Negativas/prevenção & controle , Humanos
15.
Nutrients ; 9(4)2017 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-28368356

RESUMO

Green cincau (Premna oblongifolia Merr) is an Indonesian food plant with a high dietary fibre content. Research has shown that dietary fibre mixtures may be more beneficial for colorectal cancer prevention than a single dietary fibre type. The aim of this study was to investigate the effects of green cincau extract on short chain fatty acid (SCFA) production in anaerobic batch cultures inoculated with human faecal slurries and to compare these to results obtained using different dietary fibre types (pectin, inulin, and cellulose), singly and in combination. Furthermore, fermentation supernatants (FSs) were evaluated in Caco-2 cells for their effect on cell viability, differentiation, and apoptosis. Cincau increased total SCFA concentration by increasing acetate and propionate, but not butyrate concentration. FSs from all dietary fibre sources, including cincau, reduced Caco-2 cell viability. However, the effects of all FSs on cell viability, cell differentiation, and apoptosis were not simply explainable by their butyrate content. In conclusion, products of fermentation of cincau extracts induced cell death, but further work is required to understand the mechanism of action. This study demonstrates for the first time that this Indonesian traditional source of dietary fibre may be protective against colorectal cancer.


Assuntos
Anticarcinógenos/metabolismo , Apoptose , Neoplasias do Colo/prevenção & controle , Fibras na Dieta/metabolismo , Microbioma Gastrointestinal , Extratos Vegetais/metabolismo , Prebióticos , Anticarcinógenos/isolamento & purificação , Células CACO-2 , Diferenciação Celular , Sobrevivência Celular , Celulose/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/microbiologia , Neoplasias do Colo/patologia , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Fermentação , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Bactérias Aeróbias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/isolamento & purificação , Bactérias Gram-Positivas/metabolismo , Humanos , Indonésia , Inulina/metabolismo , Lamiaceae/química , Pectinas/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Prebióticos/análise
16.
Artigo em Inglês | MEDLINE | ID: mdl-28348155

RESUMO

The correlation of the clinical efficacy of ceftazidime-avibactam (plus metronidazole) with that of meropenem was evaluated in subjects infected with Gram-negative isolates having characterized ß-lactam resistance mechanisms from the complicated intra-abdominal infection (cIAI) phase 3 clinical trials. Enterobacteriaceae isolates displaying ceftriaxone and/or ceftazidime MIC values of ≥2 µg/ml and Pseudomonas aeruginosa isolates with ceftazidime MIC values of ≥16 µg/ml were characterized for extended-spectrum-ß-lactamase (ESBL) content. Enterobacteriaceae and P. aeruginosa isolates with imipenem and meropenem MIC values of ≥2 and ≥8 µg/ml, respectively, were tested for carbapenemase genes. The primary efficacy endpoint was clinical cure at test of cure (TOC) among the members of the microbiologically modified intention-to-treat (mMITT) population. A total of 14.5% (56/387) and 18.8% (74/394) of patients in the ceftazidime-avibactam and meropenem arms had isolates that met the MIC screening criteria at the baseline visit, respectively. CTX-M variants alone (29.7%; 41/138) or in combination with OXA-1/30 (35.5%; 49/138), most commonly, blaCTX-M group 1 variants (79/90; 87.8%), represented the ß-lactamases most frequently observed among Enterobacteriaceae isolates. Among the patients infected with pathogens that did not meet the screening criteria, 82.2% showed clinical cure in the ceftazidime-avibactam group versus 85.9% in the meropenem group. Among patients infected with any pathogens that met the MIC screening criteria, clinical cure rates at TOC were 87.5% and 86.5% for the ceftazidime-avibactam and meropenem groups, respectively. Ceftazidime-avibactam had clinical cure rates of 92.5% to 90.5% among patients infected with ESBL- and/or carbapenemase-producing Enterobacteriaceae strains at the baseline visit, while meropenem showed rates of 84.9% to 85.4%. The ceftazidime-avibactam and meropenem groups had cure rates of 75.0% and 86.7%, respectively, among patients having any pathogens producing AmpC enzymes. The efficacy of ceftazidime-avibactam was similar to that of meropenem for treatment of cIAI caused by ESBL-producing organisms. (This study has been registered at ClinicalTrials.gov under registration no. NCT01499290 and NCT01500239.).


Assuntos
Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Bactérias Aeróbias Gram-Negativas/patogenicidade , Infecções Intra-Abdominais/tratamento farmacológico , beta-Lactamases/farmacologia , beta-Lactamases/uso terapêutico , Compostos Azabicíclicos , Ceftazidima , Combinação de Medicamentos , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Humanos , Infecções Intra-Abdominais/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Testes de Sensibilidade Microbiana
17.
Curr Microbiol ; 74(3): 404-412, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28184991

RESUMO

Two closely related aerobic, Gram reaction-negative rod-shaped bacteria (S7-75T and S7-80) were isolated from mucus of coral Fungia seychellensis from Andaman Sea, India. Heterotrophic growth on marine agar was observed at 4-35 °C and pH 6.5-10.5; optimum growth occurred at 25-30 °C and pH 7-8. 16 S rRNA sequence analysis confirmed the strains belonged to the genus Sulfitobacter and the two isolates shared more than 99.28% pairwise sequence similarity. DNA-DNA similarity between two isolates S7-75T and S7-80 was above 96%. Strain S7-75T showed maximum 16S rRNA similarity of 99.64% with Sulfitobacter pontiacus LMG 19752T. However, DNA-DNA relatedness between strain S7-75T and S. pontiacus LMG 19752T confirmed the placement of strain S7-75T as subspecies under the species S. pontiacus. Further, pulsed-field gel electrophoresis (PFGE), REP-PCR, ERIC-PCR fingerprint patterns and lipid profiles also differentiated strain S7-75T from the reference strain of S. pontiacus LMG 19752T. The DNA G+C content was 59.8 mol%. Q10 was the major respiratory quinone. Based on polyphasic analysis, the isolate S7-75T represents a subspecies of S. pontiacus for which the name S. pontiacus subsp. fungiae subsp. nov. is proposed with S7-75T (=JCM 31094T = LMG 29158T) as type strain.


Assuntos
Antozoários/microbiologia , Bactérias Aeróbias Gram-Negativas/genética , Animais , Composição de Bases/genética , DNA Bacteriano/genética , DNA Ribossômico/genética , Bactérias Aeróbias Gram-Negativas/classificação , Rhodobacteraceae/classificação , Rhodobacteraceae/genética
18.
Appl Environ Microbiol ; 83(7)2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28130300

RESUMO

On the basis of bioinformatic evidence, we suspected that proteins with a CYTH (CyaB thiamine triphosphatase) domain and/or a CHAD (conserved histidine α-helical domain) motif might represent polyphosphate (polyP) granule-associated proteins. We found no evidence of polyP targeting by proteins with CYTH domains. In contrast, two CHAD motif-containing proteins from Ralstonia eutropha H16 (A0104 and B1017) that were expressed as fusions with enhanced yellow fluorescent protein (eYFP) colocalized with polyP granules. While the expression of B1017 was not detectable, the A0104 protein was specifically identified in an isolated polyP granule fraction by proteome analysis. Moreover, eYFP fusions with the CHAD motif-containing proteins MGMSRV2-1987 from Magnetospirillum gryphiswaldense and PP2307 from Pseudomonas putida also colocalized with polyP granules in a transspecies-specific manner. These data indicated that CHAD-containing proteins are generally attached to polyP granules. Together with the findings from four previously polyP-attached proteins (polyP kinases), the results of this study raised the number of polyP-associated proteins in R. eutropha to six. We suggest designating polyP granule-bound proteins with CHAD motifs as phosins (phosphate), analogous to phasins and oleosins that are specifically bound to the surface of polyhydroxyalkanoate (PHA) granules in PHA-accumulating bacteria and to oil droplets in oil seed plants, respectively.IMPORTANCE The importance of polyphosphate (polyP) for life is evident from the ubiquitous presence of polyP in all species on earth. In unicellular eukaryotic microorganisms, polyP is located in specific membrane-enclosed organelles, called acidocalcisomes. However, in most prokaryotes, polyP is present as insoluble granules that have been designated previously as volutin granules. Almost nothing is known regarding the macromolecular composition of polyP granules. Particularly, the absence or presence of cellular compounds on the surface of polyP granules has not yet been investigated. In this study, we identified a novel class of proteins that are attached to the surface of polyP granules in three model species of Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria These proteins are characterized by the presence of a CHAD (conserved histidine α-helical domain) motif that functions as a polyP granule-targeting signal. We suggest designating CHAD motif-containing proteins as phosins [analogous to phasins for poly(3-hydroxybutyrate)-associated proteins and to oleosins for oil droplet-associated proteins in oil seed plants]. The expression of phosins in different species confirmed their polyP-targeting function in a transspecies-specific manner. We postulate that polyP granules in prokaryotic species generally have a complex surface structure that consists of one to several polyP kinases and phosin proteins. We suggest differentiating polyP granules from acidocalcisomes by designating them as polyphosphatosomes.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Bactérias Aeróbias Gram-Negativas/metabolismo , Histidina/química , Polifosfatos/química , Proteínas de Bactérias/genética , Biopolímeros , Cupriavidus necator/genética , Cupriavidus necator/metabolismo , Histidina/metabolismo , Proteínas Luminescentes/genética , Magnetospirillum/metabolismo , Polifosfatos/metabolismo , Conformação Proteica em alfa-Hélice , Proteoma , Pseudomonas putida/metabolismo
19.
Res Microbiol ; 168(2): 122-129, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27677682

RESUMO

Advantages of MALDI-TOF MS (MS) were evaluated for diagnosis of bone and joint infections after enrichment of synovial fluid (SF) or crushed osteoarticular samples (CSs). MS was performed after enrichment of SF or crushed osteoarticular samples CS (n = 108) in both aerobic and anaerobic vials. Extraction was performed on 113 vials (SF: n = 47; CS: n = 66), using the Sepsityper® kit prior identification by MS. The performances of MS, score and reproducibility results on bacterial colonies from blood agar and on pellets after enrichment in vials, were compared. MS analysis of the vial resulted in correct identification of bacteria at a species and genus level (80.5% and 92% of cases, respectively). The reproducibility was superior for aerobic Gram-positive bacteria (Staphylococci and Gram-positive bacilli: 100% colonies), as compared to aerobic Gram-negative bacilli (89.7%), anaerobes (83.3%) and Streptococcus/Enterococcus (58.8%). MS performance was significantly better for staphylococci than for streptococci on all identification parameters. For polymicrobial cultures, identification (score>1.5) of two species by MS was acceptable in 92.8% of cases. Use of MS on enrichment pellets of bone samples is an accurate, rapid and robust method for bacterial identification of clinical isolates from osteoarticular infections, except for streptococci, whose identification to species level remains difficult.


Assuntos
Infecções Bacterianas/diagnóstico , Doenças Ósseas Infecciosas/diagnóstico , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Artropatias/diagnóstico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Líquido Sinovial/microbiologia , Infecções Bacterianas/microbiologia , Técnicas Bacteriológicas , Doenças Ósseas Infecciosas/microbiologia , Osso e Ossos/microbiologia , Osso e Ossos/fisiopatologia , Coinfecção/diagnóstico , Coinfecção/microbiologia , Meios de Cultura/química , Bactérias Aeróbias Gram-Negativas/classificação , Bactérias Anaeróbias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/microbiologia , Bactérias Gram-Positivas/classificação , Infecções por Bactérias Gram-Positivas/diagnóstico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Artropatias/microbiologia , Articulações/microbiologia , Articulações/fisiopatologia , Reprodutibilidade dos Testes , Staphylococcus/isolamento & purificação , Streptococcus/isolamento & purificação
20.
J Sci Food Agric ; 97(3): 929-938, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27220662

RESUMO

BACKGROUND: The objective of the present work was to develop strategies for increasing the shelf-life of red raspberries (Rubus idaeus L.), by preventing microorganism growth. RESULTS: Fruits coated with alginate plus lemon essential oil (0.2%) or orange essential oil (0.1%) after 15 days of storage had less red skin than the remaining samples. The less red color verified in these samples was also coincident with the lower concentration of anthocyanins at the end of the experiment as well as the lower capacity for scavenging ABTS free radicals or quenching singlet oxygen. Cyanidin and pelargonidin glucosides were found in raspberries fruits. The edible coatings supplemented with the essential oil of orange either at 0.1% or 0.2% were very efficient for controlling yeast and mold growth after 15 days of storage. To control the development of aerobic mesophilic bacteria the use of essential oil of lemon 0.2% and essential oil of orange 0.1% were the most efficient. CONCLUSION: The application of the film improved post-harvest quality of raspberry, since the addition of essential oils of citrus films promoted to the inhibitory effect of fungi and bacteria growth after 15 days of storage, without changing quality parameters. © 2016 Society of Chemical Industry.


Assuntos
Citrus/química , Conservantes de Alimentos/química , Qualidade dos Alimentos , Armazenamento de Alimentos , Frutas/química , Óleos Voláteis/química , Rubus/química , Alginatos/química , Antocianinas/análise , Antocianinas/química , Antibacterianos/efeitos adversos , Antibacterianos/química , Antibacterianos/metabolismo , Brasil , Conservantes de Alimentos/efeitos adversos , Conservantes de Alimentos/metabolismo , Depuradores de Radicais Livres/análise , Depuradores de Radicais Livres/química , Frutas/microbiologia , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificação , Fungicidas Industriais/efeitos adversos , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Ácido Glucurônico/química , Bactérias Aeróbias Gram-Negativas/crescimento & desenvolvimento , Bactérias Aeróbias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/isolamento & purificação , Ácidos Hexurônicos/química , Humanos , Valor Nutritivo , Óleos Voláteis/efeitos adversos , Óleos Voláteis/metabolismo , Pigmentos Biológicos/análise , Pigmentos Biológicos/química , Análise de Componente Principal , Rubus/microbiologia , Propriedades de Superfície , Leveduras/crescimento & desenvolvimento , Leveduras/isolamento & purificação
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