Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
1.
EMBO Rep ; 22(11): e54000, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34734669

RESUMO

Open Science calls for transparent science and involvement of various stakeholders. Here are examples of and advice for meaningful stakeholder engagement.


Assuntos
Participação dos Interessados
2.
Opt Lett ; 47(17): 4299-4302, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36048638

RESUMO

A closed-loop servo control based on balancing the gain of two probing frequencies is proposed for real-time Brillouin optical time-domain analysis (BOTDA) without post-processing. With the most basic BOTDA hardware setup, the system can perform measurement in 150 ms and track a sudden Brillouin frequency shift (BFS) change in excess of 300 MHz (corresponding to a temperature change of more than 250°C) over ∼5 km of fiber with a spatial resolution of 2 m. Moreover, the feedback loop is independent of the loss experienced by the probe and pump, with no requirement on the BFS uniformity along the fiber. All these advantages make the proposed system suitable for field applications in harsh environments.

3.
FASEB J ; 33(11): 12146-12163, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31370706

RESUMO

The formation of biofilms provides structural and adaptive bacterial response to the environment. In Bacillus species, the biofilm extracellular matrix is composed of exopolysaccharides, hydrophobins, and several functional amyloid proteins. We report, using multiscale approaches such as solid-state NMR (SSNMR), electron microscopy, X-ray diffraction, dynamic light scattering, attenuated total reflection Fourier transform infrared (FTIR), and immune-gold labeling, the molecular architecture of B. subtilis and pathogenic B. cereus functional amyloids. SSNMR data reveal that the major amyloid component TasA in its fibrillar amyloid form contain ß-sheet and α-helical secondary structure, suggesting a nontypical amyloid architecture in B. subtilis. Proteinase K digestion experiments indicate the amyloid moiety is ∼100 aa long, and subsequent SSNMR and FTIR signatures for B. subtilis and B. cereus TasA filaments highlight a conserved amyloid fold, albeit with substantial differences in structural polymorphism and secondary structure composition. Structural analysis and coassembly data on the accessory protein TapA in B. subtilis and its counterpart camelysin in B. cereus reveal a catalyzing effect between the functional amyloid proteins and a common structural architecture, suggesting a coassembly in the context of biofilm formation. Our findings highlight nontypical amyloid behavior of these bacterial functional amyloids, underlining structural variations between biofilms even in closely related bacterial species.-El Mammeri, N., Hierrezuelo, J., Tolchard, J., Cámara-Almirón, J., Caro-Astorga, J., Álvarez-Mena, A., Dutour, A., Berbon, M., Shenoy, J., Morvan, E., Grélard, A., Kauffmann, B., Lecomte, S., de Vicente, A., Habenstein, B., Romero, D., Loquet, A. Molecular architecture of bacterial amyloids in Bacillus biofilms.


Assuntos
Proteínas Amiloidogênicas/química , Bacillus/fisiologia , Proteínas de Bactérias/química , Biofilmes , Espectroscopia de Ressonância Magnética , Metaloproteases/química , Dobramento de Proteína , Estrutura Secundária de Proteína , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Anaerobe ; 55: 124-129, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30550807

RESUMO

Clostridioides difficile is the leading cause of nosocomial diarrhea and antibiotics associated diarrhea, but it is also an increasingly common cause of community diarrhea. In recent years we have observed a progressive increase in the incidence of C. difficile infection (CDI) both at the hospital and community setting that could be explained by the dynamic epidemiology of C. difficile. The present study analyzes changes in the epidemiology of CDI for two years comparing healthcare facility-associated (HCFA) and community-associated (CA) CDI epidemiology, observed in a single laboratory setting. All new episodes of CDI diagnosed during the years 2015-2016 were included in the study and classified as HFCA-, CA- or indeterminate CDI. Isolates were characterized by ribotyping and antimicrobial susceptibility was also determined. A total of 272 primary episodes of different patients were included in the study and classified 55.5% as CA-, 32% as HO-HCFA, 6.25% as CO-HCFA and 6.25% as indeterminate CDI. Overall, ribotype 106 was the most prevalent and also, many patients who suffered recurrent episodes were associated with this ribotype (29%). In fact, ribotype 106 showed a significantly higher recurrence rate than other ribotypes (26% vs 11%, p = 0.03). Moreover, 46% of the moxifloxacin resistant isolates were ribotype 106. No significant differences of antimicrobial resistance were observed between HCFA- and CA-CDI isolates, although fluoroquinolone resistance rates were slightly higher in HCFA-CDI isolates (25% vs 18.5%), and fluoroquinolone resistant ribotypes 106 and 126 were more frequently associated to CA-CDI and ribotype 078 to HCFA-CDI. The increasing incidence of CDI in our health care area is partially explained by the growing prevalence of the epidemic ribotype 106, both in HFCA- and CA-CDI, probably favored by the higher resistance and recurrence rate associated to ribotype 106 isolates.


Assuntos
Clostridioides difficile/classificação , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecções Comunitárias Adquiridas/epidemiologia , Infecção Hospitalar/epidemiologia , Epidemias , Ribotipagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Clostridioides difficile/genética , Feminino , Instalações de Saúde , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Recidiva , Adulto Jovem
5.
Rev Panam Salud Publica ; 41: e51, 2017 Jun 08.
Artigo em Espanhol | MEDLINE | ID: mdl-28614471

RESUMO

OBJECTIVE: Analyze the proposal by the Ministry of Public Health to reform the public financing model in Ecuador with regard to pooling of funds and payment mechanisms. METHOD: A literature review was done of the financing model, the current legal framework, and the budgetary bases in Pubmed, SciELO, LILACS Ecuador, and regional LILACS using the key words health financing, health financing systems, capitation, pooling of funds, health system reform Ecuador, health system Ecuador, and health payment mechanisms. Books and other documents suggested by health systems experts were also included. RESULTS: Review of the financing model enabled identifying the historical segmentation of Ecuador's health system; out of this, the Ministry of Public Health conceived its proposal to reform the financing model. The Ministry's proposed solutions are pooling of funds and payment of services at the first level of care through payment per capita adjusted for socioeconomic and demographic risks. Progress made in reforming the financing model includes design of the proposals and their implementation mechanisms, and discussions with stakeholders. CONCLUSIONS: Implementation of these changes may produce improvements for the health system in efficiency, spreading of risks, incentives for meeting health objectives, as well as contribute to its sustainability and advance toward universal health coverage. Nevertheless, legal, political, and operational constraints are hampering their implementation.


Assuntos
Financiamento Governamental , Financiamento da Assistência à Saúde , Equador , Reforma dos Serviços de Saúde
6.
Trop Med Int Health ; 19(10): 1267-75, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25040259

RESUMO

OBJECTIVES: To evaluate the household use of insecticide consumer products to kill mosquitoes and other insect pests, as well as the expenditures for using these products, in a dengue-endemic area of México. METHODS: A questionnaire was administered to 441 households in Mérida City and other communities in Yucatán to assess household use of insecticide consumer products. RESULTS: A total of 86.6% of surveyed households took action to kill insect pests with consumer products. The most commonly used product types were insecticide aerosol spray cans (73.6%), electric plug-in insecticide emitters (37.4%) and mosquito coils (28.3%). Mosquitoes were targeted by 89.7% of households using insecticide aerosol spray cans and >99% of households using electric plug-in insecticide emitters or mosquito coils. Products were used daily or every 2 days in most of the households for insecticide aerosol spray cans (61.4%), electric plug-in insecticide emitters (76.2%) and mosquito coils (82.1%). For all products used to kill insect pests, the median annual estimated expenditure per household that took action was 408 Mexican pesos ($MXN), which corresponded to approximately 31 $US. These numbers are suggestive of an annual market in excess of 75 million $MXN (>5.7 million $US) for Mérida City alone. CONCLUSION: Mosquitoes threaten human health and are major nuisances in homes in the study area in México. Households were found to have taken vigorous action to kill mosquitoes and other insect pests and spent substantial amounts of money on insecticide consumer products.


Assuntos
Culicidae , Dengue , Características da Família , Gastos em Saúde , Insetos Vetores , Inseticidas , Controle de Mosquitos/métodos , Animais , Dengue/prevenção & controle , Doenças Endêmicas , Feminino , Humanos , Inseticidas/economia , Masculino , México , Controle de Mosquitos/economia , Inquéritos e Questionários
7.
PLoS One ; 19(4): e0302293, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38640122

RESUMO

Smoking is a worldwide epidemic and increased prices are one of the most cost-effective measures to reduce tobacco consumption. This article aims to estimate the price and income elasticity of cigarettes for different population groups in Ecuador. The National Survey of Urban and Rural Household Income and Expenditures (ENIGHUR) 2011-2012 was used, which has information on household cigarette consumption and its sociodemographic characteristics. Deaton's Almost Ideal Demand System, which decouples the effect of quality on the price of the good, was applied. The elasticities were calculated for several groups: urban/rural, income levels (tertiles), education level, sex and age ranges of the household head, and frequency of cigarette purchases in households. The estimated price elasticity nationwide is -0.89 and the income elasticity is 0.41, both statistically significant. Households headed by women (-2.22) are more sensitive to an increase in cigarette prices than those headed by men (-0.65) and households headed by people between 20 and 40 years of age (-2.32) have a higher price elasticity compared to country-level estimations. Differences within other groups are not statistically significant.


Assuntos
Impostos , Produtos do Tabaco , Masculino , Humanos , Feminino , Equador/epidemiologia , Comércio , Fatores Socioeconômicos , Elasticidade
8.
mBio ; : e0134724, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39189787

RESUMO

Clostridioides difficile infection (CDI) causes alterations in the intestinal microbiota, frequently associated with changes in the gut metabolism of bile acids and cholesterol. In addition to the impact on microbiome composition and given the metabolic changes occurring during CDI, our work focuses on the importance to know the effects at the local and systemic levels, both during the infection and its treatment, by paying particular attention to plasma lipid metabolism due to its relationship with CDI pathogenesis. Specific changes, characterized by a loss of microbial richness and diversity and related to a reduction in short-chain acid-producing bacteria and an increase in bile salt hydrolase-producing bacteria, were observed in the gut microbiota of CDI patients, especially in those suffering from recurrent CDI (RCDI). However, gut microbiota showed its ability to restore itself after treatment, resembling healthy individuals, in those patients treated by fecal microbiome transfer (FMT), in contrast with those treated with antibiotics, and displaying increased levels of Eubacterium coprostanoligenes, a cholesterol-reducing anaerobe. Interestingly, changes in plasma lipidome revealed a global depletion in circulating lipids in CDI, with the largest impact on cholesteryl esters. CDI patients also showed a specific and consistent decrease in the levels of lipid species containing linoleic acid-an essential fatty acid-which were only partially recovered after antibiotic treatment. Analysis of the plasma lipidome reflects CDI impact on the gut microbiota and its metabolism, evidencing changes in sterol and fatty acid metabolism that are possibly related to specific alterations observed in gut microbial communities of CDI patients. IMPORTANCE: There is increasing evidence about the influence the changes in microbiota and its metabolism has on numerous diseases and infections such as Clostridioides difficile infection (CDI). The knowledge of these changes at local and systemic levels can help us manage this infection to avoid recurrences and apply the best therapies, such as fecal microbiota transfer (FMT). This study shows a better restoration of the gut in FMT-treated patients than in antibiotic-treated patients, resembling healthy controls and showing increased levels of cholesterol-reducing bacteria. Furthermore, it evidences the CDI impact on plasma lipidome. We observed in CDI patients a global depletion in circulating lipids, particularly cholesteryl esters, and a specific decrease in linoleic acid-containing lipids, an essential fatty acid. Our observations could impact CDI management because the lipid content was only partially recovered after treatment, suggesting that continued nutritional support, aiming to restore healthy lipid levels, could be essential for a full recovery.

9.
Int J Med Microbiol ; 303(3): 128-33, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23523477

RESUMO

Epidemiological surveillance of Clostridium difficile infection has gained importance in recent years as a result of the rapid spread of epidemic strains, including hypervirulent strains and strains with reduced susceptibility to antimicrobials. The molecular epidemiology and antimicrobial susceptibility of C. difficile in the reference hospital of the Balearic Islands (Spain) is reported in this study. One hundred isolates of toxigenic C. difficile from different patients were selected using rapid dual EIA screening test. All isolates were characterized through toxin profile, PCR ribotyping and, in addition, multi-locus sequence typing (MLST) was performed on fifty selected strains. MICs to metronidazole, vancomycin, erythromycin and moxifloxacin were also determined. A total of 43 different ribotypes were distinguished, with higher prevalence of ribotype 014 (34%). Twenty one per cent of the isolates expressed binary toxin and it is noteworthy that 62% of these were identified as the hypervirulent ribotype 078, the second most prevalent ribotype found in our hospital (13%). A total of 20 different sequence types (STs) were found, including a new described allele and ST. MLST data showed a clear concordance between some ribotypes and STs, mainly represented by ribotype 014/ST-2, ribotype 078/ST-11 and ribotype 001/ST-3. Phylogenetic analysis also revealed that most of the isolates were genetically related, forming a large clonal complex. Finally, ribotypes 078 (ST-11) and 001 (ST-3) were associated with higher resistance to erythromycin and to erythromycin and moxifloxacin, respectively. All these data suggest that the combination of ribotyping and MLST is a good tool for the surveillance of the changing epidemiology of C. difficile. A wide dissemination of clones has been observed in our setting, ribotype 014 (ST-2) being the most prevalent followed by the hypervirulent ribotype 078 (ST-11) and ribotype 001 (ST-3), their spread in our setting probably influenced by their higher resistance.


Assuntos
Técnicas de Tipagem Bacteriana , Clostridioides difficile/classificação , Clostridioides difficile/genética , Infecções por Clostridium/epidemiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana , Antibacterianos/farmacologia , Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/microbiologia , Infecção Hospitalar/microbiologia , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Espanha/epidemiologia , Centros de Atenção Terciária
10.
J Antimicrob Chemother ; 65(3): 474-8, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20071364

RESUMO

OBJECTIVES: To study the prevalence, nature, involved genetic elements and epidemiology of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and Pseudomonas putida isolated in a Spanish hospital between 2005 and 2008. METHODS: Etests were used for susceptibility testing and screening for MBLs, confirmed through bla(VIM) PCRs and sequencing. Clonal relatedness was evaluated by PFGE and multilocus sequence typing (MLST). MBL-carrying plasmids were characterized by restriction fragment length polymorphism, Southern blot and electroporation. MBL genetic elements were studied by cloning and sequencing. RESULTS: MBL-producing P. putida was detected in eight patients (one clone each; two harbouring bla(VIM-1) and six harbouring bla(VIM-2)), representing 14% of all the infections by the P. putida/fluorescens group. MBLs were detected in only 0.3% of P. aeruginosa infections (11 patients) during the same period. PFGE revealed four P. aeruginosa clones: one producing bla(VIM-13) (two patients); and three producing bla(VIM-2) (two patients, six patients and one patient, respectively). MLST indicated that the VIM-13 clone was the internationally spread sequence type (ST)235, while the major VIM-2 lineage corresponded to ST179, which is associated with chronic respiratory infections. The VIM-1 integron was shown to have both plasmid and chromosomal location, while the VIM-13 integron was only chromosomal. The VIM-2 integron was located in the same transposon (Tn402/Tn5053-like) in all P. aeruginosa and P. putida isolates, suggesting its crucial role in the dissemination of VIM-2. CONCLUSIONS: The high diversity and proportion of MBL-positive P. putida suggests an environmental reservoir of these resistance determinants. Dissemination of these multidrug resistance elements to successful P. aeruginosa clones presents a major epidemiological and clinical threat.


Assuntos
Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla , Transferência Genética Horizontal , Infecções por Pseudomonas/epidemiologia , Pseudomonas aeruginosa/enzimologia , Pseudomonas putida/enzimologia , beta-Lactamases/biossíntese , Técnicas de Tipagem Bacteriana , Southern Blotting , Análise por Conglomerados , Infecção Hospitalar/microbiologia , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Hospitais , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Dados de Sequência Molecular , Plasmídeos , Polimorfismo Genético , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/classificação , Pseudomonas aeruginosa/genética , Pseudomonas putida/classificação , Pseudomonas putida/genética , Mapeamento por Restrição , Análise de Sequência de DNA , Espanha/epidemiologia , beta-Lactamases/genética
11.
J Antimicrob Chemother ; 65(7): 1399-404, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20435779

RESUMO

OBJECTIVES: Biofilm growth, mucoid phenotype and proficient resistance development by hypermutable strains dramatically limit the efficacy of current therapies for Pseudomonas aeruginosa chronic respiratory infection (CRI) in cystic fibrosis (CF) patients. We evaluated the activity of the new cephalosporin CXA-101, ceftazidime, meropenem and ciprofloxacin against biofilms of wild-type PAO1 and its mucoid (mucA), hypermutable (mutS) and mucoid-hypermutable derivatives, and analysed the capacity of these strains to develop resistance during planktonic and biofilm growth. METHODS: MICs and MBCs were determined by microdilution, and mutant frequencies were determined at 4x and 16x the MICs. Biofilms were formed using a modified Calgary device and were incubated for 24 h with 0x, 1x, 4x or 16x the MIC of each antibiotic. Biofilms were plated, and total cells and resistant mutants enumerated. RESULTS: CXA-101 showed concentration-independent biofilm bactericidal activity, being the most potent agent tested at 1x the MIC for wild-type, mucoid and hypermutable strains. The spontaneous mutant frequencies for CXA-101 were extremely low (<5 x 10(-11)), even for the hypermutable strain at low concentrations (4x the MIC), in sharp contrast to the other antipseudomonal agents. Accordingly, mutants resistant to 4x the MIC of CXA-101 did not emerge in biofilms for any of the strains/concentrations tested. CONCLUSION: These data strongly suggest that resistance to CXA-101 (at least 4x the MIC) cannot be driven by single-step mutations, either in planktonic or in biofilm growth. CXA-101 shows encouraging properties for the treatment of CRI by P. aeruginosa, which need to be further evaluated in animal models and pertinent clinical trials.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Infecções Respiratórias/microbiologia , Contagem de Colônia Microbiana , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Mutação , Fenótipo , Pseudomonas aeruginosa/fisiologia
12.
Salud Publica Mex ; 52(1): 61-9, 2010.
Artigo em Espanhol | MEDLINE | ID: mdl-20464255

RESUMO

OBJECTIVE: To analyze experiences of heterosexual Mexican people living with HIV (PLWHA) related to the exercise of their sexual and reproductive rights. MATERIAL AND METHODS: Qualitative study based on 40 in-depth interviews with PLWHA in four Mexican States. RESULTS: Lack of support and counseling limits the exercise of sexual and reproductive rights by PLWHA, especially women. Principal limitations include feelings of frustration and confusion, fear of re-infection, scanty information, lack of power to negotiate condom use, social stigma and discrimination, and limited access to services and adequate technologies. CONCLUSION: To increase awareness and exercise of rights by PLWHA it is necessary to: improve sexual education; promote processes of cultural change to combat gender inequality and stigma and discrimination; and provide timely and scientific information about HIV prevention.


Assuntos
Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Heterossexualidade/psicologia , Direitos Humanos , Comportamento Sexual , Adulto , Confusão , Escolaridade , Medo , Feminino , Frustração , Infecções por HIV/prevenção & controle , Humanos , Masculino , México , Pessoa de Meia-Idade , Preconceito , Reprodução , Sexo Seguro , Parceiros Sexuais/psicologia
13.
Microorganisms ; 8(12)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348645

RESUMO

Since they were discovered, amyloids have proven to be versatile proteins able to participate in a variety of cellular functions across all kingdoms of life. This multitask trait seems to reside in their ability to coexist as monomers, aggregates or fibrillar entities, with morphological and biochemical peculiarities. It is precisely this common molecular behaviour that allows amyloids to cross react with one another, triggering heterologous aggregation. In bacteria, many of these functional amyloids are devoted to the assembly of biofilms by organizing the matrix scaffold that keeps cells together. However, consistent with their notion of multifunctional proteins, functional amyloids participate in other biological roles within the same organisms, and emerging unprecedented functions are being discovered. In this review, we focus on functional amyloids reported in gram-positive bacteria, which are diverse in their assembly mechanisms and remarkably specific in their biological functions that they perform. Finally, we consider cross-seeding between functional amyloids as an emerging theme in interspecies interactions that contributes to the diversification of bacterial biology.

14.
Travel Med Infect Dis ; 37: 101683, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32335208

RESUMO

BACKGROUND: Neurocysticercosis (NCC) is the most common parasitic neurological disease worldwide and a major cause of epilepsy. Spain is the country reporting the highest number of NCC imported cases in Europe. METHODOLOGY: Retrospective case series of NCC patients registered in the +REDIVI Network from October 1, 2009 to July 2018. A specific questionnaire, including clinical and diagnostic characteristics, was created and sent to the collaborator centers. RESULTS: 46 cases were included in the analysis. 55% were male, mean age of 40 years. 95.6% were migrants. The median duration since migration from an endemic area was 10 years. Predominant nationalities were Ecuadorians (50%) and Bolivians (30.4%). Frequent locations were parenchymal (87%), subarachnoid (26.1%) and intraventricular cysts (10.9%). Serological analysis was performed in 91.3%, being 54.8% positive. Most prevalent clinical manifestations were persistent headache (60.9%), epilepsy (43.5%) and visual changes (13%). Patients were mainly treated with albendazole (76.1%), corticosteroids (67.4%), and anticonvulsionants (52.2%). 82.5% had a favorable clinical outcome. CONCLUSIONS: Most NCC cases were long-standing migrants. Few clinical differences were observed depending on the cysticerci location. The treatment was often not according to current recommendations, and no uniform criteria were followed when it came to the therapeutic regimen. NCC case management in Spain (including clinician awareness and laboratory capacity improvements) needs to be strengthened.


Assuntos
Cisticercose , Neurocisticercose , Adulto , Europa (Continente) , Humanos , Masculino , Estudos Retrospectivos , Espanha
15.
Sci Rep ; 10(1): 1000, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31969664

RESUMO

Bacterial physiology and adaptation are influenced by the exopolysaccharides (EPS) they produce. These polymers are indispensable for the assembly of the biofilm extracellular matrix in multiple bacterial species. In a previous study, we described the profound gene expression changes leading to biofilm assembly in B. cereus ATCC14579 (CECT148). We found that a genomic region putatively dedicated to the synthesis of a capsular polysaccharide (eps2) was overexpressed in a biofilm cell population compared to in a planktonic population, while we detected no change in the transcript abundance from another genomic region (eps1) also likely to be involved in polysaccharide production. Preliminary biofilm assays suggested a mild role for the products of the eps2 region in biofilm formation and no function for the products of the eps1 region. The aim of this work was to better define the roles of these two regions in B. cereus multicellularity. We demonstrate that the eps2 region is indeed involved in bacterial adhesion to surfaces, cell-to-cell interaction, cellular aggregation and biofilm formation, while the eps1 region appears to be involved in a kind of social bacterial motility. Consistent with these results, we further demonstrate using bacterial-host cell interaction experiments that the eps2 region is more relevant to the adhesion to human epithelial cells and the zebrafish intestine, suggesting that this region encodes a bacterial factor that may potentiate gut colonization and enhance pathogenicity against humans.


Assuntos
Bacillus cereus/genética , Proteínas de Bactérias/genética , Matriz Extracelular de Substâncias Poliméricas/genética , Regulação Bacteriana da Expressão Gênica , Polissacarídeos Bacterianos/genética , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Genômica , Polissacarídeos Bacterianos/metabolismo
16.
Artigo em Inglês | MEDLINE | ID: mdl-31969984

RESUMO

Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneficial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm and to differentiate into the offensive or defensive features. We report that floating and biofilm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, biofilm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxification machinery and production of secondary metabolites. This strategy contributes to defend biofilm cells from competitors. However, floating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.


Assuntos
Bacillus cereus/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Aderência Bacteriana , Linhagem Celular , Metabolismo Energético , Fermentação , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Células HeLa , Humanos , Proteômica , Espécies Reativas de Oxigênio/metabolismo , Análise de Sequência de RNA , Esporos Bacterianos/metabolismo
17.
Antimicrob Agents Chemother ; 53(4): 1552-60, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19188376

RESUMO

Azithromycin (AZM) has shown promising results in the treatment of Pseudomonas aeruginosa chronic lung infections such as those occurring in cystic fibrosis (CF) patients. We evaluated the effect of hypermutation and alginate hyperproduction on the bactericidal activity and resistance development to AZM in P. aeruginosa biofilms. Strains PAO1, its microcA mutant (PAOMA), and their respective mutS-deficient hypermutable derivatives (PAOMS and PAOMSA) were used. Biofilms were incubated with several AZM concentrations for 1, 2, 4, or 7 days, and the numbers of viable cells were determined. During the first 2 days, AZM showed bactericidal activity for all the strains, but in extended AZM incubation for strain PAOMS and especially strain PAOMSA, a marked increased in the number of viable cells was observed, particularly at 4 microg/ml. Biofilms formed by the lineages recovered from the 7-day experiments showed enhanced AZM resistance. Furthermore, most of the independent lineages studied, including those obtained from biofilms treated with AZM concentrations as low as 0.5 microg/ml, showed MexCD-OprJ hyperexpression and mutations in nfxB. The role of nfxB mutation in AZM resistance was further confirmed through the characterization of nfxB and mexD knockout mutants. Results from this work show that, although AZM exhibits bactericidal activity against P. aeruginosa biofilms, resistant mutants are readily selected and that, furthermore, they frequently show cross-resistance to other unrelated antipseudomonal agents such as ciprofloxacin or cefepime but hypersusceptibility to others such as imipenem or tobramycin. Therefore, these results should help guide the selection of appropriate antipseudomonal therapies in CF patients under AZM maintenance treatment.


Assuntos
Antibacterianos/farmacologia , Azitromicina/farmacologia , Proteínas de Bactérias/fisiologia , Biofilmes/efeitos dos fármacos , Proteínas de Ligação a DNA/fisiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Fatores de Transcrição/fisiologia , Proteínas de Bactérias/genética , Cefepima , Cefalosporinas/farmacologia , Ciprofloxacina/farmacologia , Fibrose Cística/tratamento farmacológico , Proteínas de Ligação a DNA/genética , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Proteínas de Membrana Transportadoras/fisiologia , Testes de Sensibilidade Microbiana , Proteína MutS de Ligação de DNA com Erro de Pareamento/genética , Mutação , Pseudomonas aeruginosa/genética , Fatores de Transcrição/genética
18.
Angle Orthod ; 79(1): 127-32, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19123696

RESUMO

OBJECTIVE: To evaluate the effects of water and saliva contamination on shear bond strength of brackets bonded with a moisture-tolerant light cure system. MATERIALS AND METHODS: Brackets were bonded to 240 bovine lower incisors divided into 12 groups. Four bonding procedures were evaluated, including (1) TSEP/Transbond XT, (2) TMIP/ Transbond XT, (3) TSEP/Transbond PLUS, and (4) TMIP/Transbond PLUS, each under three different bonding conditions: without contamination, with water contamination, and with saliva contamination. Shear bond strength was measured with a universal testing machine. The adhesive remnant on the teeth was quantified with the use of image analyzing equipment. RESULTS: Without contamination, bond strengths for the four procedures were similar (P > .05). TSEP/Tranbond PLUS and TMIP/Transbond PLUS left significantly less adhesive on the teeth after debonding than TSEP/Transbond XT and TMIP/Transbond XT (P < .008). Bond strength and adhesive remaining for TMIP/Transbond XT contaminated with water or saliva showed significantly worse performance than the other procedures evaluated (P < .008). Contamination (with water or saliva) did not affect either bond strength or adhesive remaining on the teeth for TSEP/ Transbond XT, TSEP/Transbond PLUS, or TMIP/Transbond PLUS (P > .017), although for TMIP/ Transbond XT, both variables showed significant reductions after contamination (P < .017). CONCLUSION: TSEP/Transbond PLUS, TMIP/Transbond PLUS, and TSEP/Transbond XT showed greater tolerance to wet conditions than was shown by TMIP/Transbond XT.


Assuntos
Permeabilidade do Esmalte Dentário , Cura Luminosa de Adesivos Dentários , Braquetes Ortodônticos , Cimentos de Resina , Animais , Bis-Fenol A-Glicidil Metacrilato/química , Bovinos , Descolagem Dentária , Análise do Estresse Dentário , Etanol , Metacrilatos , Distribuição Aleatória , Cimentos de Resina/química , Saliva , Resistência ao Cisalhamento , Água , Molhabilidade
19.
Braz J Microbiol ; 40(3): 563-8, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24031400

RESUMO

The present study aimed to evaluate the ability for biotransformation of the Diels-Alder adduct tricyclo[6.2.1.0(2,7)]undeca-4,9-dien-3,6-dione (1) and two synthetic derivatives by the saprobe fungus Mucor ramosissimus Samutsevitsch. Products from oxidation, isomerization and, regioselective and enantioselective reduction were achieved.

20.
Psychiatry Res ; 158(3): 316-23, 2008 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-18258307

RESUMO

The objective was to evaluate the relationship among symptomatology, awareness of illness, and attributional style in patients with schizophrenia. Fifty-six patients who were receiving outpatient psychiatric care gave their consent to fill out questionnaires designed to assess symptomatology, awareness of illness, and self-serving bias (SSB), which is a tendency to excessively attribute positive events to internal causes. Questionnaires were successfully completed by 44 patients (31 males and 13 females between the ages of 18 and 62). The following measures were used: Positive and Negative Symptoms Scale (PANSS), Scale to assess Unawareness of Mental Disorders (SUMD), and Attributional Style Questionnaire (ASQ). The results showed that emotional discomfort, which is directly related to the depressive syndrome, and the cognitive syndrome were significantly associated with a reversed SSB (tendency to excessively attribute positive events to external causes and negative events to internal causes). Emotional discomfort accounted for 23.5% of the variance in reversed SSB and the cognitive syndrome for 9.7% of the variance in reversed SSB. No relationship was found to exist between unawareness of illness and SSB. These findings reveal that in patients with schizophrenia, reversed SSB is closely related to the presence of depressive symptoms.


Assuntos
Atitude Frente a Saúde , Conscientização , Controle Interno-Externo , Esquizofrenia/diagnóstico , Psicologia do Esquizofrênico , Adolescente , Adulto , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Transtorno Depressivo/diagnóstico , Transtorno Depressivo/psicologia , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA