No description available.

no / Pseudomonas aeruginosa is a versatile pathogen associated with a broad spectrum of infections in humans. In healthcare settings the bacterium is an important cause of infection in vulnerable individuals including those with burns or neutropenia or receiving intensive care. In these groups morbidity and mortality attributable to P. aeruginosa infection can be high. Management of infections is difficult as P. aeruginosa is inherently resistant to many antimicrobials. Furthermore, treatment is being rendered increasingly problematic due to the emergence and spread of resistance to the few agents that remain as therapeutic options. A notable recent development is the acquisition of carbapenemases by some strains of P. aeruginosa. Given these challenges, it would seem reasonable to identify strategies that would prevent acquisition of the bacterium by hospitalised patients. Environmental reservoirs of P. aeruginosa are readily identifiable, and there are numerous reports of outbreaks that have been attributed to an environmental source; however, the role of such sources in sporadic pseudomonal infection is less well understood. Nevertheless there is emerging evidence from prospective studies to suggest that environmental sources, especially water, may have significance in the epidemiology of sporadic P. aeruginosa infections in hospital settings, including intensive care units. A better understanding of the role of environmental reservoirs in pseudomonal infection will permit the development of new strategies and refinement of existing approaches to interrupt transmission from these sources to patients. / None

No description available.

An interview study was undertaken to explore Swedish broiler producers´ views for the potential of hops (H. lupulus L.) to reduce reliance on ionophorous coccidiostats in broiler production. The design was a mixed methodology between grounded theory and case study with a semi structured interview method. Nine producers, four using ionophorous coccidiostats and five without reliance in production accepted interview. During interviews participants were presented to research conducted with hops in production and consequences from ionophores in production. All participants thought the risk from pathogen pressure was too great to cut reliance in intensive production owed to the lower efficacy of hops. Therefore owed to how actors in the Swedish food system behave only small producers with enough economical freedom for reduced stocking densities were regarded to be able to uphold animal health with hops. Six parameters within food systems were regarded as leverage points for a potential of hops in production on a larger societal scale if encouraging a more extensive nationwide production system. Those were: purchase will, small local production, increased responsibility within trade, law, elevated consumers and research. Law was seen as a necessity to enforce all other denominators since economical in food systems tend to override social and ecological dimensions. Consequences from power struggle in food systems disfavoring producers has although resulted in a great distrust towards other system actors such as consumers, legal institutions or wholesalers. That has created a reluctance to interact with other system actors even for common goals. A stronger position to other actors in food systems was regarded as increasing a meaningful outcome from interaction. Four parameters emerged as impacting power relations in a system the most: Purchase will, contracts, own designed production and law. Favorable purchase will and law would contribute the most for increasing adaptivity for alternatives in production by impacting on power relations. No producers had observed indicators of bacterial resistance from ionophorous coccidiostat usage. Lack of research for many years in the field was troublesome for how to develop the enterprise according to participants. Especially in relation to Norway that has abolished the static use of ionophorous coccidiostats in production. About half of the participants although regarded a shift in research towards consequences from intensive production as equally important as focusing on alternative antimicrobials.

A contaminação de equipamentos e materiais hospitalares por microrganismos potencialmente infecciosos e altamente resistentes aos antibióticos incitam grupos de pesquisa e industrias ao redor do mundo a produzir novos materiais, e que estes possuam propriedades capazes de inibir ou eliminar (quase que completamente) a permanência desses patógenos sobre sua superfície. O objetivo deste trabalho foi avaliar a citotoxicidade da liga níquel-berílio quando em contato com as cepas bacterianas de Staphylococcus aureus (ATCC 25932), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (amostra clínica) e Escherichia coli (ATCC 11775), após diferentes períodos de incubação, e em contato com a linhagem celular NCTC Clone 929, célula de tecido conectivo de camundongo. Para realização destes ensaios, foram confeccionados corpos de prova da liga níquel-berílio, com aproximadamente 10,0 mm e diâmetro e 3,0 mm de espessura. Para metodologia de citotoxicidade as células bacterianas preparou-se um inóculo bacteriano de 109 Unidades Formadoras de Colônia por mililitro. Para cada bactéria, um inóculo bacteriano foi preparado e deste, 40 &#956l foram aplicados em um swab estéril e espalhado no corpo de prova, onde foram introduzidos em placas de Petri, deixados a temperatura 20°C, por diferentes períodos de exposição (1, 3, 6, 9, 12, 18, 24 e 72 horas). Este teste foi realizado em triplicata. Após cada período de tempo, os corpos de prova eram pressionados contra o meio de cultura Agar Mueller-Hinton, em dez diferentes pontos da placa. O método de difusão em Agar foi utilizado para verificar a citotoxicidade da liga níquel-berílio à linhagem celular NCTC clone 929. Os resultados obtidos demonstram uma maior resistência a liga níquel-berílio das bactérias gram-positivas (S. aureus e S. epidermidis) quando comparadas com as gram-negativas (P. aeruginosa, K. pneumonia e E. coli). Destas últimas citadas, a E. coli foi a única que sobreviveu até a sexta hora de exposição, quando em contato de uma hora com o corpo de prova. Todavia, os S. aureus e S. epidermidis foram capazes de resistir até a décima segunda hora em contato com a liga níquel-berílio. Contudo, a partir deste período de incubação, nem mesmo os estafilococos toleraram a presença desses íons. Quando analisados os resultados de citotoxicidade, a liga não apresentou qualquer efeito citotóxico as células NCTC clone 929, sendo classificadas como índice de zona (IZ) zero. Os dados obtidos demonstram que a liga possui propriedades antibacteriana contra as células bacterianas testadas e que não possui nenhum efeito tóxico à linhagem celular NCTC clone 929. Além disso, a liga NiBe mostrou-se mais citotóxica contra as bactérias gram-negativas. / The contamination of equipment and hospital supplies for potentially infectious microorganisms and highly resistant to antibiotics encourage research groups and industries around the world to produce new materiais, and they have properties able to inhibit or eliminate (almost completely) to stay these pathogens on its surface. The objective of this study was to evaluate the cytotoxicity of nickel-beryllium alloy when in contact with the bacterial strains of Staphylococcus aureus (ATCC 25932), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (clinical sample) and Escherichia coli (ATCC 11775), after different periods of incubation, and in contact with the cell line NCTC Clone 929, connective tissue of mouse cell. For these assays were prepared coupons of nickel-beryllium alloy, with approximately 10.0 mm and diameter and 3.0 mm thick. For cytotoxicity methodology bacterial cells prepared in a bacterial inoculum of 109 Colony-Forming Units per milliliter. For each bacterium, a bacterial inoculum was prepared and this, 40 &#956l were applied in a sterile swab and spread in the coupons, which were introduced in Petri dishes left at 20°C temperature, for different exposure times (1, 3, 6, 9, 12, 18, 24 and 72 hours). This test was performed in triplicate. After each time period, the samples were pressed against the culture medium Mueller-Hinton Agar at ten different points of the plate. The agar diffusion method was used to assess the cytotoxicity of nickel-beryllium alloy to clone cell line NCTC 929. The results show a greater resistance to nickel-beryllium alloy of gram-positive bacteria (S. aureus and S. epidermidis) compared to gram-negative (Pseudomonas aeruginosa, K. pneumoniae and E. coli). Of the latter mentioned, E. coli was the only one that survived until the sixth hour of exposure when contact an hour with the alloy. However, S. aureus and S. epidermidis were able to hold out until the twelfth time in contact with nickel-beryllium alloy. However, from this incubation period, even staphylococci tolerated the presence of these ions. When analyzed the results of cytotoxicity, the alloy showed no cytotoxic effect the NCTC clone 929 cells, are classified as zone index (IZ) zero. The data obtained show that the alloy possesses antibacterial properties against the tested bacterial cells and has no toxic effect on the cell line NCTC clone 929. Furthermore, \'Ni\'\'Be\' alloy was more cytotoxic against gram-negative bacteria.

Atualmente, no Brasil, a produção de enzimas do tipo KPC constitui o principal mecanismo de resistência aos carbapenêmicos em Klebsiella pneumoniae, contribuindo para a endemicidade hospitalar da espécie. No presente estudo, foi caracterizada a produção de KPC em 38 enterobactérias que foram diferençadas entre os grupos CESP (enterobactérias com produção induzida da βlactamase AmpC, ex., Enterobacter spp., Serratia marcescens e Morganella morganii) e não CESP (ex., Klebsiella pneumoniae, Escherichia coli e Proteus mirabilis). pertencendo a isolados recuperados de pacientes colonizados e/ou apresentando infecção urinária, pneumonia ou bacteremia, em três centros médicos de três diferentes regiões do Brasil (Amazonas, Mato grosso, Minas Gerais), durante 2008-2013. Os isolados apresentaram resistência para cefalosporinas de amplo espectro (86,8 - 94,7%), cefoxitina (86,8%), ertapenem (89,4%), imipenem (89,4%), meropenem (84,2%), amicacina (86,8%), ciprof1oxacina (84,2%), tigeciclina (42,1 %, CIM50= 2 µg/ml), sulfametoxazol/trimetoprim (SXT, 60,5%) e gentamicina (57,8%). Entre bactérias do grupo CESP, os isolados de S. marcescens apresentaram sensibilidade para fosfomicina (CIM50= 8 µg/mL) e sulfametoxazol-trimetoprim (CIM50= 1/19 µg/mL). A produção de carbapenemase foi confirmada pelo teste de Hodge modificado e por inibição por acido fenil borônico em 76,31 e 73,68% dos isolados do grupo CESP e não CESP, respectivamente. A presença do gene blaKPC-2 foi confirmada em 78,9% dos isolados clinicos e variantes do gene blaCTX-M foram identificados em 57,89% das cepas. Cepas de S. marcescens e E. aerogenes clonalmente relacionadas por ERIC-PCR foram associadas a surtos de infecção nosocomial. Resultados do presente estudo confirmam que a produção de KPC no Brasil, ocorre em uma grande variedade de espécies de enterobactérias sendo frequentemente associada com a co-produção de ESBLs do tipo CTX-M, o que poderia favorecer a endemicidade com o subseqüente estabelecimento de surtos de infecção. Um dado relevante, foi à alta resistência a fosfomicina (66,66%) associada à presença do gene fosA2 em cepas de E. aerogenes e K. pneumoniae produtores de KPC-2. / Currently, in Brazil, the production of KPC-type enzymes is considered the main mechanism of carbapenem resistance in Klebsiella pneumoniae, which has contributed for the nosocomial endemicity of this specie. In this study, the KPC production was characterized in 38 Enterobacteriaceae isolates differenced among CESP (Enterobacteriaceae with inducible production of AmpC-type β-lactamase, i.e., Enterobacter spp., Serratia marcescens and Morganella morganii) and not CESP (Klebsiella pneumoniae, Escherichia coli e Proteus mirabilis) groups recovered from colonized patients and/or with urinary tract infection, pneumonia or bacteremia, in three medicai centers from different regions of Brazil (Amazonas, Mato Grosso, Minas Gerais) during 2011-2013. The isolates were resistant to broad-spectrum cephalosporins (86.8 - 94.7%), cefoxitin (86.8%), ertapenem (89.4%), imipenem (89.4%), meropenem (84.2%), amikacin (86.8%), ciprofloxacin (84.2%), tigecycline (42.1 %, MIC50 = 2 µg/mL), trimethoprim-sulfamethoxazole (SXT, 60.5%) and gentamicin (57.8%). S. Marcescens isolates exhibited additional susceptibility to fosfomycin (MIC50 = 8 µg/mL) and sulfamethoxazole-trimethoprim (MIC50 = 1/19 µg/mL). Carbapenemase production was confirmed by Hodge modified test and inhibition by phenyl boronic acid in 76.31 and 73.68% of CESP and no CESP isolates, respectively. In fact, the presence of the blaKPC-2 gene was confirmed in 78.9% of enterobacterial isolates, whereas blaCTX-M ESBL gene variants were identified in 57.89% of the strains. S. Marcescens and E. aerogenes isolates were clonally related by ERIC-PCR being associated with outbreaks of nosocomial infection. Results of this study confirm that the production of KPC in Brazil occurs in a variety of species of Enterobacteriacea producing CTX-M-rype ESBLs, favoring the endemicity and the establisbment of outbreaks. A relevant finding was the high resistance to fosfomycin (66.66%) associated with the presence of the fosA2 gene in KPC-2-producing E. aerogenes and K. pneumoniae strains.

Submitted by admin tede (tede@pucgoias.edu.br) on 2016-08-17T14:16:30Z No. of bitstreams: 1 SILVIO JOSE DE QUEIROZ.pdf: 8869081 bytes, checksum: 28d26b617f56db3485bb151beb37b8ad (MD5) / Made available in DSpace on 2016-08-17T14:16:30Z (GMT). No. of bitstreams: 1 SILVIO JOSE DE QUEIROZ.pdf: 8869081 bytes, checksum: 28d26b617f56db3485bb151beb37b8ad (MD5) Previous issue date: 2010-08-09 / Infections caused by multiresistant microorganisms are associated with bacteria acquired in the hospital environment. The selective pressure of antimicrobials is an important factor in the selection and spread of resistance genes in the environment. The use of different molecules produced by living organisms has demonstrated activity against microorganisms. OBJECTIVES: To assess the activity of the crude venom of Bothrops moojeni on gram-negative bacteria producing and non producing metallo- -lactamase and -lactamases with wide spectrum, to identify component (s) of the poison with activity against gram-negative bacteria producing and non producing metallo- -lactamase and -lactamases with wide spectrum and to identify the antibacterial activity of crude venom of the snake B. moojeni in gram negative non-fermentative and fermentative glucose producing different enzymes to degrade -lactams. METHODOLOGY: The poison used was extracted from snake B. moojeni kept on the collection of the Center for Biological Studies and Research (CEPB) Catholic University of Goias Micro-organisms used in this study were obtained from the American Type Culture Collection and Bank of Microorganisms, Laboratory of Clinical Microbiology and MSc in Environmental and Health Sciences at the Catholic University of Goias, including Acinetobacter baumannii (blaIMP2), Pseudomonas aeruginosa (ATCC 27853), Pseudomonas aeruginosa blaIMP1, blaVIM1, blaVIM2, blaSPM1 and producing carbapenemase No. 278 bank) Escherichia coli (ATCC 25922 and ATCC 35 218), Klebisiella pneumoniae (ATCC 700603). The test was conducted with the crude venom applied on disk diffusion in different dilutions. Protein concetration was determined for each venon sample, buy using the Bradford. RESULTS: The microbiological test showed that the venom demonstrated antimicrobial activity, both for producing bacteria and non-producing -lactamase and -lactamases bactérias with wide spectrum and that this activity is probably due to the action of L-amino acid oxidase. CONCLUSIONS: Different concentrations of crude venom of the snake B. moojeni inhibited growth of gram-negative bactéria producing ond non producing metallobeta- lactamase and extende spectrum beta-lactamese ond the size of the allo of growth inhibited diminished when decreased concentration of the crud venon and consequentley the decrese of concentration of protein, demonstrating that the effect of crude venom was dose dependent. / As infecções causadas por microrganismos multirresistentes estão associadas com bactérias adquiridas no meio ambiente hospitalar. A pressão seletiva dos antimicrobianos é um importante fator de seleção e disseminação dos genes de resistência no meio ambiente. O uso de moléculas produzidas por diferentes seres vivos tem demonstrado atividade contra microrganismos. OBJETIVOS: Avaliar a atividade do veneno bruto da Bothrps moojeni sobre bactérias gram-negativas produtoras e não produtoras de metalo- -lactamase e de -lactamases de espectro ampliado, identificar o(s) componente(s) do veneno com atividade contra bactérias gram-negativas produtoras e não produtoras de metalo- -lactamase e -lactamases de espectro ampliado e identificar a atividade antibacteriana do veneno bruto da serpente B. moojeni em bactérias gram negativas fermentadoras e não fermentadoras de glicose produtoras de diferentes enzimas degradadoras de -lactâmicos. METODOLOGIA: O veneno utilizado foi extraído das serpentes B. moojeni, mantidas no serpentário do Centro de Estudos e Pesquisas Biológicas (CEPB) da Pontifícia Universidade Católica de Goiás. Os microrganismos utilizados neste estudo foram obtidos da “American Type Culture Collection” e do Banco de Microrganismos do Laboratório de Microbiologia Clínica e do Mestrado em Ciências Ambientais e Saúde da Pontifícia Universidade Católica de Goiás, sendo Acinetobacter baumannii (blaIMP2), Pseudomonas aeruginosa (ATCC 27853), Pseudomonas aeruginosa blaIMP1, blaVIM1, blaVIM2, blaSPM1 e produtora de carbapenemase banco n° 278) Escherichia. coli (ATCC 25922 e ATCC 35218), Klebisiella pneumoniae (ATCC 700603). O ensaio foi realizado com o veneno bruto aplicado sobre disco de difusão em diferentes diluições. A partir das amostras obtidas, foi realizada a dosagem de proteínas utilizando o método descrito por Bradford. RESULTADOS: O teste microbiológico mostrou que o veneno bruto possui atividade antimicrobiana, tanto para bactérias produtoras como para as não produtoras de metalo- -lactamase e -lactamases de espectro ampliado e que esta atividade se deve possivelmente pela ação da L-aminoácido oxidase. CONCLUSÕES: Diferentes concetrações diluições do veneno bruto da serpente B. moojeni inibiram o crescimento de bactérias gram-negativas produtoras e não produtoras de metalo- -lactamases e -lactamases de espectro ampliado e que o tamanho do alo de inibição do crescimento bacteriano diminuiu na medida em que diminui a concentração do veneno bruto e consequentemente à quantidade de proteínas, demonstrando que o veneno bruto foi dose dependente.

Pseudomonas aeruginosa é um patógeno humano que tem preocupado a comunidade científica pelo aumento da resistência antimicrobiana. Os efeitos provocados pelos antimicrobianos podem levar à ativação de respostas mutagênicas que regulam polimerases de baixa fidelidade, atuando na Síntese Translesão de DNA (TLS). Neste trabalho, avaliamos a resposta de P. aeruginosa frente à Ceftazidima e Ciprofloxacina. Foi observado que Ceftazidima não induz a resposta SOS e mutagênese, diferentemente de Ciprofloxacina. Demonstramos que as três polimerases de TLS estão envolvidas na mutagênese induzida por Ciprofloxacina e peróxido de hidrogênio. Também, observamos que a perda de qualquer uma das polimerases alterou significativamente o espectro de mutações espontâneas e induzidas por Ciprofloxacina e que possuem funções redundantes neste processo mutagênico. Assim, demonstramos que as polimerases de TLS são importantes para a mutagênese induzida por Ciprofloxacina em P. aeruginosa, e podem estar implicadas na mutagênese adaptativa e, consequentemente, na resistência bacteriana. / Pseudomonas aeruginosa is a human pathogen that has worried the scientific community by increasing antimicrobial resistance. The effects caused by the antimicrobial agents may lead to the activation of mutagenic responses that regulate low fidelity polymerases, acting in DNA Transmission Synthesis (TLS). In this work, we evaluated the response of P. aeruginosa to Ceftazidime and Ciprofloxacin. It has been observed that Ceftazidime does not induce the SOS response nor mutagenesis, unlike Ciprofloxacin. We show that the three TLS polymerases are involved in the mutagenesis induced by Ciprofloxacin and hydrogen peroxide. Also, we observed that the loss of any of the polymerases significantly altered the spectrum of spontaneous mutations induced by Ciprofloxacin and that have redundant functions in this mutagenic process. Thus, we have shown that TLS polymerases are important for Ciprofloxacin-induced mutagenesis in P. aeruginosa, and may be implicated in adaptive mutagenesis and consequently bacterial resistance.

La propagation de bactéries à Gram négatif multirésistantes aux antibiotiques représente un problème de santé publique majeur urgent à résoudre car le risque d’un retour à l’ère pré-antibiotique est réel. Parmi les modes de résistance existant, la production de métallo-B-lactamases (MBLs) responsables de l’inactivation des B-lactamines, la famille d’antibiotiques la plus utilisée, représente un challenge thérapeutique.Les travaux décrits dans ce manuscrit concernent la synthèse, la caractérisation et l’évaluation biologique de composés construits autour d’un cœur 2,4-dihydro-3H-1,2,4-triazole-3-thione substitués en deux positions. En se basant sur des études de criblage in silico et des études cristallographiques ayant permis d’identifier ce noyau comme un bon candidat dans le développement d’inhibiteurs de MBLs, la synthèse de différentes séries d’analogues a été entreprise afin d’identifier de nouveaux inhibiteurs pouvant potentiellement atteindre les tests cliniques.Dans un premier temps, une série de composés 4-amino-1,2,4-triazole-3-thione substitués en position 5 a été préparée en suivant des voies de synthèse classiques. Différentes séries ont ensuite été développées en introduisant une diversité structurale et fonctionnelle en position 4. Ces composés ont ensuite été testés sur des enzymes représentatives des 3 sous-classes de MBLs et les plus intéressants ont été évalués sur bactéries résistantes recombinantes.Afin de réaliser une évaluation rapide des produits synthétisés au sein du laboratoire, une méthode de criblage à moyen débit en plaque 96 puits sur cinq MBLs représentatives a été mise au point et validée grâce à l’appui de nos collaborateurs spécialistes des MBLs. / The spread of multiresistant Gram negative bacteria is a growing threat to public health and the risk of return to the pre-antibiotic era is real. Among existing resistance modes, the production of metallo-B-lactamases (MBLs) responsible of the inactivation of B-lactams, the most used family of antibiotics, represents a therapeutical challenge.This manuscript describes the synthesis, characterization and biological evaluation of compounds built on a 2,4-dihydro-3H-1,2,4-triazole-3-thione scaffold substituted on two positions. Based on previous in silico screening and crystallographic studies, which identified this structure as a good candidate for MBLs inhibition, several series have been developed to found new inhibitors that could potentially be amenable to clinical development.First, 1,2,4-triazole-3-thione compounds substituted at position 5 have been prepared following classical pathways. Then, several series have been developed where the structural and functional diversity was introduced at position 4. Compounds have been tested on representative MBLs of the three sub-classes and the most interesting ones on recombinant resistant bacteria.To perform a rapid screening of compounds in the laboratory, a method of medium throughput screening inhibition tests on five MBLs performed in 96-wells plate has also been developed and validated during this study with the help of our collaborators specialists of MBLs

Antibiotic resistance is an ongoing global medical crisis and we are in great need of new antibacterial agents to combat rapidly emerging resistant pathogens. Tigecycline is one of few drugs that have been introduced into medicine during the last two decades. It is a broad-spectrum third generation tetracycline that is active against multidrug-resistant bacteria that cause complicated infections. In this thesis I examined the development of tigecycline resistance in Escherichia coli and associated in vitro and in vivo fitness effects. Selections of spontaneous E. coli mutants revealed relatively high accumulation rates of changes in the multidrug efflux system AcrAB-TolC regulation network and in heptose biosynthesis and transport pathways important for lipopolysaccharide (LPS) synthesis. Both groups of mutations led to reduced susceptibility to tigecycline and slower growth compared to the wild-type bacteria. Additional in vitro fitness assays and in vivo competitions showed that LPS mutants were less fit than efflux mutants, providing a possible explanation for why up-regulation of multidrug efflux pumps is the main tigecycline resistance mechanism reported in clinical isolates. Tigecycline was designed to evade the two most common tetracycline resistance mechanisms conferred by Tet proteins, efflux and ribosomal protection. However, tigecycline is a substrate for the tetracycline modifying enzyme Tet(X). Screening of Tet protein mutant libraries showed that it is possible to select Tet mutants with minimal inhibitory concentrations of tigecycline that reach clinically relevant levels. Mutations in Tet proteins that permitted a better protection from tigecycline frequently exhibited reduced activity against earlier generations of tetracyclines, except for the Tet(X) enzyme mutants, which were better at inactivating all tested tetracyclines. This is particularly worrisome because different variants of Tet(X) have recently spread to multidrug-resistant pathogens through horizontal gene transfer. Therefore, Tet(X) mutants with improved activity threaten the medical future of tetracyclines. Multidrug resistance is easily disseminated through horizontally spreading conjugative plasmids. pUUH239.2 is an example of a successful conjugative plasmid that caused the first clonal outbreak of extended spectrum β-lactamase-producing Klebsiella pneumoniae in Scandinavia. This plasmid was formed after rearrangements between two different plasmid backbones and it carries resistance genes to multiple antibiotic classes, heavy metals, and detergents.