Made available in DSpace on 2014-06-11T19:27:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-06-18Bitstream added on 2014-06-13T19:35:18Z : No. of bitstreams: 1 casella_t_me_sjrp.pdf: 770175 bytes, checksum: f7648712bfc8fa3decfd5d296852e540 (MD5) / A ampla utilização de drogas antimicrobianas tem resultado em aumento e disseminação da resistência aos antimicrobianos entre bactérias patogênicas para o homem. Além do uso indiscriminado em humanos, estas drogas também são extensivamente utilizadas em medicina veterinária e no manejo de animais para a produção de alimentos, o que é reconhecido como um fator associado ao desenvolvimento da resistência em bactérias patogênicas ou comensais de animais. Evidências microbiológicas e clínicas reforçam a associação entre o uso de antimicrobianos na produção animal e o aumento da prevalência de bactérias resistentes na população humana. Sendo assim, a regulamentação da utilização de antimicrobianos no manejo de animais de produção e na terapêutica veterinária é de grande interesse para o Brasil, pois envolve além de importantes aspectos de saúde pública, questões comerciais, pois o país é um dos maiores exportadores de carnes do mundo. Neste estudo, foram analisadas amostras de carnes bovina, suína e de frango, visando à detecção de Salmonella e Escherichia coli produtoras de β-lactamases de espectro estendido (ESBLs). Os isolados bacterianos, obtidos de novembro de 2010 a agosto de 2011, foram submetidos ao teste de suscetibilidade aos antimicrobianos, e 34 cepas foram submetidas à PCR para detecção dos genes blaCTX-M, blaGES, blaSHV e blaTEM. A presença de genes de ESBLs foi confirmada em seis isolados, sendo blaCTX-M-2 detectado em uma cepa de Proteus mirabilis, uma Klebsiella pneumoniae, uma Citrobacter diversus e duas E. coli. O gene blaSHV-2 foi detectado em uma cepa de K. pneumoniae. A caracterização do ambiente genético de blaCTX-M-2 indicou a presença de integrons de classe 1 em todas as cepas, exceto C. diversus. Todos os blaCTX-M-2 foram detectados em cepas... / The wide use of antimicrobial drug has resulted in increase and spread of antimicrobial resistance among pathogenic bacteria for humans. In addition, these drugs are extensively used in veterinary and agriculture for food production, which is recognized as a factor associated with the development of resistance in pathogenic or commensal bacteria of animals. Microbiological and clinical evidence strengthen the association between use of antimicrobials in animal production and the increasing prevalence of resistant bacteria in the human population. Thus, regulation of the use of antimicrobials in the management of livestock and veterinary therapy has great interest for Brazil, because it involves, in addition to important public health issues, trade issues, as the country is one of the largest exporters of beef in the world. In this study, we analyzed samples of beef, pork and chicken meat, focusing on the detection of extended-spectrum β-lactamase (ESBLs)-producing Salmonella and Escherichia coli. The bacterial isolates, obtained from November, 2010, to August, 2011, were tested for antimicrobial susceptibility, and 34 strains were tested by PCR for detection of blaCTX-M, blaGES, blaSHV and blaTEM genes. The presence of ESBLs genes was confirmed in six isolates, being blaCTX-M-2 detected in a strain of Proteus mirabilis, one Klebsiella pneumoniae, one Citrobacter diversus and two E. coli. The blaSHV-2 gene was detected in a K. pneumoniae strain. The characterization of the genetic environment of blaCTX-M-2 indicated the presence of a class 1 integron in all strains, except C. diversus. All blaCTX-M-2 were detected in strains isolated from pork samples. The presence of other multidrug-resistant Enterobacteriaceae carrying... (Complete abstract click electronic access below)

Entre membros da Família Enterobacteriaceae a produção de β-lactamases de espectro estendido (ESBL – Extended-Spectrum β-lactamase) se constitui em um importante mecanismo de resistência a antibióticos β-lactâmicos. O objetivo deste estudo foi determinar a prevalência de ESBL em diferentes gêneros da Família Enterobacteriaceae em um hospital universitário no sul do Brasil. Além disso, avaliou-se o teste de triagem proposto pelo CLSI, o teste que utiliza discos combinados e técnica de PCR para detecção de ESBL na Família Enterobacteriaceae. De forma complementar, foi feita pesquisa de KPC em amostras com resistência (plena ou intermediária) ao ertapenem. Foram analisados 731 isolados da Família Enterobacteriaceae, obtidos a partir de amostras clínicas de pacientes hospitalizados. A prevalência de isolados produtores de ESBL na Família Enterobacteriaceae foi de 26,8% (196/731). Destacam-se Providencia spp. com uma prevalência de 91,7% (11/12), seguida de Klebsiella pneumoniae com 56,7% (59/104) e Enterobacter spp. com 40,7% (48/118). Entre os antibióticos utilizados no Teste Confirmatório Fenotípico, a cefepima foi o substrato que detectou o maior percentual dos isolados (90,6% - 183/202) como produtores de ESBL. Utilizando a técnica de PCR foi possível detectar blaTEM em 89,6% (208/232), blaSHV em 59% (137/232) e blaCTX-M em 37,9% (88/232) dos isolados. Comparando o perfil de suscetibilidade global das amostras ESBL com as demais amostras consideradas como não produtoras de ESBL, notou-se um grande decréscimo na sensibilidade de todos antimicrobianos testados (p < 0,05) nas ESBL positivas. Apenas os carbapenêmicos (Imipenem e Meropenem) apresentaram total eficácia in vitro. Outros antibióticos com maior percentual de sensibilidade para isolados produtores de ESBL foram Amicacina, Doxaciclina e Piperacilina/Tazobactam com 35,1%, 29,9% e 28,0% de sensibilidade, respectivamente. Entre os microrganismos com teste de triagem para ESBL positivo, 39 apresentaram resistência (plena ou intermediária) ao ertapenem, mas em nenhuma destas amostras foi detectado o gene blaKPC por técnica de PCR.

Este estudo avaliou a ocorrência de leveduras do gênero Candida sp além dos principais microrganismos periodontopatogênicos e enterobactérias na saliva, em mucosa e no biofilme aderido à prótese total, correlacionando com aspectos clínicos e condição de higiene bucal de 90 indivíduos edêntulos e portadores de prótese total, por meio de métodos moleculares (PCR). Espécimes clínicos intrabucais foram coletados desses indivíduos após avaliação das condições sócio-econômicas e comportamentais. A microbiota bucal dos pacientes foi caracterizada por meio da obtenção de amostras de biofilme aderido às próteses totais, mucosa e saliva, as quais foram processadas, por meio de PCR. As inter-relações entre os diferentes microrganismos foram determinadas por meio dos testes de Qui-quadrado e Mann-Whitney. Verificaram-se diferenças na ocorrência de Prevotella intermedia e Enterobacteriaceae na saliva dos pacientes edêntulos, o mesmo ocorrendo com Enterobacteriaceae, Camphylobacter rectus e gênero Pseudomonas no biofilme aderido às próteses totais. As condições de higiene bucal e estado de conservação da prótese total precários favoreceram a ocorrência de leveduras do tipo Candida sp, em especial Candida albicans, em níveis estatisticamente significante nas amostras de mucosa e biofilme aderido à prótese total, tornando este dispositivo protético um potencial reservatório de leveduras e bactérias entéricas que podem ser de relevância na patogênese das infecções oportunistas. _________________________________________________________________________________________ ABSTRACT: The aim of this study was to evaluate the occurrence of major periodontopathogenic microorganisms and Enterobacteriaceae and biofilm adhered to the denture, mucosa and saliva in 90 edentulous subjects with complete dentures, using molecular methods (PCR). Clinical specimens were collected from these individuals after assessing the socio-economic circumstances and behavioral. The oral microbiota of patients was characterized by obtaining samples of the biofilm adhered to the dental prothesis and saliva, for detection of major pathogens using PCR. The possibility of inter-relationships between different microorganisms was determined using the chi-square test and Mann-Whitney test. There were differences in the occurrence of Prevotella intermedia and Enterobacteriaceae in the saliva of edentulous patients, likewise, Enterobacteriaceae, Pseudomonas, Camphylobacter rectus and the biofilm attached to denture patients. The conditions for oral hygiene and stat of preservation of prosthesis total precarious favored the occurrence of yeasts of the Candida sp, particularly Candida albicans, statistically significant levels in samples of mucosa and biofilm acceded to total prosthesis, prothetic device, making it a potential reservoir of enteric bacteria and yeasts that may be of relevance in the pathogenesis of opportunistic infections.

Cheese is a fermented product in which bacteria contribute to different flavours and textures. In order to understand the microbial processes in cheese, it is necessary to not only look at the genomic information in bacteria. The metabolome consists of a complete collection of metabolites in a biological sample. These metabolites are small molecules with a Mr &gt;1.5 kDa, including flavour compounds. During the ripening process of cheese, many microbiological and biochemical changes occur that give cheese a diversity of textures and flavours. Proteins that go through proteolysis and amino acid catabolism are of great importance in the development of flavour in cheese, regardless of variety. Even though techniques for measurements of metabolites have existed for a long time, there are some unique challenges by analysing of several metabolites in parallel in a biological sample that promotes different metabolic pathways. Metabolic fingerprinting is the most common approach used in metabolomics, which is based on statistical analysis that through algorithms presents differences between samples. The electronic nose is able to identify the sum of volatile metabolites in a food, which is unlike the gas chromatograph that identifies individual metabolites. The aim of this review is to evaluate the use of metabolomics of selected Enterobacteriaceae together with electronic nose technology in order to analyse possible patterns of volatile metabolites produced in soft cheese. By this we hope to evaluate potential application of this approach in food quality control and microbial contamination screening. The pilot study was done together with the center for AASS, Örebro University where bacteria were analysed using the electronic nose NST3320. The study showed that it is possible to discriminate between Enterobacteriaceae, Staphylococcus aureus and cheese-associated bacteria, but also between the Enterobacteriaceae species Escherichia coli, Hafnia alvei and Klebsiella neumoniae. It is important to consider the gas sensors gradually lose their ability to detect substances after continual use, in which they need to be replaced with new gas sensors. Further, data processing requires special knowledge and can be hard to handle if the expertise is lacking. We believe that there is evidence that metabolomics together with the electronic nose have future prospects in terms of quality control and microbial contamination screening.

Cheese is a fermented product in which bacteria contribute to different flavours and textures. In order to understand the microbial processes in cheese, it is necessary to not only look at the genomic information in bacteria. The metabolome consists of a complete collection of metabolites in a biological sample. These metabolites are small molecules with a Mr &gt;1.5 kDa, including flavour compounds. During the ripening process of cheese, many microbiological and biochemical changes occur that give cheese a diversity of textures and flavours. Proteins that go through proteolysis and amino acid catabolism are of great importance in the development of flavour in cheese, regardless of variety. Even though techniques for measurements of metabolites have existed for a long time, there are some unique challenges by analysing of several metabolites in parallel in a biological sample that promotes different metabolic pathways. Metabolic fingerprinting is the most common approach used in metabolomics, which is based on statistical analysis that through algorithms presents differences between samples. The electronic nose is able to identify the sum of volatile metabolites in a food, which is unlike the gas chromatograph that identifies individual metabolites. The aim of this review is to evaluate the use of metabolomics of selected Enterobacteriaceae together with electronic nose technology in order to analyse possible patterns of volatile metabolites produced in soft cheese. By this we hope to evaluate potential application of this approach in food quality control and microbial contamination screening. The pilot study was done together with the center for AASS, Örebro University where bacteria were analysed using the electronic nose NST3320. The study showed that it is possible to discriminate between Enterobacteriaceae, Staphylococcus aureus and cheese-associated bacteria, but also between the Enterobacteriaceae species Escherichia coli, Hafnia alvei and Klebsiella pneumoniae. It is important to consider the gas sensors gradually lose their ability to detect substances after continual use, in which they need to be replaced with new gas sensors. Further, data processing requires special knowledge and can be hard to handle if the expertise is lacking. We believe that there is evidence that metabolomics together with the electronic nose have future prospects in terms of quality control and microbial contamination screening.

From Introduction: It was as early as 1904 that Paul Ehrlich propounded the idea of a “magic bullet”. This “magic bullet”, or chemotherapeutic agent, as he also called it, had to meet certain requirements: (a) a high activity against pathogenic micro-organisms; (b) easy absorption by the body; (c) activity in the presence of body fluids and tissue; (d) a low degree of toxicity; (e) must not allow the development of resistant micro-organisms. The discovery of the sulphonamide, Prentosil, by Domagk in 1935 was one of the initial steps in the search for this “magic bullet”. This, together with the production and purification of the antibiotics penicillin, by Fleming, Florey and Chain in 1942 and streptomycin, by Waksman in 1943, heralded a new era in the fight against bacterial infections. The majority of modern antibacterial agents have to a large extent met the requirements of Ehrlich’s ‘magic bullet”. They have however failed to prevent the development of resistant bacterial strains. This has been particularly noticeable in the past twenty years since the sudden emergence of multiple-resistant bacteria, many of which can transfer to several drugs in one step by a process of conjugation. This phenomenon which has serious medical implications has prompted numerous studies on the origin, epidemiology, biochemistry and genetics of transferable drug resistance.

The investigations presented in this thesis form part of a systematic international effort to establish the structures of the capsules produced by the bacterial genera, Escherichia coli and Klebsiella (family enterobacteriaceae). These bacteria are of medical interest as they are opportunistic pathogens and are frequently responsible for serious infections in animals and man. Invasive strains are invariably surrounded by a structurally complex polysaccharide capsule which contributes to the organism's ability to attenuate non-specific host defence mechanisms or, in some instances, to completely prevent an immune response. A knowledge of the chemical composition and structure of the capsule is, therefore, of great value as it provides insight into the mechanisms involved in this process. The E. coli, in particular, have generated considerable interest as their capsules are more structurally diverse and cross-reactivity with other, more pathogenic bacteria has also been demonstrated. Accordingly, the structures of three previously unstudied E. coli K-antigens viz. those produced by serotypes 020:K83:H26, 020:K84:H26, and 09:K48:H9 have been established by chemical and spectroscopic means and are presented in this thesis. In addition, a reinvestigation of the structure of the capsule produced by Klebsiella K15 using a novel enzymatic approach was also undertaken and a revised structure is proposed . The E. coli K48 polysaccharide is of special interest as it was found to contain a new diacetamido trideoxy hexose hitherto unrecorded. A synthesis for this saccharide is also presented. Finally, the application of lithium dissolved in ethylenediamine for the degradation of amino sugar-containing polysaccharides was also investigated using the capsular polysaccharides produced by E. coli serotypes K38 and K84 as model compounds.

The work presented in this thesis forms part of a continuing programme concerned with the structural determination of capsular polysaccharides of some Enterobacteriaceae. Since bacteria of this family are pathogenic to Man, work in this laboratory has focused on the structural elucidation of Klebsiella and, more recently, Escherichia coli ( E. coli) capsular polysaccharides ( K-antigens ). To date, some 74 K-antigens have been distinguished serologically within the genus E. coli and the structures of approximately 70% are known. In general, the K-antigens of the E. coli are characterized by a wide variety of constituent monosaccharides arranged in repeating units. In this thesis the structural elucidation of the capsular polysaccharides of E. coli serotypes 08: KI02: H- and 08: K47: H2 is presented. A variety of chemical techniques has been employed in the structural analysis, and are discussed. The thesis also includes extensive two-dimensional n.m.r. studies on the E. coli KI02 and K47 polysaccharides, as well as on a modified KI02 polymer produced after a lithium-ethylenediamine degradation of the native polysaccharide.

The nature of this problem divides itself into two parts, that is, a study of the old sewage plants in operation through the summer of 1947 and a study of the new plant put in operation during the fall of the same year.

No description available.