Statement of the problem: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen of increasing concern and is associated with higher hospital readmission rates, poorer prognosis, and increased mortality resulting in increasing costs to the Canadian healthcare system.1-13 Institutions have been challenged with developing effective infection control programs to prevent the spread of MRSA. The purpose of this thesis was to examine the clinical and cost-effectiveness of a universal MRSA screening intervention within a large tertiary care facility. Methods of investigation: The retrospective population-based observational study consisted of two periods. In the first period (24 months), patients admitted to the Ottawa Hospital underwent risk factor-based screening. In the second period (20 months), universal MRSA screening was implemented in which all patients were screened for MRSA upon admission. Results: The regression analysis demonstrated that the universal MRSA screening intervention was not effective in reducing the number of nosocomial MRSA cases. The economic analysis estimated that the universal MRSA screening intervention incurred an additional cost of $1.16 million/year with an estimated additional cost per patient screened of $17.76. Conclusions: The universal MRSA screening intervention was not clinically or economically effective. Further research is required to verify/dispute these findings in other settings.

Statement of the problem: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen of increasing concern and is associated with higher hospital readmission rates, poorer prognosis, and increased mortality resulting in increasing costs to the Canadian healthcare system.1-13 Institutions have been challenged with developing effective infection control programs to prevent the spread of MRSA. The purpose of this thesis was to examine the clinical and cost-effectiveness of a universal MRSA screening intervention within a large tertiary care facility. Methods of investigation: The retrospective population-based observational study consisted of two periods. In the first period (24 months), patients admitted to the Ottawa Hospital underwent risk factor-based screening. In the second period (20 months), universal MRSA screening was implemented in which all patients were screened for MRSA upon admission. Results: The regression analysis demonstrated that the universal MRSA screening intervention was not effective in reducing the number of nosocomial MRSA cases. The economic analysis estimated that the universal MRSA screening intervention incurred an additional cost of $1.16 million/year with an estimated additional cost per patient screened of $17.76. Conclusions: The universal MRSA screening intervention was not clinically or economically effective. Further research is required to verify/dispute these findings in other settings.

The Staphylococci are gram-positive bacteria that cause infections in humans and can produce severe morbidity and mortality. Methicillin resistant S. aureus (MRSA) isolates are resistant to all beta-lactam antibiotics, such as methicillin, and cephalosporins making treatment of these infections more difficult. MRSA has become prevalent throughout the United States, spreading in the health care setting and the community.The purpose of this study is to examine methicillin resistance among S. aureus isolates in an outpatient population in the state of Florida and asses possible associations between methicillin resistance and age group, gender, and geographic area. It is important to define methicillin resistance in a population so that clinical practice can adjust to the prevalence of resistance.The dataset used for this analysis is a record of all the S. aureus isolates tested by a large lab company in the state of Florida from January 1, 2003 to December 31, 2005. This is the first study to asses methicillin resistance with a population based dataset and not patients from hospitals. The percent of isolates that were methicillin resistant increased as year increased. This increase in the number of methicillin resistant isolates was significant for both the crude and adjusted analysis. When treated as a continuous variable and adjusted for age category, gender, and county of residence the odds ratio for year is 1.446, 95% CI: 1.410- 1.484. In 2005, 49.7% of the isolates were methicillin resistant. Methicillin resistance also varied by age category, gender, county, and region. For age group and gender the differences were not large and may not be clinically significant. However, there was substantial variation in methicillin resistance by region and county of residence.With nearly half of the S. aureus isolates being methicillin resistant, the beta-lactam antibiotics may no longer be an ideal choice for treating S. aureus infections in Florida. The percentage of MRSA isolates that were resistant to trimethoprim-sulfamethoxazole, tetracycline, gentamycin, and rifampin was low. These antibiotics may be feasible alternatives to treat outpatient S. aureus infections in Florida.

N-Thiolated beta-lactams are a new class of anti-MRSA and anti-Bacillus agents that have recently been reported by our laboratories. From previous studies performed in our laboratories, it is believed that the N-thiolated beta-lactams exert their antimicrobial activity through a unique mode of action that is completely unlike that of classical beta-lactam antibiotics. In the first chapter of this dissertation, a review of previously prepared N-thiolated beta-lactam analogues and their mode of action is presented. In the second chapter, the synthesis of seven different C3-oxygenated derivatives is described. These analogues were tested for antibacterial activity against Staphylococcus aureus, nine different strains of MRSA, and seven different species of Bacillus. The results of the antibacterial testing will be discussed in relation to the differences in the structures of the analogues. In chapter 3, the design and synthesis of two new, functionalized caprolactone monomers are presented. FTSThese monomers were subsequently cooligomerized with epsilon-caprolactone, as described in chapter 4. N-thiolated beta-lactams were attached to the functionalized oligomers. These antibiotic containing oligomers were then screened for activity against MSSA, MRSA, and Bacillus. The results of these biological tests and their implications for future experiments are discussed.

Bakgrund: Vårdrelaterade infektioner som Methicillin Resistent Staphylococcus Aureus, MRSA, ökar. Bakterien är komplicerad att avlägsna och idag är MRSA ett av de största vårdhygieniska problemen internationellt. Vid vård av personer som bär på MRSA krävs särskilda rutiner, såsom isoleringsvård och skyddskläder. Syfte: Att belysa personers upplevelser av att bära på MRSA i en vårdkontext. Metod: En litteraturstudie av åtta stycken kvalitativa, vetenskapliga artiklar. Materialet analyserades och sammanställdes med en beskrivande metasyntes, enligt Friberg (2012). Resultat: Tre teman tydliggjordes: ”Rutinernas inverkan på patientens upplevelse av vården”,” Patientens upplevelse av mötet med vårdpersonalen.” och ” Patientens känslomässiga upplevelse av att vara infekterad med MRSA”. Resultatet visade att MRSA infektionen ledde till starka känsloreaktioner samt att rutiner, föreskrifter och personalens förhållningssätt ofta upplevdes som negativt. Patienterna saknade förståelse för sin situation och fick inte adekvat information. Slutsats: Personer som bar på MRSA saknade information om sitt tillstånd. Det behövs ökad kunskap hos personalen för att kunna möta patienters psykiska och fysiska behov samt individanpassad patientinformation. Likaså behövs ytterligare forskning som studerar livssituationen hos MRSA bärare för att kunna lindra deras lidande

A significant challenge of the 21st century is the growing health threat stemming from drug-resistant infectious diseases. There is an undeniable need to discover new, safe and effective drugs with novel mechanisms of action to combat this threat. A study of drugs currently on the market showed that natural products account for approximately 75% of new anti-infective drugs, either as new agents or analogs based upon their structure. Unfortunately, major pharmaceutical companies have cut back tremendously in natural products research in part due to the frustrating obstacle of frequent rediscovery of compounds. Fungi in particular are difficult to work with in that they do not always produce the same variety and quantities of secondary metabolites under laboratory conditions. One of the groundbreaking discoveries evolving from genomics research is the observation that many fungi possess more gene clusters encoding for the production of secondary metabolites than the reported number of natural products isolated from those organisms. Simple epigenetic modifications such as DNA methlytransferase or histone deacetylase inhibition can activate silenced genes leading to the genesis of novel chemistry from the fungus. The work presented herein is a study of the isolation and characterization of anti-infective compounds from Floridian mangrove endophytes. In addition, epigenetic modifications were explored in order to increase the production of secondary metabolites as well as for the purpose of generating new analogs not found in the controls. Finally, structure activity relationship studies were performed in order to maximize the anti-malarial and antibiotic activity of cytosporone E.

Statement of the problem: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen of increasing concern and is associated with higher hospital readmission rates, poorer prognosis, and increased mortality resulting in increasing costs to the Canadian healthcare system.1-13 Institutions have been challenged with developing effective infection control programs to prevent the spread of MRSA. The purpose of this thesis was to examine the clinical and cost-effectiveness of a universal MRSA screening intervention within a large tertiary care facility. Methods of investigation: The retrospective population-based observational study consisted of two periods. In the first period (24 months), patients admitted to the Ottawa Hospital underwent risk factor-based screening. In the second period (20 months), universal MRSA screening was implemented in which all patients were screened for MRSA upon admission. Results: The regression analysis demonstrated that the universal MRSA screening intervention was not effective in reducing the number of nosocomial MRSA cases. The economic analysis estimated that the universal MRSA screening intervention incurred an additional cost of $1.16 million/year with an estimated additional cost per patient screened of $17.76. Conclusions: The universal MRSA screening intervention was not clinically or economically effective. Further research is required to verify/dispute these findings in other settings.

Submitted by Automação e Estatística (sst@bczm.ufrn.br) on 2018-06-15T20:07:13Z No. of bitstreams: 1 JulianaFernandesDeCarvalho_TESE.pdf: 14225582 bytes, checksum: b37aabce1fb63b496f0af0000c32473b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-06-15T22:52:44Z (GMT) No. of bitstreams: 1 JulianaFernandesDeCarvalho_TESE.pdf: 14225582 bytes, checksum: b37aabce1fb63b496f0af0000c32473b (MD5) / Made available in DSpace on 2018-06-15T22:52:44Z (GMT). No. of bitstreams: 1 JulianaFernandesDeCarvalho_TESE.pdf: 14225582 bytes, checksum: b37aabce1fb63b496f0af0000c32473b (MD5) Previous issue date: 2019-03-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq / Staphylococcus aureus são historicamente reconhecidos como importantes patógenos humanos. São bactérias esféricas e Gram positivas constituintes da microbiota normal da pele e mucosa de grande parte dos mamíferos, incluindo os seres humanos. Fatores orgânicos como imunidade do hospedeiro e integridade da barreira cutânea, bem como fatores inatos ao microrganismo como virulência, contribuem para que a condição de simbiose inicial se torne uma relação patogênica, resultando desde afecções cutâneas e subcutâneas simples até as infecções sistêmicas graves. Não obstante sua intrínseca de virulência, desde o emprego na prática clínica da Penicilina na década de 1940, estas bactérias começaram a desenvolver resistência. A ascensão de cepas de MRSA (Methicillin Resistant Staphylococcus aureus) insensíveis à múltiplos antibióticos empregados na prática clínica é um fenômeno preocupante, pois, além reduzir as opções terapêuticas contribuiu para a disseminação mundial dessa agente, ameaçando a saúde pública na medida em que aumenta a mortalidade, morbidade e custos do tratamento. Neste sentido, novas estratégias clínicas são necessárias e urgentes, e dentre elas, a vetorização de antibióticos através de campo magnético tem se mostrado uma técnica promissora. O direcionamento magnético permite, além da entrega seletiva do fármaco no local da infecção, a ampliação local de campo magnético altíssimo, alterando o microambiente bacteriano. Nesse sentido, o presente trabalho teve como objetivo estudar a ação do antibiótico, Oxacilina, vetorizado com nanopartículas magnéticas no tratamento de infecção de pele e subcutâneo de rato, provocada por Staphylococcus aureus multirresistente. As partículas magnéticas sintetizadas, ligadas ao fármaco e caracterizadas foram testadas in vivo frente à modelos de infecção com cepa MRSA CCBH 4395 (Fiocruz - RJ) e os resultados indicaram alta concentração do fármaco radiomarcado no local da infecção e revelaram redução significativa no crescimento de UFC em amostras dos animais tratados com o sistema de fármaco magnético, e mesmo daqueles tratados unicamente com o vetor magnético. Esses resultados promissores apontam, talvez, para um novo paradigma de tratamento antibiótico sem moléculas químicas, mas pela ação do campo magnético. / Staphylococcus aureus are historically recognized as important human pathogens. They are spherical and Gram positive bacteria constituting the normal microbiota of the skin and mucosa of most mammals, including humans. Organic factors such as host immunity and integrity of the skin barrier, as well as factors innate to the microorganism as virulence, contribute to the initial symbiosis condition becoming a pathogenic relationship, resulting from simple cutaneous and subcutaneous conditions to severe systemic infections. Despite its intrinsic virulence, since the use in the clinical practice of Penicillin in the 1940s, these bacteria began to develop resistance. The increase of methicillin resistant Staphylococcus aureus (MRSA) insensitive to the multiple antibiotics employed in clinical practice is a worrying phenomenon, since, in addition to reducing the therapeutic options, it has contributed to the worldwide dissemination of this agent, threatening public health as it increases mortality, morbidity and treatment costs. In this sense, new clinical strategies are necessary and urgent, and among them, the vectorization of antibiotics through magnetic field has been shown to be a promising technique. Magnetic targeting allows, in addition to the selective delivery of the drug at the site of infection, the local magnification of a very high magnetic field, altering the bacterial microenvironment. In this sense, the present study aimed to study the action of the antibiotic, Oxacillin, vectorized with magnetic nanoparticles in the treatment of skin and subcutaneous rat infections caused by multiresistant Staphylococcus aureus. The synthesized, drug bound and characterized magnetic particles were tested in vivo against models of infection with MRSA strain CCBH 4395 (Fiocruz - RJ) and the results indicated high concentration of the radiolabeled drug at the site of infection and revealed a significant reduction in the growth of CFU in samples from animals treated with the magnetic drug system, and even from those treated solely with the magnetic vector. These promising results point, perhaps, to a new paradigm of antibiotic treatment without chemical molecules, but throught the action of the magnetic field.

Introdução: Staphylococcus aureus é um patógeno que causa uma variedade de infecções nosocomiais e comunitárias. Bacteremia por Staphylococcus aureus meticilina resistente (MRSA) está associada com uma elevada morbidade e mortalidade. Alguns autores consideram uma maior taxa de mortalidade em bacteremia por MRSA em comparação aos observados em bacteremia causada por Staphylococcus aureus sensível a meticilina. O uso da vancomicina no tratamento de infecções por MRSA tem estado sobre crescente vigilância nos últimos anos, já que existe uma grande preocupação sobre a redução de sua eficácia no tratamento de pacientes com bacteremia por MRSA. Estudos sugerem que a vancomicina tem atividade reduzida contra infecções por MRSA quando os valores da concentração inibitória mínima (CIM) se aproximam do valor máximo considerável como susceptível. O locus (acessory gene regulator) regula a expressão de vários genes de virulência, de aderência e produção de biofilme, e pode estar envolvido com a diminuição da sensibilidade a vancomicina. O staphylococcal cassette chromosome (SCCmec) carreia o gene mecA que caracteriza o fenótipo clássico de MRSA e confere resistência aos antibióticos β-lactâmicos. Objetivos: Avaliar as CIMs dos antibióticos: vancomicina, por microdiluição em caldo, e daptomicina, linezolida, tigeciclina e quinopristina/dalfopristina e teicoplanina pela metodologia de Etest®; caracterizar o polimorfismo do locus agr e os tipos de SCCmec de isolados de MRSA de pacientes internados em um hospital, terciário e acadêmico, no sul do Brasil. Métodos: Estudo retrospectivo de coorte no qual foram avaliados todos os episódios de bacteremia causada por MRSA nos Centros de Terapia Intensiva (CTIs) durante o período de junho de 2009 a dezembro de 2011. A detecção dos grupos agr (agr tipo I, II, III e IV) e SCCmec (SCCmec I, II, III, IV e V) foi realizada a partir da técnica da reação em cadeia da polimerase (PCR). Resultados: Foram incluídos no total 21 pacientes. Os isolados de MRSA testados se apresentaram sensíveis a todos os antibióticos testados. O locus agr foi determinado em todos os isolados, sendo que onze pertencem ao grupo agr I (52,4%) e dez ao grupo agr II (27,6%). Já a caracterização dos tipos de SCCmec, não foi possível para onze isolados; para o restante, foi encontrado dois isolados SCCmec tipo I, cinco SCCmec tipo III e três SCCmec tipo IV. Conclusão: Apesar do pequeno número de pacientes e da necessidade de maiores estudos em nosso meio, nossos resultados sugerem que a vancomicina continua a ser a primeira opção de escolha para o tratamento de infecções por MRSA, como recomendado pela Infectious Diseases Society of America. No entanto, a publicação de uma série de estudos sugerindo a susceptibilidade reduzida à vancomicina, mesmo com CIMs próximas ou no ponte de corte, a terapia com vancomicina não seria recomendada a estes pacientes, sendo necessário a avaliação de um novo esquema terapêutico. / Background: Staphylococcus aureus is a versatile pathogen that cause a variety of nosocomial and community infections. Bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality. Some authors consider a higher rate of mortality in MRSA bacteremia compared to those observed in bacteremia caused by methicillin-sensitive Staphylococcus aureus. The use of vancomycin to treat infection due to MRSA has been under increased vigilance in recent years, since there is great concern about reducing their effectiveness in treating patients with MRSA bacteremia. Studies suggest that reduced activity against vancomycin has MRSA when the values of the minimum inhibitory concentration (MIC) approach the upper end of the range of susceptibility. The agr locus (acessory regulator gene) and regulates the expression of several virulence genes, adherence and biofilm production and can be involved in reduced sensitivity to vancomycin. The staphylococcal cassette chromosome (SCCmec) carries the mecA gene that characterizes the classic phenotype of MRSA and confers resistance to β-lactam antibiotics. Objectives: Evaluate MICs of antibiotics: vancomycin, by broth microdilution, and daptomycin, linezolid, tigecycline and quinopristina / dalfopristin and teicoplanin by Etest® methodology; characterize the polymorphism of the agr locus and SCCmec types of MRSA isolates from patients in a hospital, tertiary and academic, in southern Brazil. Methods: A retrospective cohort study which evaluated all episodes of bacteremia caused by MRSA in intensive care units (ICUs) during the period June 2009 to December 2011. The detection of agr groups (agr type I, II, III and IV) and SCCmec (SCCmec I, II, III, IV and V) were performed using the technique of polymerase chain reaction (PCR). Results: We included a total twenty one patients. The MRSA isolates tested were susceptible to all antibiotics tested. The agr locus was determined in all isolates, eleven belong to agr group I (52.4%) and ten to agr group II (27.6%). Already characterization of SCCmec types, it was not possible to eleven isolates; for the remaining two isolates found was SCCmec type I, five SCCmec type III and three SCCmec type IV. Conclusions: Despite the small number of patients and the need for further studies in this area, our results suggest that vancomycin remains the first choice option for the treatment of MRSA infections, as recommended by the Infectious Diseases Society of America. However, the publication of a series of studies suggesting reduced susceptibility to vancomycin, even with MICs near or on cut off, with vancomycin therapy would not be recommended for these patients, the evaluation of a new regimen is necessary.

Staphylococcus aureus é uma bactéria que pode ser encontrada colonizando diversas partes do corpo humano, entretanto os diversos fatores de virulência que a bactéria possui, ancorados a sua superfície ou excretados para o meio extracelular, tornam essa bactéria um potencial patógeno, causando infecções de pele e tecidos moles, osteomielite, infecções respiratórias, infecções relacionadas a cateteres e outros dispositivos e bacteremia. Um dos fatores de virulência da bactéria, é a habilidade em formar biofilmes. Biofilmes são comunidades bacterianas tridimensionais complexas, que vivem organizadas e aderidas a uma superfície biótica ou abiótica, embebidas em uma matriz exopolimérica. Cerca de 80% das bactérias vivem organizadas na forma de biofilme, pois nestas estruturas são menos sensíveis aos antibióticos e à resposta imune do hospedeiro. A habilidade de S. aureus em formar biofilme é importante pois o torna uma das principais bactérias que infecta dispositivos médicos e implantes, aumentando a morbidade e mortalidade dos pacientes que apresentam esse tipo de infecção. Os medicamentos da classe dos β-lactâmicos eram a principal escolha para o tratamento de S. aureus, entretanto nos últimos anos essa bactéria adquiriu resistência a esses antimicrobianos, através da aquisição do gene mecA, tornando escassa as opções terapêuticas. Como se não bastasse, os biofilmes bacterianos são particularmente mais resistentes a tratamentos com antibióticos, não só devido ao aumento da transmissão de mecanismos de resistência dentro da comunidade, mas também por causa das limitações de difusão da droga colocados pela matriz extracelular, inativação de antibióticos pela alta concentração de íons de metal e baixo pH, entre outros fatores. Combinados, esses atributos tornam o biofilme bacteriano em torno de 1000 vezes mais tolerante e/ou resistente aos antimicrobianos comparado às células planctônicas. A investigação de estudos epidemiológicos para prevenção dessas infecções, bom como de novas estratégias para prevenção e tratamento de infecções por biofilmes, especialmente em isolados clínicos sabidamente multirresistentes, é urgentemente necessária. Dentre estas estratégias estão a pesquisa de diferentes mecanismos ou substâncias capazes de provocar a inibição da formação ou a erradicação do biofilme formado. Neste contexto, 8 os sistemas de bombas de efluxo e inibidores de bombas de efluxo representam uma fonte promissora de erradicação do biofilme formado. O principal objetivo deste estudo é investigar características clínico-epidemiológicas em isolados clínicos que estejam associadas a formação de biofilme, bem como investigar o papel de bombas de efluxo, inibidores dessas bombas e novos genes envolvidos na habilidade de isolados clínicos de S. aureus em formar biofilme. O capítulo 1 associa características clínicas e epidemiológicas com a habilidade de formação de biofilme. O capítulo 2 mostra o papel da adição de antimicrobianos na inibição e erradicação de biofilmes, a associação com inibidores de bomba de efluxo para melhor entender os sistemas de bomba de efluxo na capacidade desses isolados em formar biofilme e por último, novos genes que participam desse processo, em isolados clínicos de MRSA. Este estudo permite planejar ações preventivas para essas infecções relacionadas a biofilmes. Além disso, demonstra que os sistemas de bombas de efluxo parecem ser alvos promissores para erradicar infecções associadas a biofilmes bacterianos. / Staphylococcus aureus can be found colonizing the human body, however its virulence factors anchored to its surface or secreted into the extracellular medium, makes this bacteria as a potential pathogenic, causing skin and soft tissue infections, osteomyelitis, respiratory infections, catheter-related and other devices infections and bacteremia. One of the virulence factors that bacteria produce is the ability to form biofilms. Biofilms are complex three-dimensional bacterial communities, living organized and attached on a biotic or abiotic surface, embedded in a matrix exopolimérica. About 80% of live bacteria are organized in the form of biofilms because in these structures are less sensitive to antibiotic and the host immune response. The ability of S. aureus to form biofilms is important because it makes it one of the main bacteria that infects medical devices and implants, increasing patient morbidity and mortality. The class of β-lactam drugs used to be main choice for the treatment of S. aureus infections, however in recent years the bacteria acquired resistance to these antibiotics by acquiring mecA gene, so therapeutic options becoming scarce. Besides that, bacterial biofilms are particularly resistant to antibiotic treatments, not only due to increased transmission resistance mechanisms within the community, but also because limitations in drug diffusion by extracellular matrix, inactivation of antibiotics due to high concentration of metal ions and low pH, and other factors. Combined, these attributes make the bacterial biofilm around 1000 times more tolerant and / or resistant to antimicrobial compared to planktonic cells. Investigation of epidemiological studies to prevent such infections, as well as new strategies for prevention and treatment of biofilm infections, especially in known multidrug-resistant clinical isolates, is urgently needed. Among these strategies we could list the different search engines or substances capable of causing or inhibiting the formation of biofilm eradication. In this context, system efflux pumps and efflux pump inhibitors represent a promising source of biofilm eradication. The aim of this study is to investigate the clinical and epidemiological characteristics in clinical isolates that are associated with biofilm formation and investigate the role of efflux pumps and inhibitors of these pumps in the ability of S. 10 aureus clinical isoltes to form biofilms. The chapter 1 associates clinical and epidemiological characteristics with biofilm formation ability. Chapter 2 shows the role of the addition of antimicrobials in inhibition and eradication of biofilms, the association with efflux pump inhibitors to better understand the efflux pump systems in the ability of these isolates to form biofilm and, finally, new genes important in MRSA clincal isolates biofilm formation. This study allows planning preventive actions for these biofilm-related infections. In addition, it demonstrates that efflux pump systems appear to be promising targets for eradicating infections associated with bacterial biofilms.