The increase of multi-resistant bacteria highlights that the golden era of antibiotics is ending and that alternative treatmentsare urgently needed. Phages have been historically used to treat bacterial infections prior to the discovery of antibiotics and have gained renewed interest in the past decade. Despite the advantages of phage therapy over traditional antibiotic usage, a number of concerns persist over their clinical application centring on their efficacy and safety. This thesis presents four papers that focus on the isolation and characterization of phages that target reference strains and drug-resistant strains of E. coli as well as their infection dynamics and kinetics. In Paper I, six of thirty isolated phages were selected to be characterized for their growth parameters and host range using two commonly used methods. The study showed that the host range (an important selection criteria for phages) of the phages can change based on the assessment method and that the lysis efficiency of phages is host-dependent. The study suggests that standardised methods to assess the host range and lytic activity of phages are required to reduce result variability between research groups. Paper II investigated a rare phage with C3 morphotype from the Podoviridae family and characterised it via genomic, proteomic, morphologic and phylogenetic analysis. The study revealed previously unseen aspects including the formation of a honeycomb structure comprised of phage head during DNA packaging, the possible contractile nature of the tail and the 280 million year co-evolution between the major head protein and the scaffolding protein. Paper III highlights the need to take the immune system into consideration when designing phage therapeutics. In the study, four purified structurally distinct phages (selected from the three main phage families) were exposed to human cells (HT-29 and Caco-2 immortalised intestinal epithelial cell lines and donor-derived peripheral blood mononuclear cells) and the immunogenicity of the phages determined. Phage immunogenicity was shown to vary in a concentration and phage dependent manner with SU63 (a Myoviridae) being the most immunogenic phage and SU32 (a Siphoviridae) the least immunogenic. In the presence of human cells and a suitable host, phages were shown to maintain their killing efficacy as well as the ability to proliferate. Paper IV studies the infection dynamics of an experimental two-phage cocktail against a single bacterial host in vitro and in silico. However, in silico analysis and in vitro analysis produced conflicting results, in which mathematical modelling predicted the complete clearance of bacteria for all treatment scenarios whereas experimental results showed a 1-3log10 reduction in bacterial content. Practical experiments also showed increased anti-bacterial activity when the time between the additions of each phage was varied. This discrepancy suggests that the current mathematical model is unsuitable due to the inability to account for discrete variables such as interference. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p><p> </p>

Com o evento da resistência dos microrganismos aos antimicrobianos, surgiram as cepas multirresistentes de difícil tratamento, e com isso tornou-se imprescindível a adesão total dos profissionais de saúde às precauções empregadas na assistência aos portadores desses microrganismos, visando evitar a sua disseminação no ambiente hospitalar. Este estudo do tipo descritivo transversal foi realizado em uma instituição de saúde filantrópica do interior de Minas Gerais, teve como objetivos avaliar a adesão dos enfermeiros, técnicos e auxiliares de enfermagem às medidas preventivas empregadas na assistência aos portadores desses microrganismos multirresistentes. A coleta de dados ocorreu no período de outubro a novembro de 2003 e os dados foram analisados qualitativa e quantitativamente. Utilizou-se do Método de análise de conteúdo de BARDIN (1977) e para a análise quantitativa de alguns dados, empregou-se a estatística descritiva, sendo os mesmos interpretados com base no significado atribuído por ROSENSTOCK (1974a). O Modelo de Crenças em Saúde (MCS) possibilitou identificar as barreiras físicas, cognitivas e psicológicas que justificaram a não-adesão de alguns profissionais às medidas preventivas direcionadas ao portador de Bactérias Multirresistentes (BMR). Como resultado destas avaliações, identificou-se que as percepções dos profissionais de enfermagem relacionadas à severidade das doenças causadas por BMR eram adequadas, que a maioria dos profissionais entrevistados associou a gravidade das doenças causadas por BMR a tratamento difícil ou a maior índice de mortalidade, e outros associaram-nas a tratamento inexistente. Quanto à susceptibilidade da doença, o conhecimento dos profissionais a respeito da temática apresentou-se bastante limitado. Os profissionais se aperceberam como susceptíveis de contrair BMR, entretanto, somente alguns conseguiram identificar os grupos mais susceptíveis à infecção causada por BMR. Observou-se uma influência favorável da instituição ao se constatar que proporciona aos profissionais as condições necessárias para que estes empreguem o Protocolo de Isolamento Específico. O comportamento dos profissionais em relação ao uso dos Equipamentos de Proteção Individual (EPI) evidenciou controvérsias, pois muitos relataram utilizar freqüentemente os paramentos, contudo admitiram que alguns profissionais não os utilizam rigorosamente por diversos motivos, sendo mais freqüentes: a crença de que não vão contrair a doença, diagnóstico tardio, ou por resistência, ou seja, injustificadamente “ ... não usa porque não quer ...". Observou-se que muitos profissionais não aderem totalmente às precauções por opção pessoal, eles não têm o hábito de lavar as mãos ou friccioná-las com álcool na freqüência que deveriam, apesar de terem os materiais disponíveis. Acreditam que os benefícios à adesão são: proteção, prevenção de adquirir infecção/doenças, o fato de evitar a disseminação e sua segurança. Quanto às barreiras, mencionaram principalmente a falta de vagas, o diagnóstico tardio e a falta de alguns materiais. O estímulo para a ação, referido preferencialmente pelos profissionais, foi a abordagem informal na prática diária. Identificaram-se, ainda, a necessidade de elaborar estratégias de intervenção capazes de aprimorar a conduta dos profissionais de enfermagem e o levantamento dos problemas considerados imprescindíveis para percepção das crenças dos profissionais, a fim de se implementar efetivamente as estratégias que devem alterar positivamente a situação observada. / As microorganisms acquired resistance against antimicrobial agents, multiresistant strains appeared which are difficult to treat. Hence, the total adhesion of health professionals to the precaution measures used in care for patients with multiresistant microorganisms has become essential, with a view to avoiding their dissemination in the hospital environment. This descriptive transverse study was carried out at a philanthropic health institution in the interior of Minas Gerais, Brazil and aimed to evaluate the adhesion of nurses, nursing technicians and auxiliaries to prevention measures used in care for patients with these multiresistant microorganisms. Data were collected in October and November 2003 and were subject to qualitative and quantitative analysis. BARDIN’s (1977) content analysis method was used. Descriptive statistics was used with a view to the quantitative analysis of some data, which were interpreted on the basis of the meaning attributed by ROSENSTOCK (1974a). The Health Belief Model (HBM) allowed us to identify the physical, cognitive and psychological obstacles that justify some professionals’ non-adhesion to the prevention measures oriented towards patients with Multiresistant Bacteria (MRB). As a result of these evaluations, it was identified that nursing professionals adequately perceived the seriousness of diseases caused by MRB, that most of the interviewees linked up the gravity of diseases caused by MRB with difficult treatment or higher mortality rates, while others associated it with the inexistence of treatment. With respect to disease susceptibility, professionals demonstrated a rather limited knowledge about the theme. They perceived themselves as susceptible to MRB, although only some professionals managed to identify the groups that are most susceptible to infection by MRB. A favorable institutional influence was observed when verifying that the institution provides its professionals with the necessary conditions to use the Specific Isolation Protocol. Professional behavior in relation to Individual Protection Equipment (IPE) usage revealed controversies, since many of them mentioned frequent usage, although they admitted that some professionals do not use this equipment in a strict way, for different reasons, among which the most frequent were: the belief that they will not contract the disease, late diagnosis, or due to resistance, that is, without any justification “ ... they do not use it because they do not want to ...". It was observed that many professionals choose not to adhere totally to the precaution measures. They are not used to washing their hands or scrubbing them with alcohol as frequently as they should, although the material is available. They believe that benefits of adhesion are: protection, prevention of infection/diseases, avoiding dissemination and their safety. With respect to obstacles, they mainly mentioned the lack of beds, late diagnosis and the lack of some kinds of material. As a stimulus towards action, professionals prefer the informal approach in daily practice. We also identified the need to elaborate intervention strategies capable of improving nursing professionals’ behavior and surveyed the problems considered essential to perceive professional beliefs, with a view to the efficient implementation of strategies that should positively change this situation.

Com o evento da resistência dos microrganismos aos antimicrobianos, surgiram as cepas multirresistentes de difícil tratamento, e com isso tornou-se imprescindível a adesão total dos profissionais de saúde às precauções empregadas na assistência aos portadores desses microrganismos, visando evitar a sua disseminação no ambiente hospitalar. Este estudo do tipo descritivo transversal foi realizado em uma instituição de saúde filantrópica do interior de Minas Gerais, teve como objetivos avaliar a adesão dos enfermeiros, técnicos e auxiliares de enfermagem às medidas preventivas empregadas na assistência aos portadores desses microrganismos multirresistentes. A coleta de dados ocorreu no período de outubro a novembro de 2003 e os dados foram analisados qualitativa e quantitativamente. Utilizou-se do Método de análise de conteúdo de BARDIN (1977) e para a análise quantitativa de alguns dados, empregou-se a estatística descritiva, sendo os mesmos interpretados com base no significado atribuído por ROSENSTOCK (1974a). O Modelo de Crenças em Saúde (MCS) possibilitou identificar as barreiras físicas, cognitivas e psicológicas que justificaram a não-adesão de alguns profissionais às medidas preventivas direcionadas ao portador de Bactérias Multirresistentes (BMR). Como resultado destas avaliações, identificou-se que as percepções dos profissionais de enfermagem relacionadas à severidade das doenças causadas por BMR eram adequadas, que a maioria dos profissionais entrevistados associou a gravidade das doenças causadas por BMR a tratamento difícil ou a maior índice de mortalidade, e outros associaram-nas a tratamento inexistente. Quanto à susceptibilidade da doença, o conhecimento dos profissionais a respeito da temática apresentou-se bastante limitado. Os profissionais se aperceberam como susceptíveis de contrair BMR, entretanto, somente alguns conseguiram identificar os grupos mais susceptíveis à infecção causada por BMR. Observou-se uma influência favorável da instituição ao se constatar que proporciona aos profissionais as condições necessárias para que estes empreguem o Protocolo de Isolamento Específico. O comportamento dos profissionais em relação ao uso dos Equipamentos de Proteção Individual (EPI) evidenciou controvérsias, pois muitos relataram utilizar freqüentemente os paramentos, contudo admitiram que alguns profissionais não os utilizam rigorosamente por diversos motivos, sendo mais freqüentes: a crença de que não vão contrair a doença, diagnóstico tardio, ou por resistência, ou seja, injustificadamente “ ... não usa porque não quer ...”. Observou-se que muitos profissionais não aderem totalmente às precauções por opção pessoal, eles não têm o hábito de lavar as mãos ou friccioná-las com álcool na freqüência que deveriam, apesar de terem os materiais disponíveis. Acreditam que os benefícios à adesão são: proteção, prevenção de adquirir infecção/doenças, o fato de evitar a disseminação e sua segurança. Quanto às barreiras, mencionaram principalmente a falta de vagas, o diagnóstico tardio e a falta de alguns materiais. O estímulo para a ação, referido preferencialmente pelos profissionais, foi a abordagem informal na prática diária. Identificaram-se, ainda, a necessidade de elaborar estratégias de intervenção capazes de aprimorar a conduta dos profissionais de enfermagem e o levantamento dos problemas considerados imprescindíveis para percepção das crenças dos profissionais, a fim de se implementar efetivamente as estratégias que devem alterar positivamente a situação observada. / As microorganisms acquired resistance against antimicrobial agents, multiresistant strains appeared which are difficult to treat. Hence, the total adhesion of health professionals to the precaution measures used in care for patients with multiresistant microorganisms has become essential, with a view to avoiding their dissemination in the hospital environment. This descriptive transverse study was carried out at a philanthropic health institution in the interior of Minas Gerais, Brazil and aimed to evaluate the adhesion of nurses, nursing technicians and auxiliaries to prevention measures used in care for patients with these multiresistant microorganisms. Data were collected in October and November 2003 and were subject to qualitative and quantitative analysis. BARDIN’s (1977) content analysis method was used. Descriptive statistics was used with a view to the quantitative analysis of some data, which were interpreted on the basis of the meaning attributed by ROSENSTOCK (1974a). The Health Belief Model (HBM) allowed us to identify the physical, cognitive and psychological obstacles that justify some professionals’ non-adhesion to the prevention measures oriented towards patients with Multiresistant Bacteria (MRB). As a result of these evaluations, it was identified that nursing professionals adequately perceived the seriousness of diseases caused by MRB, that most of the interviewees linked up the gravity of diseases caused by MRB with difficult treatment or higher mortality rates, while others associated it with the inexistence of treatment. With respect to disease susceptibility, professionals demonstrated a rather limited knowledge about the theme. They perceived themselves as susceptible to MRB, although only some professionals managed to identify the groups that are most susceptible to infection by MRB. A favorable institutional influence was observed when verifying that the institution provides its professionals with the necessary conditions to use the Specific Isolation Protocol. Professional behavior in relation to Individual Protection Equipment (IPE) usage revealed controversies, since many of them mentioned frequent usage, although they admitted that some professionals do not use this equipment in a strict way, for different reasons, among which the most frequent were: the belief that they will not contract the disease, late diagnosis, or due to resistance, that is, without any justification “ ... they do not use it because they do not want to ...”. It was observed that many professionals choose not to adhere totally to the precaution measures. They are not used to washing their hands or scrubbing them with alcohol as frequently as they should, although the material is available. They believe that benefits of adhesion are: protection, prevention of infection/diseases, avoiding dissemination and their safety. With respect to obstacles, they mainly mentioned the lack of beds, late diagnosis and the lack of some kinds of material. As a stimulus towards action, professionals prefer the informal approach in daily practice. We also identified the need to elaborate intervention strategies capable of improving nursing professionals’ behavior and surveyed the problems considered essential to perceive professional beliefs, with a view to the efficient implementation of strategies that should positively change this situation.

A multirresistência aos antibióticos observada em bacilos gram-negativos é um grave problema de saúde pública devido a alta morbidade e mortalidade apresentada, especialmente em instituições assistenciais de saúde. Como consequência do intenso uso de antibióticos, a multirresistência a esses fármacos é principalmente mediada por enzimas hidrolisantes, onde destaca-se as enzimas ?-lactamases, principal mecanismo de resistência aos ?-lactâmicos verificado em bacilos gram-negativos. Os esgotos de origem hospitalar e de estações de tratamento de esgoto (ETE) são considerados como reservatórios de bactérias multirresistentes pela presença de antibióticos que as selecionam e por favorecem a transmissão de determinantes de resistência. Nesse sentido, o presente estudo objetivou avaliar a multirresistência a antibióticos e a produção de enzimas ?-lactamases em bacilos gram-negativos isolados de efluente hospitalar e da estação de tratamento de esgoto, na cidade de Ribeirão Preto, SP. No hospital terciário, amostras de esgotos foram coletadas dos ambulatórios, das enfermarias e da junção do esgoto hospitalar. Na ETE, amostras foram coletadas na caixa de entrada do esgoto bruto e após ao tratamento. Dez microlitros foram semeados em ágar MacConkey, SalmonellaShigella, Cetrimide e TCBS e a identificação dos bacilos gram-negativos foi realizada pelo kit Bactray®. O teste de susceptibilidade aos antibióticos foi realizado pelo método de discodifusão em ágar. A detecção fenotípica de bacilos produtores de ESBL foi realizada pelos testes de sinergia de disco-duplo e disco combinado com ácido clavulânico, e para detecção de isolados produtores de carbapenemases foi utilizado os testes de disco combinado com ácido fenilborônico e EDTA e o teste Blue Carba. A PCR foi utilizada para amplificação dos genes codificadores de ESBL e carbapenemases. No total, 45 bacilos gram-negativos foram isolados, sendo as espécies Klebsiella pneumoniae e Pseudomonas aeruginosa as de maiores prevalências. Ampla resistência foi verificada aos antibióticos ?-lactâmicos, sendo a resistência ao aztreonam, a cefepime e a cefotaxima mais expressiva nos isolados do esgoto hospitalar, com diferenças estatisticamente significante (p<0,05). O fenótipo multidroga resistente foi atribuído a 33,3%, nos isolados exclusivamente do esgoto hospitalar, com diferença estatisticamente significante (p = 0,0025) em relação aos isolados do esgoto da ETE. Genes de ?-lactamases foram encontrados em 35,6% das bactérias, sendo o blaKPC e blaTEM os de maiores ocorrências, ambos em 17,8% dos isolados, e os genes blaSHV e blaCTX-M em 13,3% e 8,9%. Somente em um isolado de Enterobacter cloacae no esgoto tratado da ETE foi identificado o gene blaSHV, os demais isolados portadores dos genes de ?-lactamases foram encontrados no esgoto hospitalar. Os dados obtidos neste estudo são importantes levando em consideração que no Brasil o esgoto hospitalar pode ser lançado in natura na rede coletora municipal, no entanto, acredita-se que tal permissão favorece a disseminação da multirresistência bacteriana, posto que, os resultados demonstram alta frequência de bactérias portadoras de genes de resistência a antibióticos no esgoto hospitalar estudado. Assim, a implementação do tratamento de efluentes hospitalares, especialmente os de hospitais terciários, e adicionalmente ao tratamento da ETE evitaria a propagação dessas bactérias no ambiente e de impactar negativamente os recursos hídricos / Antibiotic multi-resistance observed in Gram-negative bacilli is a serious public health problem due to high morbidity and mortality, especially in health care institutions. As a consequence of the intense use of antibiotics, multi-resistance to these drugs is mainly mediated by hydrolyzing enzymes, in which ?-lactamases, the main ?-lactam resistance mechanism observed in Gramnegative bacilli, are prominent. Hospital sewage and wastewater treatment plants (WWTP) are considered reservoirs of multiresistant bacteria by the presence of antibiotics that select these bacteria and favor the transmission of resistance determinants. In this sense, the present study aimed to evaluate the antibiotics multi-resistance and the production of ?-lactamase enzymes in Gram-negative bacilli isolated from hospital effluent and the wastewater treatment plants in Ribeirão Preto city, SP. In the tertiary hospital, sewage samples from the outpatient clinics, rooms patients and the hospital sewage junction were collected. In the WWTP, raw and treated sewage were collected. Ten microliters were seeded on MacConkey, Salmonella-Shigella, Cetrimide and TCBS agar and the identification of Gram-negative bacilli was performed by the Bactray® kit. Antibiotic susceptibility test was performed by agar-diffusion method. Phenotypic detection of ESBL-producing bacilli was performed by double-disc and discsynergy tests combined with clavulanic acid, and for the detection of carbapenemase-producing isolates the combined disk tests with phenylboronic acid and EDTA and Blue Carba test were used. PCR amplification of ESBL and carbapenemases-encoding genes was used. In total, 45 Gram-negative bacilli were isolated, and Klebsiella pneumoniae and Pseudomonas aeruginosa being the most prevalent. Extensive resistance was verified to ?-lactam antibiotics and resistance to aztreonam, cefepime and cefotaxime was more pronounced in hospital sewage isolates, with statistically significant differences (p<0.05). Multidrug-resistant phenotype was attributed to 33.3% in isolates exclusively from hospital sewage, with a statistically significant difference (p = 0.0025) in relation to the sewage isolates from the WWTP. ?-lactamase genes were found in 35.6% of the bacteria, with blaKPC and blaTEM having the highest occurrences, both in 17.8% of the isolates, and the blaSHV and blaCTX-M genes in 13.3% and 8, 9%. Only in an isolate of Enterobacter cloacae in the treated sewage from WWTP was the blaSHV gene identified, the other isolates carrying the ?-lactamases genes were found in hospital sewage. The data obtained in this study are important considering that in Brazil the hospital sewage can be released in nature in municipal collection network, however, it is believed that such permission favors the dissemination of bacterial multi-resistance, since, the results show high frequency of bacteria carrying antibiotic resistance genes in the hospital sewer studied. Thus, the implementation of treatment of hospital effluents, especially those in tertiary hospitals, and in addition to the treatment of WWTP would prevent the spread of these bacteria in the environment and negatively impact water resources

Pseudomonas aeruginosa é um patógeno oportunista que ocasiona diferentes infecções em humanos. O surgimento de linhagens multirresistentes (MRs), contra os antibióticos comercialmente disponíveis, tem causado elevados níveis de morbidade e mortalidade. O objetivo deste estudo foi identificar uma molécula de piocina que apresente potente atividade bactericida contra cepas de P. aeruginosa MRs. Uma piocina de baixo peso molecular, produzida pela cepa ET02, apresentou potente atividade bactericida contra treze linhagens de P. aeruginosa produtoras de -lactamases (SPM-1, GIM-1, VIM-1, IMP-1, KPC-2, OXA-18 e GES-5). Essa piocina foi purificada e identificada como S8 através de espectrometria de massas e sequenciamento de DNA. Os genes codificadores da piocina S8 estão presentes no interior de um transposon localizado no cromossomo bacteriano da cepa ET02. Estes resultados demonstram que S8 possui potente atividade bactericida contra linhagens de P. aeruginosa MRs, podendo vir a ser utilizada como um composto antimicrobiano no tratamento de infecções hospitalares. / Pseudomonas aeruginosa is an opportunist pathogen that causes human infections. The emergence of multidrug resistant strains (MRs) against antibiotics commercially available has been causing elevated mortality and morbidity levels. The purpose of this study was to identify a molecule of pyocin with a potent bactericidal activity against P. aeruginosa MRs strains. A low molecular weight pyocin, produced by ET02 strain, has presented wide bactericidal activity against thirteen lineages of P. aeruginosa, producers of -lactamases (SPM-1, GIM-1, VIM-1, IMP-1, KPC-2, OXA-18 e GES-5). This pyocin was purified and identified as S8 through mass spectrometry and DNA sequencing. The pyocin S8 encoding genes are present in the interior of a transposon located in the bacterial chromosome of the ET02 strain. These results demonstrate that S8 have potent bactericidal activity against P. aeruginosa MRs lineages, and may well be used as an antimicrobial compound on treatment of hospital infections.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / In recent years, the isolation of bacteria producing β-lactamases has caused concern around the world, due to the fact these enzymes hydrolysis the ring β-lactam antimicrobials used in the main clinic. This aim of this study was asses the prevalence metallo-β-lactamases (MbL) in isolates of Pseudomonas aeruginosa and Acinetobacter baumannii obtained from patients admitted at the University Hospital of Santa Maria (HUSM). The profile of susceptibility for all isolates was evaluated by the disk diffusion method standardized by CLSI. The antimicrobial disks were distributed in a way that allows the identification of strains producers of AmpC and ESBL. For the identification of the producers of MbL the test of disk approximation with EDTA 0.1 M, EDTA 0,5M and acid 2-mercaptopropionic were performed. Isolates that did not have any of the mechanisms of resistance search were classified as multiresistant (MDR). The minimum inhibitory concentration (MIC) for ceftazidima, imipenem and polymyxin B was assessed by broth method microdilution for all isolated, according to CLSI. From January to June 2006, were obtained 32 isolates the P.aeruginosa and 41 the A. baumannii, the those 17 (23.29%) were β-lactamase AmpC-type producers, 11 (15.07%) were MbL producers, and 45 (61,64%) were classified as MDR. All strains producing MbL were Pseudomonas aeruginosa. The sensitivity of the isolates according to the CIM for antimicrobial evaluated were: 90,28% for polymyxin B, 36,11% for imipenem and 18% for ceftazidima. There was a high prevalence of MDR isolates and producers of β-lactamase-type AmpC and MbL in HUSM, this is extremely worrying once there is limiting therapy available. This situation becomes even more worrying with the find of isolates resistant the polymyxin B, witch is one of the last options of treatment for MDR isolates and producers of MbL. The detection of microorganisms is extremely important for the committees of infection hospital with the goal of preventing outbreaks, as well as guide the medical team on the conduct therapy, since there are few effective antimicrobial clinically for these pathogens and no prospects for development the new antimicrobial in the near future. / Nos últimos anos, o isolamento de bactérias produtoras de β-lactamases tem causado preocupação em todo o mundo, devido ao fato dessas enzimas hidrolisarem o anel β- lactâmico dos principais antimicrobianos utilizados na clínica. Este trabalho teve por objetivo avaliar a prevalência de metalo-β-lactamases (MbL) em isolados de Pseudomonas aeruginosa e Acinetobacter baumannii obtidos de pacientes atendidos no Hospital Universitário de Santa Maria (HUSM). O perfil de sensibilidade para todos os isolados foi avaliado pelo método de disco difusão padronizado pelo CLSI. Os discos de antimicrobianos utilizados foram distribuídos de forma que permitisse a identificação dos isolados produtores de AmpC e ESBL. Para a identificação dos produtores de MbL utilizou-se o teste de disco aproximação com os seguintes agentes quelantes: EDTA 0,1M, EDTA 0,5 M e ácido 2-mercaptopropiônico. Os isolados que não possuíam nenhum dos mecanismos de resistência pesquisados foram classificados como multirresistentes (MDR). A concentração inibitória mínima (CIM) para ceftazidima, imipenem e polimixina B foi avaliada pelo método de microdiluição em caldo para todos os isolados, de acordo com o CLSI. Durante o período de janeiro a junho de 2006 foram obtidos 32 isolados de P.aeruginosa e 41 de A. baumannii, destes 17 (23,29%) foram produtores de β-lactamase do tipo AmpC, 11 (15,07%) foram produtores de MbL e 45 (61,64%) foram classificados como MDR. Todas as cepas produtoras de MbL foram de Pseudomonas aeruginosa. A sensibilidade dos isolados de acordo com a CIM para os antimicrobianos avaliados foram as seguintes: 90,28% para polimixina B, 36,11% imipenem e 18% ceftazidima. Observou-se uma alta prevalência de isolados MDR no HUSM, além de isolados produtores de β-lactamase do tipo AmpC e MbL, o que é extremamente preocupante devido limitar a terapia a poucos antimicrobianos. Esta situação torna-se ainda mais preocupante com a detecção de isolados resistentes a polimixina B, a qual é uma das últimas opções de tratamento para infecções causadas por isolados de P. aeruginosa e Acinetobacter baumannii MDR e produtores de MbL. A detecção desses microrganismos é de grande importância para as comissões de controle de infecção hospitalar com o objetivo de prevenir surtos, bem como orientar a equipe médica sobre a conduta terapêutica, uma vez que há poucos antimicrobianos efetivos clinicamente para esses patógenos e as perspectivas para o desenvolvimento de novos antimicrobianos em um futuro próximo são mínimas.

La résistance aux antibiotiques demeure un problème majeur de santé publique particulièrement dans les pays en voie de développement (PVD) où les conditions d’hygiène sont encore précaires et où l’utilisation des antibiotiques est souvent abusive et très peu contrôlée. Cette thèse a pour objectif principal d’étudier la prévalence, la circulation et la caractérisation génétique des bactéries multirésistantes (BMR) dans un PVD, le Burkina Faso. Ce travail permet de mieux comprendre la propagation de ces BMR dans ce pays et de donner des informations indispensables pour les services de santé publique. Dans cette région, c’est la première étude du genre et cette thèse représente donc un travail original et informatif. A partir d’une revue de la littérature réalisée sur la problématique de l’émergence des BMR en Afrique de l’ouest, les objectifs spécifiques sont : i) d’étudier la prévalence et la caractérisation phénotypique et génotypique des bêta-lactamases à spectre élargi (BLSE) chez les entérobactéries isolées en portage et dans les processus infectieux ; ii) d’évaluer la sensibilité des entérobactéries aux carbapénèmes ; iii) de documenter la prévalence du portage nasal de Staphylococcus aureus (SAUR) résistant à la méticilline (SARM) ainsi que d’effectuer la caractérisation moléculaire les isolats de SAUR. Les isolats ont été prélevés par les services de santé publique au sein des 3 CHU du Burkina et ont été remis en culture au laboratoire de bactériologie du CHU de Montpellier [un total de 594 souches, 522 entérobactéries (214 en portage et 308 dans les processus infectieux) et 72 SAUR]. L’identification des espèces bactériennes repose sur la spectrométrie de masse MALDI-TOF. L’évaluation de la sensibilité aux antibiotiques s’appuie sur la méthode de diffusion en milieu gélosé. Les BLSE et les carbapénémases chez les entérobactéries sont identifiées par méthodes moléculaires (PCR et séquençage) et la caractérisation génétique des isolats de SAUR par une technique de puce à ADN. Au Burkina Faso, les points importants sont : des taux très élevés en portage et dans les infections d’entérobactéries sécrétrices de BLSE en hospitalier et en communautaire; les antécédents de consommation d’antibiotiques ou d’hospitalisation sont des facteurs de risque de portage ; par les isolats BLSE, Escherichia coli est l’espèce prédominante ; la majorité des BLSE sont des CTX-M-15, suivi de CTX-M-14, 27 et SHV-12 ; l’étude des phylogroupes d’E. coli suggère une expansion des gènes CTX-M-15 d’origine plasmidique et non liée à une épidémie de clone ; des isolats d’E. coli producteurs de carbapénémase OXA-181 avec un support génétique plasmidique de type IncX3 sont identifiés. On observe un taux de portage nasal de SAUR classique avec une très faible prévalence de SARM ; on note dans une forte proportion des gènes de virulence (Leucocidine de Panton Valentin et du facteur EDIN) parmi les SAUR en portage constituant des facteurs de risques de gravité lors des infections ; l’analyse génétique des isolats de SAUR montre une grande diversité de clones. Les études de prévalence et de génétiques apportent des informations fondamentales pour l’épidémiologie des BMR, base indispensable pour appréhender la lutte et le contrôle de ces organismes pathogènes résistants. En conclusion, ces premières études réalisées au Burkina permettent de définir les perspectives de recherche et les stratégies à développer pour le contrôle l’émergence et la diffusion de ces BMR. / Antibiotic resistance is a major public health issue, particularly in developing countries where health conditions are still inadequate and antibiotic use is often unjustified and not properly regulated. The main objective of this thesis was to study the prevalence, spread and genetic features of multi-resistant bacteria (MRB) in Burkina Faso, a developing country. This work allows better understanding MRB spread in this country and gives essential information for the development of public health policies. This is the first study in this region and this thesis is therefore an original and informative work. Starting from a review of the literature data on the issue of MRB emergence in West Africa, the specific objectives are: i) to study the prevalence and to characterize phenotypically and genotypically the extended-spectrum beta lactamases (ESBL) in enterobacterial samples isolated from healthy carriers and during the clinical phase of infection; ii) to assess the sensitivity of such enterobacterial samples to carbapenem drugs; iii) to document the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and to molecularly characterize all S. aureus isolates. Samples were collected by the public health services of three Burkina Faso University Hospital Centers (UHC) and were then cultured at the Laboratory of Bacteriology of Montpellier UHC [total n= 594 isolates of which 522 were Enterobacteriaceae isolates (214 from healthy carriers and 308 from patients with clinical infection) and 72 S. aureus isolates]. Bacterial species were identified by MALDI-TOF mass spectrometry. Antibiotic sensitivity was tested using the agar diffusion method. ESBL and carbapenemases in enterobacterial isolates were identified using molecular methods (PCR amplification and sequencing). S. aureus isolates were genetically characterized by using DNA arrays. This work shows that in Burkina Faso, ESBL-producing enterobacterial strains are frequent both in healthy carriers and hospitalized patients and that previous antibiotic use or hospitalizations are risk factors for colonization. Among the ESBL-producing enterobacterial strains, Escherichia coli was the predominant species and most ESBL-producing isolates were CTX-M-15, followed by CTX-M-14, 27 and SHV-12. The analysis of the E. coli phylogenetic groups suggests a plasmid-mediated spread of CTX-M-15 genes and not linked to an epidemic clone. Moreover, E. coli strains that produce the carbapenemase OXA-181 and with an IncX3-type plasmid have been identified. Concerning S. aureus, the rate of nasal carriage was classical with a low prevalence of MRSA. Among the S. aureus nasal samples, a high proportion of virulence genes (Panton Valentin leukocidin and EDIN) was detected. This constitutes an important risk of severe disease during clinical infection. The genetic analysis of the S. aureus isolates showed great clone diversity. These data are essential for understanding MRB epidemiology in Burkina Faso and represent a base for fighting and controlling resistant pathogens. In conclusion, these first studies carried out in Burkina Faso allow defining the future research perspectives and strategies to be developed for controlling the emergence and spread of these MRB.

Bakgrund: Multiresistenta bakterier är ett globalt problem och ett hot mot folkhälsan. Smittförebyggande åtgärder som basala hygienrutiner är en central del i det preventiva arbetet mot multiresistenta bakterier. Patienter som är bärare av en multiresistent bakterie kan uppleva känslor av otrygghet och skam, därför är det av stor vikt att all hälso- och sjukvårdspersonal tillämpar en personcentrerad vård. Syfte: Att undersöka hälso- och sjukvårdspersonalens upplevelser av att vårda patienter med multiresistenta bakterier. Metod: Studien har genomförts som en litteraturöversikt baserad på 15 stycken artiklar. Artiklarna var av både kvalitativ, kvantitativ samt kombinerad kvalitativ och kvantitativ metod. Databaser som använts i sökningen är PubMed och CINAHL. Analysen resulterade i tre teman. Resultat: Resultatet presenteras under tre olika teman: Upplevelser av rädsla och osäkerhet, upplevd okunskap och behov av utbildning samt upplevelser av hinder för utförandet av infektions-preventiva åtgärder. Slutsats: Rädsla och osäkerhet hos vårdpersonalen framkom tydligt och ledde till brister i utförandet av omvårdnaden. Resultatet visade även en upplevd okunskap om multiresistenta bakterier och ett behov av utbildning efterfrågades. Kunskap genom utbildning skulle resultera i en större förståelse om multiresistenta bakterier och minska rädslan hos vårdpersonalen. / Background: Multiresistant bacteria is a global problem and a threat to public health. Infection prevention such as basic hygiene routines are a key part of preventive work against multiresistant bacteria. Patients who is a carrier of a multiresistant bacteria can experience feelings of insecurity and shame, therefore it is important that all healthcare professionals apply a person-centered care. Aim: To study the healthcare professionals' experience of caring for patients with multiresistant bacteria. Method: The study has been conducted as a literature review based on 15 articles. The articles were of both qualitative and quantitative method as well as mixed method with combined qualitative and quantitative method. Databases used in the search are PubMed and CINAHL. The analysis resulted in three themes. Result: The results are presented in three different themes: Experiences of fear and insecurity, experienced lack of knowledge and need for education and experiences of obstacles to the performance of infection prevention measures. Conclusion: Fear and insecurity in healthcare staff clearly emerged and led to shortcomings in the performance of nursing care. The result also showed an experienced ignorance of multiresistant bacteria and a need for education was requested. Knowledge through education would result in a greater understanding of multiresistant bacteria and reduce the fear among healthcare professionals ’.

Les bactéries multirésistantes (BMR) représentent un véritable problème de santé publique. Les antibiotiques conventionnels commencent à devenir inefficaces et des bactéries qu’à une époque étaient contrôlées, commencent à devenir de plus en plus pathogènes. L’utilisation des actifs dérivant des plantes comme certains composants issus des huiles essentielles ont déjà démontré une action bactérienne contre plusieurs bactéries dites résistantes. Pour l’administration de ces actifs, à nature lipophile, nous les avons encapsulés à l’intérieur des nanocapsules au cœur lipidique (NCL) grâce à une modification de la méthode d’inversion de phase développé dans le laboratoire Inserm U1066 au début des années 2000. Le but de cette thèse est de trouver une association avec des antibiotiques qui puisse s’avérer synergique contre des BMR. Nous avons obtenu une synergie sur plusieurs souches bactériennes avec un mélange avec trois actifs différents : l’eugénol, le carvacrol et le cinnamaldéhyde et la doxycycline (antibiotique bactériostatique de la famille des tetracyclines). Cette synergie a été également testée in vivo sur un modèle pneumopatique de souris avec des résultats qui semblent en concordance avec les résultats in vitro. Nous nous sommes servis des méthodes physico-chimiques comme l’angle de contact ou la mobilité électrophorétique, dans le but d’étudier les interactions entre les NCL et les bactéries. Les résultats obtenus semblent indiquer que les NCL recouvrent la surface de la bactérie et libèrent leurs actifs, néanmoins nous n’écartons pas l’hypothèse qu’une certaine quantité des NCL puisse aussi pénétrer la bactérie. / Multiresistant bacteria (MRB) present today a public health problem. Some antibiotics are ineffective and bacteria formerly controlled, begin to become more and more pathogenic. The use of drugs derived from plants as some components from essential oils have demonstrated a bactericidal effect against resistant bacteria.For the administration of these lipophilic drugs, they have been encapsulated in the core of lipidnanocapsules (LNC), formulated via the phase inversion method. This method was developed in the laboratory Inserm U1066 in the early 2000s.The aim of this thesis is to find a combination with an antibiotic that prove to be synergistic against MRB. We have found a synergistic effect with the combination of doxycycline (bacteriostatic antibiotic of the tetracycline class) and the LNC of a mixture of three aromatic components of essential oils (eugenol,carvacrol and cinnamaldehyde). This synergy was also tested in vivo in a pneumopathicmice model with interesting results which appear consistent with in vitro results.The interactions between LNC and bacteria were studied using physicochemical method as electrophoretic mobility and contact angle measurement. Obtained results suggest that LNC cover the surface of the bacteria and release the aromatic components. These results are also observed by confocal microscopy. Nevertheless, we also accept the hypothesis that, a certain amount of LNC can cross the bacteria.

Infecções microbianas podem ser causadas por bactérias, fungos, vírus, parasitas e algas. O presente estudo avaliou a atividade in vitro de formulações de lípides catiônicos contra bactérias multirresistêntes (MRs), fungos e microalgas de interesse médico humano e veterinário. A atividade biocida de bicelas de brometo de dioctadecildimetilamônio (DBB) foi avaliada contra bactérias gram-negativas produtoras de &#946;-lactamases de amplo espectro e carbapenemases mundialmente disseminadas. Para fungos (Candida albicans, Trichophyton rubrum) e microalgas (Prototheca zopfii), a atividade biocida de DBB, sem e com a associação a drogas antifúngicas (ex., miconazol, terbinafina e anfotericina B), foi avaliada determinando-se adicionalmente a atividade sinérgica. Nanodispersões catiônicas de DBB exibiram atividade bactericida, fungicida e algicida, mesmo para patógenos MRs, sendo que a sua associação com outros antimicrobianos resultou em uma atividade sinérgica que poderia favorecer a produção de formulações com potencial para aplicação clínica humana e veterinária. / Microbial infections can be caused by bactérias, fungi, virus, parasites and algae. This study evaluated in vitro activity from cationic lipds formulations against multiresistant bacterias (MRs), fungi and e microalgae from human and veterinary. The Biocidal activity from bromide dioctadecildimetilammonium biceles (DBB) was evaluated against gram-negative bactérias &#946;-lactamases producers and carbapenemases from broad spectrum with wide spread dissemination. For fungi (Candida albicans, Trichophyton rubrum) and microalgae (Prototheca zopfii), the biocidal activity from DBB wuth and without antifungal drugs (ex., miconazole, terbinafine e amphotericin B), was also evaluated by synergistic activity. Cationic nanodispertions of DBB has shown bactericidal, fungicidal and algicidal activity, even for MRs patogens, thus , the association with the others antimicrobials resulted in a synergistic activity wich could foment the production of the formulations with a potential application in human and veterinary medicine.