Submitted by LETICIA CHAMMA LASTÓRIA (lelastoria@yahoo.com.br) on 2016-06-30T19:14:39Z No. of bitstreams: 1 MestradoCORRIGIDO - PDF.pdf: 2088587 bytes, checksum: 05ada9bd23eac2f3af4059632d527df0 (MD5) / Rejected by Ana Paula Grisoto (grisotoana@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido está sem a ficha catalográfica. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija esta informação e realize uma nova submissão contendo o arquivo correto. Agradecemos a compreensão. on 2016-07-04T12:49:01Z (GMT) / Submitted by LETICIA CHAMMA LASTÓRIA (lelastoria@yahoo.com.br) on 2016-07-06T13:41:54Z No. of bitstreams: 1 Mestrado com ficha catalográfica pdf.pdf: 2116809 bytes, checksum: 85e18d24252e4dc8707e401c57bbe62c (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-07-06T16:29:34Z (GMT) No. of bitstreams: 1 lastoria_lc_me_bot.pdf: 2116809 bytes, checksum: 85e18d24252e4dc8707e401c57bbe62c (MD5) / Made available in DSpace on 2016-07-06T16:29:34Z (GMT). No. of bitstreams: 1 lastoria_lc_me_bot.pdf: 2116809 bytes, checksum: 85e18d24252e4dc8707e401c57bbe62c (MD5) Previous issue date: 2016-02-25 / Staphylococcus aureus resistente à meticilina (Methicillin-resistant S. aureus, MRSA) é cada vez mais reconhecido como uma ameaça para pessoas vivendo com HIV/AIDS (PVHA). No entanto, a magnitude da colonização por MRSA varia entre diferentes países e regiões geográficas. Nós realizamos um estudo que teve por objetivo identificar a prevalência e os fatores de risco para colonização por S. aureus como um todo e MRSA em PVHA residindo em cidades de pequeno porte do interior do Estado de São Paulo. Isolados de MRSA foram caracterizados por Eletroforese em Gel de Campo Pulsado (Pulsed-Field Gel Electrophoresis, PFGE) e tiveram o Cassete Cromossômico Estafilocóccico (Staphylococcal Chromosome Cassete, SCC) mec tipado. Análise espacial foi realizada para identificar agregados geográficos e correlação com indicadores socioeconômicos. No primeiro momento, realizamos um estudo de prevalência pontual coletando swab nasal e de orofaringe de 368 PVHA atendidas em ambulatório de referência em Botucatu, SP. Sessenta e sete sujeitos residentes na cidade sede foram seguidos com coletas em dois outros momentos, e tiveram seus contactantes domiciliares também investigados para colonização. As taxas de prevalência de S. aureus e MRSA no primeiro levantamento foram 25,8% e 2,7%. A colonização por S. aureus foi negativamente associada com o uso de antibióticos beta-lactâmicos e drogas ilícitas. Por outro lado, fatores de risco para MRSA incluíam uso de crack e internação hospitalar recente. Inquéritos repetidos identificaram novos casos de colonização por MRSA, mas nenhum sujeito apresentou positividade em mais de uma ocasião. Quatro clusters foram identificados na PFGE, agrupando sujeitos em diferentes níveis – domicílio, cidade, região. Dos 19 isolados caracterizados, apenas um não carreava o SCCmec tipo IV. Análise espacial identificou hot spots par sujeitos colonizados com S. aureus, mas não conseguimos ligar esse padrão a indicadores sócio-econômicos. Em conclusão, nós idenficamos baixa – mas relevante – prevalência de MRSA em PVHA. Foram identificados tanto fatores de risco tradicionalmente associados a aquisição na comunidade quanto outros ligados a exposição a hospitais, de modo que as rotas predominantes de transmissão não puderam ser determinadas com base epidemiológica. / Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly recognized as a threat for people living with HIV/AIDS (PLWHA). However, the magnitude of asymptomatic MRSA colonization in that group varies among different countries and geographic regions. We conducted a study that aimed at identifying the prevalence and risk factors for both overall S. aureus and MRSA colonization among PLWHA attending in small cities from inner São Paulo State, Brazil. MRSA isolates were characterized using Pulsed-Field Gel Electrophoresis (PFGE), and submitted to typing of the Staphylococcal Chromosome Cassete (SCC)mec. Spatial analysis was performed to search for geographical clusters and correlation with socioeconomic indicators. In a first point prevalence survey, nasal and oropharyngeal swabs of 368 people were collected. Sixty-seven subjects from the main city (Botucatu) were surveyed for colonization in two other occasions, and had swabs collected from household members. The prevalence rates for S. aureus and MRSA in the first survey were 25.8% and 2.7%. The overall S. aureus colonization was negatively associated with the use of beta-lactams and of illicit drugs. On the other hand, MRSA colonized subjects were more likely to use crack and to have been admitted to a hospital during the past year. Repeated surveys found additional cases of MRSA colonization, but all subjects were positive in only one occasion. Four PFGE clusters were characterized, grouping subjects in household, city and region level. Of 19 total MRSA isolates, only one did not harbor SCCmec type IV. Spatial analysis detected hot spots of S. aureus colonized subjects from Botucatu, but that finding could not be linked to socio-economic indicators. In conclusion, we found small but relevant prevalence of MRSA among PLWHA. Community and healthcare-associated risk factors were identified, so that predominant routes of transmission could not be determined on epidemiological grounds.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O Staphylococcus aureus resistente a meticilina (MRSA) foi inicialmente descrito como um patógeno associado a infecções relacionadas à assistência em saúde; porém, um clone de MRSA, o CA-MRSA emergiu na comunidade e está atualmente incrementando nos hospitais. O objetivo desta tese foi descrever aspectos relacionados com a epidemiologia das infecções por cepas CA-MRSA no Hospital Universitário Pedro Ernesto da Universidade do Estado do Rio de Janeiro (HUPE/UERJ), avaliando especificamente fatores de risco relacionado com as infecções por CA-MRSA. Usando informações das bases de dados do laboratório de microbiologia, da farmácia e da Comissão para Controle da Infecção Hospitalar do HUPE/UERJ foi realizado um estudo retrospectivo de infecções/colonizações por cepas de S. aureus (fevereiro 2005 a Julho 2011). Foi realizado um estudo caso e controle, utilizando como casos os pacientes com infecções por cepas CA-MRSA. Na avaliação da susceptibilidade aos antimicrobianos usados em infecções graves por MRSA (vancomicina, teicoplanina, daptomicina e linezolida), foram determinadas as concentrações inibitórias mínimas (CIM) das amostras por diferentes metodologias (testes de difusão em agar, microdiluição em caldo e E-test). Nas analises das tendências temporais da apresentação dos subtipos de MRSA, usando um critério fenotípico para classificação das cepas MRSA, foi observada uma diminuição do número de cepas de MRSA multirresistente (HA-MRSA) (p<0.05). Também foi observada uma tendência ao aumento de cepas não-multirresistentes (CA-MRSA), mas sem alcançar a significância estatística (p = 0.06) igual que os S. aureus sensíveis a meticilina (MSSA) (p = 0.48). Não houve associação entre o subtipo de MRSA e a mortalidade devida à infecção por cepas MRSA. Uma idade acima de 70 anos (OR: 2.46, IC95%: 0.99 - 6.11), a presença de pneumonia adquirida no hospital (OR: 4.94, IC95%: 1.65 -14.8), a doença pulmonar obstrutiva crônica (OR: 6.09, IC95% 1.16 31.98) e a leucemia (OR: 8.2, IC95%: 1.25 54.7) foram fatores de risco associadas à mortalidade nas infecções por cepas de S. aureus. Usando curvas de Kaplan-Meier, foi observada uma tendência ao aumento da mortalidade em infecções causadas por MSSA na primeira semana, porém sem alcançar significância estatística (p = 0.07). Não foram observadas amostras MRSA com susceptibilidade intermediaria a vancomicina, linezolida, daptomicina ou teicoplanina. A dinâmica das infecções por S. aureus no HUPE/UERJ mudou durante o período de estudo, com menor número de episódios infecciosos causados por cepas de MRSA multirresistentes. Existe uma tendência ao aumento das cepas não-multirresistentes de MRSA entanto que a taxa de infecções por MSSA permaneceu estável no período do estudo. O perfil de resistência dos estafilococos não teve associação com a mortalidade / The methicillin-resistant Staphylococcus aureus (MRSA) was described initially like a health-care associated pathogen. However, an MRSA clone called community-adquired S. aureus emerged with success in the community and now has a worring increasing frequency in hospital settings. The aim of this study was to descript issues related to the epidemiology of infections due tu CA-MRSA isolates at the Pedro Ernesto Universitary Hospital (HUPE/UERJ) in Rio de Janeiro, Brazil from february 2005 to june 2011, analyzing risk factors related to these infections. Thus, using databases of the microbiology laboratory, pharmacia department and the infection control committee of the HUPE-UERJ, was realized an restrospective study of S. aureus isolates obtained from infected/colonizated patients hospitalized from February 2005 to July 2011. To evaluate risk factors related to CA-MRSA infections was conduced a case-control study, using patients with true infections due to MRSA like cases and patients with methicillin susceptible S. aureus (MSSA) like controls. To test the antimicrobial susceptibility of the antibiotics used in MRSA severe infections (Vancomycin, teicoplanin, daptomycin and linezolid), were determinated the minimal inhibitory concentration (MIC) of MRSA isolates using differents methods (disk-difusion test, microdilution in broth and E-test strips). The trend analyses of the MRSA types, using a phenotypic criteria to classificate the MRSA isolates, found a decrease in the infections due to multi-resistant MRSA isolates (HA-MRSA) in our hospital (p<0.05). Also was observed and increase in non-multi-resistant MRSA strains (CA-MRSA), but without reach statistic significancy (p = 0.06), similar to MSSA (p = 0.48). There is not association between the MRSA phenotype and the mortality due to S. aureus infection. In the multivariate analysis, were observed that an older age than 70 years (OR: 2.46, IC95%: 0.99 - 6.11), health-care pneumonia (OR: 4.94, IC95%: 1.65 -14.8), chronic obstructive pulmonary disease (OR: 6.09, IC95% 1.16 31.98) and leucaemia (OR: 8.2, IC95%: 1.25 54.7) were risk factors associated with mortality due to S. aureus infections. The Kaplan-Meier analysis, found a trend to high mortality due to MSSA infections in the first week, but without get statistic significancy (p = 0.07). We dont found any MRSA isolated with resistance or intermediary resistance to vancomycin, linezolid, daptomycin or teicoplanin. There is good correlation between both MICs determinations, with broth microdiluiton and E-Test strips metodhology. Its were concluded that the dynamic of the S. aureus infections at the HUPE/UERJ is changing, with less number of infectious episodes due to multi-resistant MRSA isolates. Moreover, there are an increasing number of infections due to non-multi-resistant MRSA isolate. The prevalence of infections due to MSSA dont have change in the time of period study. The kind of the S. aureus phenotype dont has association with all-causes-mortality

Submitted by Etelvina Domingos (etelvina.domingos@ufpe.br) on 2015-04-09T19:51:49Z No. of bitstreams: 2 DISSERTAÇÃO Fábio José dos Santos Aguiar.pdf: 859548 bytes, checksum: 26707ed652529cbd3f3d6a6142b5b0dd (MD5) license_rdf: 9 bytes, checksum: 42dd12a06de379d3ffa39b67dc9c7aff (MD5) / Made available in DSpace on 2015-04-09T19:51:49Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Fábio José dos Santos Aguiar.pdf: 859548 bytes, checksum: 26707ed652529cbd3f3d6a6142b5b0dd (MD5) license_rdf: 9 bytes, checksum: 42dd12a06de379d3ffa39b67dc9c7aff (MD5) Previous issue date: 2014 / O objetivo deste estudo foi avaliar a ação sinérgica entre o ácido úsnico extraído de Cladonia substellata Vainio e cinco agentes antimicrobianos (ciprofloxacino, gentamicina, oxacilina e penicilina) sobre dez cepas de Staphylococcus aureus com fenótipo de resistência previamente definido. Cinco destas cepas de S. aureus (ATCC 33591, AM 13, AM 18, AM 20, AM 21) apresentaram resistência a todos os agentes antimicrobianos avaliados e desta forma foram selecionadas para o estudo do sinergismo entre o ácido úsnico e os agentes antimicrobianos através do método do tabuleiro de xadrez (checkerboard method). Os critérios utilizados para avaliar a atividade sinérgica foram definidos pelo Índice da Concentração Inibitória Fracionada (FICI). Todas as cepas de S. aureus foram suscetíveis ao ácido úsnico, determinado pelo método de microdiluição. O FICI variou de 0,25 – 1,0, sugerindo uma interação sinérgica frente as cepas de S. aureus MRSA. A associação do ácido úsnico com o ciprofloxacino apresentou efeito sinérgico sobre todas as cepas S. aureus MRSA. A oxacilina apresentou sinergismo em associação com ácido úsnico sobre as cepas de S. aureus ATCC 33591, AM 13, AM18 e AM24 e exibiu os menores valores FICI. A associação do ácido úsnico com a gentamicina foi sinérgica sobre as cepas AM18, AM21 e AM24. A associação do ácido úsnico com a penicilina apresentou-se indiferente para todas as cepas exceto para S. aureus AM13. Este estudo demonstrou que o ácido úsnico, quando associado à antimicrobianos fluoroquinolônicos, betalactâmicos e aminoglicosídeos pode agir sinergicamente, inibindo cepas de S. aureus MRSA.

Antimicrobial engineered nanomaterials (ENM) are increasingly incorporated into products despite limited understanding of the interactions between ENMs and bacteria that lead to toxic impacts. The hazard posed by increasing environmental release of antimicrobial ENMs is also poorly characterized. The overall objective of this thesis is to inform questions about the types of interactions that lead to an ENM inducing bacterial toxicity. Many antimicrobial ENMs are soluble, and the ion plays an important role in their toxicity. Some believe that, beyond release of ions, ENM toxicity is expected to derive from a nanoparticle (NP)-specific effect. This research compares bacterial responses to ENMs, their metal salts, and/or their transformed species within different experimental settings to improve our understanding of the interactions that enable ENM bacterial toxicity. The first objective is to characterize the potential hazard posed by pristine and transformed antimicrobial ENMs on microbial communities within a complex environmental system. One pair of ENMs (Ag0 and Ag2S) led to differential short-term impacts on surficial sediment microbial communities, while the other did not (CuO and CuS), showing that ENM transformation does not universally lead to distinct impacts. The metal ion (Cu2+) had a more profound microbial community impact than did any of the four ENMs. By 300 days the microbial community structure and composition re-converged, suggesting minimal long-term impacts of high pulse inputs of antimicrobial ENMs on microbial communities within complex environments. The second objective is to identify NP-specific effects of a common antimicrobial ENM on a model bacterium. Analysis of transcriptional responses identified NP-specific induction of a membrane stress responsive gene, providing evidence of a NP-specific effect. Otherwise, our results suggest that CuO NP toxicity triggers the same stress responses as does Cu2+, but at more moderate levels. Two ion treatments with the same total Cu input – one with pulse addition and one with gradual addition that was meant to better represent the slow dissolution of the CuO NP – led to temporally distinct responses. This calls for the use of more representative ion controls for comparison against soluble NP impacts in future nanotoxicity studies. The third objective is to investigate the potential use of CuO ENMs to reduce virulence and growth of an emerging bacterial pathogen. CuO NP exposure led to reduction in relative expression of three Staphylococcus aureus virulence factor genes, especially in methicillinresistant S. aureus (MRSA) clinical isolates. Growth was inhibited at high CuO NP concentrations for all four isolates, too. Comparison across all genes assayed showed isolatespecific transcriptional responses, but with NP- and ion-induced responses showing clear differences for each isolate, too. Altogether, this research contributes novel knowledge that will guide efforts to characterize potential hazard from release of ENMs into the environment and to apply ENMs for effective antibacterial treatment.

No description available.

Methicillin-resistant Staphylococcus aureus (MRSA) is a growing concern in Canada especially in Aboriginal communities in remote regions. The northern and remote communities possess some or many of the risk factors that are identified in previous research to be associated with Community-Associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) infections such as overcrowding, challenges in maintaining personal hygiene and limited access to healthcare. CA-MRSA spreads rapidly in the communities. It is known to not only affect young and healthy individuals, but it is also associated with high morbidity and mortality rates. Furthermore, antibiotic resistance in CA-MRSA is increasing in Canada. It is known that inappropriate and greater use of antibiotics is associated with increased antibiotic resistance. Resistant CA-MRSA infections are more difficult to treat. To reduce and to control the antibiotic resistance, monitoring the prevalence of CA-MRSA and the changing antibiotic susceptibility profiles at the population level, especially in highly affected communities, is crucial. By monitoring this trend, it will enable healthcare practitioners to provide more adequate and appropriate treatment. To our knowledge, there was no community-based study that examined the epidemiology of CA-MRSA skin and soft-tissue infections (SSTIs) in First Nations communities in Canada at large scale, and the knowledge on the risk factors, outcomes and antibiotic susceptibility profiles is still very limited. This study aimed to describe the local epidemiology of SSTIs at the community level in selected First Nations communities as well as to describe the antibiotic use to treat SSTIs and the antibiotic susceptibility patterns of CA-MRSA. A retrospective chart review was conducted in 12 nursing stations in the First Nations communities across 5 provinces in Canada. The charts of individuals over 18 years of age who had received service at the nursing station in the previous 12 months, starting retrospectively from the date of collection, were reviewed in this study. Each antibiotic prescription that was noted in the chart in this period prior to chart review was recorded in the antibiotic tracking case report form. Data collected included demographics, indication for antibiotic use, antibiotic prescription parameters and patient outcomes. In total, of 372 patient charts reviewed, 224 patient charts contained at least one case (an encounter that resulted in an antibiotic prescription during the study period). Of those 224 charts, 459 cases were recorded and, of those, 137 cases had a diagnosis of an SSTI. In the 65 patients accounting for all cases of SSTI patients, more than 80% of the study population were under the age of 50. The prevalence of impaired renal function was low, diabetes was present in 20% of cases, cardiac disease was present in 15% of cases, and reported alcohol misuse was present in 30% of cases. The presence of indwelling devices was very rare. There were 137 cases of SSTIs over 372 charts reviewed in total. The prevalence of SSTI among the selected First Nations communities in 2012-2013 was estimated at almost 37% (137 cases of SSTIs / 372 charts reviewed). In the 137 SSTI cases, 55 cases were identified as MRSA infections either by laboratory test such as wound culture or by history of colonization documented in the chart. The overall prevalence of MRSA in all SSTI cases was estimated at 40.1% (55 confirmed MRSA positive cases / 137 cases of SSTIs). The majority of SSTIs were purulent infections and wounds. We also found that a wound culture and susceptibility test were performed only in 29% of all SSTI cases. An orally administered antibiotic was most frequently used (in 71.5% of treatments). Topical antibiotics were used in 18.3% and IV antibiotics were used in 8.8%. Other than the antibiotic treatment, wound care was performed in 49% of the SSTI cases and incision and drainage (I&D) procedure in 9%. The majority of MRSA isolates in this study were susceptible to clindamycin and co-trimoxazole (90.5% and 95.2%), but only 29% were susceptible to erythromycin. In general, higher rates of SSTIs were seen in communities where overcrowding and poor access to running water are more prevalent. In this study, we found that the diagnostic tests such as wound culture and sensitivity test was not ordered very often and there was also lack of follow-up or lack of documentation of the follow-up. More research is needed to better understand some of the challenges and risk factors associated with CA-MRSA infections in remote communities. Developing a national-level surveillance system that can help with monitoring the epidemiology of SSTIs and the antibiotic susceptibility test results of CA-MRSA at community level would be essential for better prevention, control, and management. Furthermore, adopting other initiatives such as antibiotic stewardship programs at community and healthcare settings as well as addressing the socio-environmental factors such as housing and access to water would be all very important in the steps to curb antibiotic resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant bacterium of epidemiologic importance in Canadian healthcare facilities. The contact between MRSA colonized or infected patients with other patients, healthcare workers (HCWs) and/or the healthcare environment can result in MRSA transmission and healthcare-associated MRSA (HA-MRSA) infections in hospitals. These HA-MRSA infections are linked with increased length of hospital stay, economic burden, morbidity and mortality. Although infection prevention and control programs initiated in 2009 in Canada and other developed countries (e.g., UK, France, Belgium, Denmark, etc.) have been relatively successful in reducing the rate of HA-MRSA infections, they continue to pose a threat to patients, especially to the more vulnerable in long term care and geriatric institutions. Historically, MRSA was a problem mainly in hospital settings but after mid-1990s new strains of MRSA have been identified among people without healthcare-related risks and have been classified as community-associated MRSA (CA-MRSA). Furthermore, the distinction between HA-MRSA and CA-MRSA strains is gradually waning due to both the introduction of HA-MRSA in communities, and the emergence of CA-MRSA strains in hospitals. The purpose of this thesis was to explore the feasibility of constructing healthcare networks to evaluate the role of healthcare providers (e.g., physicians) and places (e.g., patient rooms) in the transmission of MRSA in a large tertiary care facility. Method of investigation: a secondary data case-control study, using individual characteristics and network structure measures, conducted at The Ottawa Hospital (TOH) between April 1st, 2013 and March 31th, 2014. Results: It was feasible to build social networks in a large tertiary care facility based on electronic medical records data. The networks' size (represented by the number of vertices and lines) increased during the outbreak period (period 1) compared to the pre-outbreak period (period 0) for both groups and at all three TOH campuses. The calculated median degree centrality showed significant increase in value for both study groups during period 1 compared to period 0 for two of the TOH campuses (Civic and General). There was no significant difference between the median degree centrality calculated for each study group at the Heart Institute when compared for the two reference periods. The median degree centrality of the MRSA case group for period 0 showed no significant difference when compared to the same measure determined for the control group for all three TOH campuses. However, the median degree centrality calculated for period 1 was significantly increased for the control group compared to the MRSA case group for two TOH campuses (Civic and General) but showed no significant difference between the two groups from the Heart Institute. In addition, there was a correlation between the two network measures (degree centrality and eigenvector centrality) calculated to determine the most influential person or place in the MRSA case group networks. However, there was no correlation between the two network’s measures calculated for physicians included in MRSA case group networks. Conclusions: It is feasible to use social network analysis as an epidemiologic analysis tool to characterize the MRSA transmission in a hospital setting. The network's visible changes between the groups and reference periods were reflected by the network measures and supported also by known hospital patient movements after the outbreak onset. Furthermore, we were able to identify potential source cases and places just prior of the outbreak start. Unfortunately, we were not able to show the role of healthcare workers in MRSA transmission in a hospital setting due to limitations in data collection and network measure chosen (eigenvector centrality). Further research is required to confirm these study findings.

Bacterial infections remain a significant threat to human health. Due to the emergence of widespread antibiotic resistance, development of novel antibiotics is required in order to ensure that effective treatment remains available. The aim of this study was to isolate and identify the fraction responsible for the antimicrobial activity in Tabernaemontana elegans (Stapf.) root extracts. The active fraction was characterised by thin layer chromatography (TLC) and gas chromatography – mass spectrometry (GC-MS). Antibacterial activity was determined using the broth micro-dilution assay and antimycobacterial activity using the BACTEC radiometric assay. Cytotoxicity of the crude extract and fractions was assessed against primary cell cultures; lymphocytes and fibroblasts; as well as a hepatocarcinoma (HepG2) and macrophage (THP-1) cell line using the Neutral Red uptake and MTT assays. The crude root extracts were found to contain a high concentration of alkaloids (1.2% w/w). GC-MS analysis identified the indole alkaloids, voacangine and dregamine, as major components. Antibacterial activity was limited to the Gram-positive bacteria and Mycobacterium species, with MIC values in the range of 64 – 256 ìg/ml. When combined with antibiotics, additive antibacterial effects were observed. Marked cytotoxicity to all cell lines tested was evident in the MTT and Neutral Red uptake assays, with IC50 values ranging between 1.11 – 9.81 ìg/ml. This study confirms the antibacterial activity of T. elegans and supports its potential for being investigated further for the development of a novel antibacterial compound. / Dissertation (MSc)--University of Pretoria, 2011. / Pharmacology / unrestricted

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-21T17:43:23Z No. of bitstreams: 1 thiagocesarnascimento.pdf: 3494952 bytes, checksum: 3356415ad599be16280e8e70cee1950d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T18:47:50Z (GMT) No. of bitstreams: 1 thiagocesarnascimento.pdf: 3494952 bytes, checksum: 3356415ad599be16280e8e70cee1950d (MD5) / Made available in DSpace on 2016-01-25T18:47:50Z (GMT). No. of bitstreams: 1 thiagocesarnascimento.pdf: 3494952 bytes, checksum: 3356415ad599be16280e8e70cee1950d (MD5) Previous issue date: 2014-04-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Staphylococcus aureus é uma das principais causas de infecções associadas à saúde em todo o mundo. O objetivo deste trabalho foi avaliar as características epidemiológicas, fisiológicas e moleculares de S. aureus resistente à oxacilina (ORSA), isolados de infecções em um hospital terciário universitário e avaliar sua susceptibilidade a novas moléculas síntéticas. Foram avaliadas um total de 103 amostras de ORSA quanto a dados clínicos e epidemiológicos relacionados aos pacientes, perfil de susceptibilidade a drogas antimicrobianas, avaliação da produção de biofilme e da capacidade hemolítica e confirmação da identidade genética, detecção do gene mecA e caracterização do SCCmec, por PCR. Para 45 amostras oriundas do CTI, também foram realizadas a análise do perfil de fragmentação do DNA cromossômico por PFGE e caracterização do CC, por PCR. Para 21 amostras foi avaliada a susceptibilidade a aminas aromáticas alquiladas (aminoálcoois). Considerando-se as amostras clínicas, a maioria das amostras foi isolada no sexo masculino (71%) a partir de secreção traqueal (26,2%) e sangue (23,3%) seguido de swab de sítio cirúrgico e ponta do cateter (15,5%), exsudados (14,6%) e urina (4,9%), associados à infecção do sistema respiratório (34%) e bacteremia (20,4%), em unidade de terapia intensiva (43,7%). No geral, uma alta frequência de resistência foi observada contra clindamicina (100%), eritromicina (100%), azitromicina (99%), levofloxacina (93,2%), gentamicina (84,5%), sulfametoxazol-trimetoprim (75,7%), tetraciclina (77,6%), cloranfenicol (59,3%) e rifampicina (50,5%). Os aminoálcoois também apresentaram atividade antibacteriana contra a maioria dos isolados de ORSA. Tipos de SCCmec III (66,7%) , II (17,8%) , IV (4,4% ), I (2,2%) foram encontrados. A maioria (66,7%) dos isolados foram relacionados ao clone epidemico brasileiro (CEB)/CC8/SCCmec III , que prevaleceu entre 2005 e 2008 , enquanto que a linhagem USA100/CC5/SCCmec II surgiu em 2007 e foi mais frequente em 2009 e 2010, na UTI. Os isolados que transportam o tipo de SCCmec IV (USA400/CC1 e USA800/CC5 linhagens) e I (USA500/CC5) também foram detectadas. Nossos dados são altamente relevantes para os sistemas de vigilância permitiu mapear em maior escala a circulação dinâmica de ORSA e levantar discussões sobre estratégias de contenção e uso racional da quimioterapia empírica. / Staphylococcus aureus is a major cause of health care associated infections worldwide. The aim of this work was to evaluate epidemiological, physiological and molecular characteristics of aureus oxacillin resistant S. aureus (ORSA) isolated from infections in a tertiary university hospital and evaluated their susceptibility to new synthetic molecules. A total of 103 samples of ORSA for clinical and epidemiological data related to patients susceptibility profile to antimicrobial drugs, assessment of biofilm production and hemolytic capacity and confirmation of genetic identity, detection of the mecA gene and characterization of SCCmec were evaluated, PCR. For 45 samples from CTI, also the profile of DNA analysis by PFGE and characterization of the CC, PCR were performed. For 21 samples susceptibility to alkylated aromatic amines was evaluated. Considering the clinical samples, most samples contained in males (71%) from tracheal secretion (26.2%) and blood (23.3%) followed by surgical site and swab tip of the catheter (15.5%), exudates (14.6 %) and urine (4.9%), associated with infection of the respiratory system (34%) and bacteremia (20.4%) in the intensive care unit (43.7%). Overall, a high frequency of resistance was observed against clindamycin and erythromycin (100%), azithromycin (99%), levofloxacin (93.2%), gentamicin (84.5%), trimethoprim-sulfamethoxazole (75.7%), tetracycline (77.6%), chloramphenicol (59.3%) and rifampicin (50.5%). The amino alcohols also showed antibacterial activity against most isolates of ORSA. SCCmec type III (66.7%), II (17.8%), IV (4.4%) and I (2.2%) were found. The majority (66.7%) isolates were related to the brazilian epidemic clone (CEB)/CC8/SCCmec III, which prevailed between 2005 and 2008, while the USA100/CC5/SCCmec lineage II emerged in 2007 and was more frequent in 2009 and 2010 in the ICU. The strains carrying the SCCmec type IV (USA400/CC1 and USA800/CC5 lineages) and I (USA500/CC5) were also detected. Our data are highly relevant to surveillance systems enabled map on a larger scale the dynamic movement of ORSA and raise discussions on containment strategies and rational use of empirical chemotherapy.

L'objectif était d'étudier l'histoire naturelle de la colonisation nasale par S. aureus, en particulier l'impact des antibiotiques sur l'acquisition et la persistance de S. aureus résistant (SARM) ou sensible à la méticilline (SASM). Ce travail s'est appuyé sur les données issues d'une cohorte prospective multicentrique incluant des patients hospitalisés dans des centres de médecine physique et réadaptation et non colonisés par S. aureus à l'admission. 1) Les facteurs de risque d'acquisition de SARM et de SASM ont été examinés à l'aide d'une analyse cas-cas-témoins nichée. L'utilisation de fluoroquinolones, le sexe masculin et une plus grande intensité des soins à l'admission étaient significativement associés à l'acquisition de SARM. L'aide à la toilette et l'utilisation d'un dispositif urinaire étaient significativement associées à l'acquisition de SASM. 2) Les facteurs influençant la perte de colonisation ont été examinés à l'aide de modèles de Cox à fragilité partagée. L'utilisation de fluoroquinolones et la présence d'une plaie positive pour une souche différente de celle du nez étaient significativement associées à la décolonisation de SASM. Le phénotype de résistance à la méticilline n'était pas associé à la durée de colonisation par S. aureus, les durées médianes estimées de colonisation par SARM et par SASM étant respectivement de 3 et 2 semaines. Ce travail offre un nouvel éclairage sur l'histoire naturelle de la colonisation nasale par S. aureus en discriminant les facteurs relatifs à la forme résistante et à la forme sensible de la bactérie. Ces résultats montrent un impact différentiel des fluoroquinolones sur l'acquisition et la persistance de SARM ou de SASM. / The objective was to study the natural history of nasal S. aureus colonization, particularly the impact of antibiotics on methicillin-resistant (MRSA) or methicillin-sensitive (MSSA) S. aureus acquisition and persistence. This work was based on data provided by a prospective multicenter cohort including patients hospitalized in long-term-care facilities and not colonized with S. aureus at admission. 1) Risk factors for MRSA or MSSA acquisition were investigated using a nested case-case-control analysis. Fluoroquinolone use, male sex and more intensive care at admission were significantly associated with MRSA acquisition. Body-washing assistance and use of a urination device were significantly associated with MSSA acquisition. 2) Factors influencing the time to loss of colonization were investigated using shared-frailty Cox models. Fluoroquinolone use and the presence of a wound positive for a non-nasal strain were significantly associated with MSSA decolonization. The methicillin resistance phenotype was not associated with S. aureus colonization duration, and estimated median time to MRSA or MSSA decolonization was 3 or 2 weeks respectively. This work provides new insights into the natural history of nasal S. aureus colonization discriminating factors for the methicillin-resistant or -sensitive phenotypes of the bacteria. These results strongly suggest a distinct impact of fluoroquinolones on MRSA or MSSA acquisition and persistence.