Mycobacterium tuberculosis (M.tb) l'agent étiologique de la tuberculose infecte un tiers de la population mondiale avec 9 millions de nouveaux cas et 1.5 millions de décès chaque année. La capacité de la bactérie à persister dans son hôte ainsi que l'apparition croissante de souches multi-résistantes voire totalement résistantes expliquent ces statistiques dramatiques. La découverte de nouveaux traitements à travers une meilleure connaissance de la physiologie et des programmes génétiques adaptatifs du pathogène est donc une priorité mondiale. M.tb est un bacille à Gram+ avec une enveloppe particulière caractérisée par une membrane externe (la mycomembrane) essentielle à sa viabilité et sa virulence. Cette membrane est constituée majoritairement d'acides mycoliques (AMs), des acides gras à très longues chaînes modifiés par l'introduction de groupements fonctionnels. Bien qu'à ce jour la biosynthèse des AMs est relativement bien caractérisée d'un point de vue biochimique, certaines données nécessitent d'être confirmées in vivo, de même qu'il existe peu d'information sur la régulation et la contribution des gènes de biosynthèse à la capacité adaptative des mycobactéries. Une trentaine de gènes sont impliqués dans la biosynthèse des AMs dont hadA, hadB et hadC codant pour une réaction de déshydratation essentielle. Il a été démontré biochimiquement que HadB porte l'activité catalytique et que HadA et HadC apportent la spécificité de substrats. Au cours de ma thèse, par une approche génétique, nous avons montré que seule HadB était essentielle à la viabilité mais que HadA et HadC bien que non essentielles jouaient un rôle majeur dans la physiologie, la capacité adaptative et la virulence des mycobactéries, en relation avec leur rôle dans la structure des AMs. Ces résultats avaient non seulement confirmé les données biochimiques quant au rôle de HadC dans la biosynthèse des AMs, mais également souligné l'intérêt d'une stratégie de lutte basée sur l'affaiblissement du fitness de M.tb, rendant ainsi le pathogène plus sensible aux traitements déjà existants ainsi qu'aux défenses naturelles de l'hôte. Une analyse phylogénétique couplée à une analyse expérimentale de l'expression des gènes nous a permis de retracer et de rationaliser le scénario évolutif qui a façonné le locus hadABC. En accord avec l'organisation génétique, j'ai ainsi montré que la carence en nutriments, un stress rencontré par la bactérie lors de l'infection, conduisait à la co-répression des gènes hadABC ainsi que de la plupart des gènes de biosynthèse des AMs avec des gènes impliqués dans le processus de traduction. Le potentiel de traduction est connu pour être contrôlé par la disponibilité en nutriments, à travers notamment la réponse stringente, une réponse adaptative universellement conservée chez les bactéries. Suite à ces résultats, un modèle a été proposé selon lequel au cours de la réponse stringente, les intermédiaires de synthèse des AMs, seraient détournés au profit de la synthèse de lipides alternatifs dont des lipides de stockage. L'analyse phylogénétique a également suggéré une relation fonctionnelle étroite entre l'activité des enzymes HadABC et des enzymes responsables de la modification des AMs. Afin d'avoir une vision intégrée de la régulation de la synthèse de la mycomembrane, nous avons analysé le rôle biologique du gène rv0081 codant pour un facteur de transcription global. Différentes approches systémiques suggéraient que Rv0081 jouerait un rôle central dans la capacité adaptative de M.tb en régulant de nombreux gènes impliqués dans différentes fonctions cellulaires dont les gènes hadABC. J'ai pu montrer qu'un mutant rv0081 était hypervirulent et que l'absence d'une régulation naturelle du gène affectait la capacité de survie de la bactérie à l'intérieur des macrophages. / Mycobacterium tuberculosis (M.tb), the causative agent of tuberculosis infects one third of the world population with 9 million new cases and 1.5 million deaths each year. The capability of the bacteria to persist in its host and the emergence of multi- and totally-drug resistant strains explain these dramatic statistics. Therefore, the discovery of new drugs through a better understanding of the physiology and of the adaptive genetic programs of the pathogen is a priority. Mtb is a Gram + bacilli with an unusual cell envelope characterized by an outer membrane (the mycomembrane) essential to its viability and virulence. This membrane is mainly composed of mycolic acids (MAs), a class of very long chain fatty acids which are modified by the introduction of functional groups. To date the biosynthesis of MAs is biochemically well characterized, but some data need to be confirmed in vivo, likewise there is little information about the regulation and the contribution of biosynthesis genes in the adaptive capacity of mycobacteria. Around thirty genes are involved in the biosynthesis of MAs including hadA, hadB and hadC which are required for an essential dehydration reaction. It has been shown biochemically that HadB bears the catalytic activity and that HadA and HadC bring about the substrate specificity. In this study, using a genetic approach, we have shown that only HadB was essential to the viability but that the non-essential HadA and HadC proteins played a major role in the physiology, the adaptive capacity and the virulence of mycobacteria. These results have not only confirmed the biochemical data on the role of HadC in the biosynthesis of MAs, but have also underlined the relevance of a strategy based on weakening the fitness of Mtb, making the pathogen more susceptible to existing therapy as well as to the natural host defenses. Phylogenetic and experimental analyses of gene expression allowed us to rationalize the evolutionary scenario that has shaped the hadABC locus. In agreement with the genetic organization, I have shown that starvation, a stress experienced by the bacterium upon infection, resulted into the co-repression of the genes hadABC as well as most of the MAs biosynthetic genes with genes involved in the translation process. The translation potential is known to be controlled by nutrient avaibility, especially through the stringent response, an adaptive response widely conserved in bacteria. Following these results a model was proposed stating that during the stringent response, the MAs intermediate products would be redirected toward the synthesis of alternate lipids including storage lipids. Phylogenetic analysis also suggested a close functional relationship between the activity of HadABC proteins and the enzymes involved in the modification of MAs. In order to get an integrated picture of the regulation of the biosynthesis of the mycomembrane, we analyzed the biological role of rv0081, a gene encoding a transcription factor. Various comprehensive approaches suggested that Rv0081 plays a key role in M.tb adaptive capacity through the regulation of many genes involved in various cellular functions including the hadABC genes. In my PhD work I have shown that an rv0081 deleted strain was hypervirulent and that the inability of the bacteria to properly regulate the gene had prevented the bacteria to survive within macrophages.

<p>IIn the first study, we investigated the functional implications of prolonged TLR signalling on IFN-γ mediated killing of mycobacteria by murine macrophages <i>in vitro</i>. TLR2, but not TLR4 ligation interfered with IFN-γ mediated killing of mycobacteria in macrophages. In terms of mechanisms, neither TNF nor nitric oxide (NO) production was significantly affected, and the refractoriness induced could be reversed with increasing amounts of IFN-γ In the second study, we aimed to identify immunological markers of diagnostic importance in both the respiratory tract and serum during pulmonary mycobacterial infection in mice. We found that increased levels of immunological markers in the respiratory tract, but not serum, correlated better with active mycobacterial infection in the lungs, suggesting that the immune response in the respiratory tract is more reflective of the infection status and pathology than the systemic response. Finally, we investigated the level and nature of immune responses to pulmonary mycobacterial infection in BALB/c and C57BL/6 mice, two mouse strains known to exhibit different susceptibilities to infection with several intracellular pathogens, including mycobacteria. We showed that increased susceptibility of BALB/c mice to early mycobacterial infection was associated with reduced Th1 immune responses, and increased sTNFR secretion in the lung. Moreover, BALB/c mice recruited fewer monocytes/macrophages to the lung, and although IFN-γ stimulation of infected bone marrow derived macrophages in both mouse strains resulted in induction of antimycobacterial activity, BALB/c mice had a reduced capacity to kill ingested bacteria. The work presented in this thesis provide further insight into the mechanisms involved in the host-pathogen interaction; from persistence, to the immunological processes induced by the pathogen, to susceptibility of the host to infection.</p>

IIn the first study, we investigated the functional implications of prolonged TLR signalling on IFN-γ mediated killing of mycobacteria by murine macrophages in vitro. TLR2, but not TLR4 ligation interfered with IFN-γ mediated killing of mycobacteria in macrophages. In terms of mechanisms, neither TNF nor nitric oxide (NO) production was significantly affected, and the refractoriness induced could be reversed with increasing amounts of IFN-γ In the second study, we aimed to identify immunological markers of diagnostic importance in both the respiratory tract and serum during pulmonary mycobacterial infection in mice. We found that increased levels of immunological markers in the respiratory tract, but not serum, correlated better with active mycobacterial infection in the lungs, suggesting that the immune response in the respiratory tract is more reflective of the infection status and pathology than the systemic response. Finally, we investigated the level and nature of immune responses to pulmonary mycobacterial infection in BALB/c and C57BL/6 mice, two mouse strains known to exhibit different susceptibilities to infection with several intracellular pathogens, including mycobacteria. We showed that increased susceptibility of BALB/c mice to early mycobacterial infection was associated with reduced Th1 immune responses, and increased sTNFR secretion in the lung. Moreover, BALB/c mice recruited fewer monocytes/macrophages to the lung, and although IFN-γ stimulation of infected bone marrow derived macrophages in both mouse strains resulted in induction of antimycobacterial activity, BALB/c mice had a reduced capacity to kill ingested bacteria. The work presented in this thesis provide further insight into the mechanisms involved in the host-pathogen interaction; from persistence, to the immunological processes induced by the pathogen, to susceptibility of the host to infection.

Bacterial cells were once treated as membrane-enclosed bags of cytoplasm: a homogeneous, undifferentiated suspension in which polymers (proteins, nucleic acids, etc.) and small molecules diffused freely to interact with each other. Biochemical studies have determined the molecular mechanisms underlying the biological processes of metabolism, replication and transcription-translation, etc. However, recent advancements in optical techniques armed with fluorescent tags for proteins and nucleic acids have increased our ability to peer into the interior of live bacterial cells. This has revealed an organized layout of multi-protein complexes, or molecular machines, dedicated to specific functions at defined sub-cellular locations; the timing of their assembly and/or rates of their activity being determined by available nutrition and environmental signals from the niche occupied by the organism. In the present study, we have attempted to identify the intracellular location and organization of the molecular machines assembled for protein synthesis (ribosomes), DNA replication (replisomes) and cell division (divisome) in different bacteria. We have used the model system Escherichia coli as well as Helicobacter pylori and mycobacterial strains (Mycobacterium marinum and Mycobacterium smegmatis), which grow at different rates and move to dormancy late into stationary phase Bacterial nucleoid plays a major role in organizing the location and movement of active ribosomes, replisomes and placement of divisome. While the active ribosomes appear to follow the dynamic folds of the bacterial nucleoid during cell growth in E. coli, inactive ribosomes appear to accumulate near the periphery. The replisome in H. pylori was visualized as a sharp, single focus upon SSB and DnaB co-localization in growing helical rods but disassembled into diffused fluorescence when the cells attained non-replicative coccoid stage. Our investigation into mycobacterial life-cycle revealed unique features such as an absence of a dedicated mid-cell site for divisome assembly and endosporulation upon entry into stationary phase. In brief, we present the cell cycle-dependent subcellular organization of molecular machines in bacteria.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2009. / Härtill 5 uppsatser.

Made available in DSpace on 2014-06-11T19:32:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-18Bitstream added on 2014-06-13T19:43:46Z : No. of bitstreams: 1 jordaojunior_cm_dr_arafcf.pdf: 786872 bytes, checksum: 274f8014be73a7e236d6f75ebb8adc01 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Micobacterias ambientais (MA) ou micobactérias não-tuberculosas (MNT) estão relacionadas a uma grande variedade de doenças em seres humanos. As micobactérias ambientais são saprófitas comumente encontradas em todos os ecossistemas, incluindo água, solo, alimento, poeira e aerósóis. Particularmente, essas micobactérias podem se multiplicar em diferentes fontes de águas, como por exemplo águas de superfície, recreação, residuais, subterrâneas e de torneiras. Sistemas de encanamentos fornecedores de águas são rapidamente colonizados por micobactérias e assim os biofilmes formados nos canos d´água servem como fontes desses microrganismos. Micobactérias são resistentes contra a maioria dos desinfetantes usuais e podem tolerar grandes variações de pH e temperatura, o que lhes permite a permanência nos sistemas de distribuição de água por longos períodos de tempo. O objetivo desse estudo foi isolar e identificar MNT de amostras de água e biofilmes na canalização de água de uma fazenda produtora de leite de búfalas na região de São Carlos-SP e também avaliar a qualidade da água da propriedade por meio da contagem de microrganismos heterotróficos, coliformes totais e termotolerantes e Staphylococcus aureus.Das amostras analisadas, 90,5% das amostras foram classificadas como fora dos padrões em relação a coliformes totais e 69% foram classificadas como fora dos padrões em relação a coliformes termotolerantes. Trinta e duas amostras (76,3%) de um total de 42(100%) apresentaram populações acima de 500 UFC/mL para bactérias heterotróficas. S.aureus foram isolados em 9 amostras (32,14%) de um total de 28(100%). De um total de 33 (100%)MNT isoladas nesse trabalho, 12 (36,36%) foram isoladas de biofilmes presentes nos encanamentos de água da propriedade. Esses isolados foram posteriormente identificados usando a técnica do PRA (PCR- restriction enzyme... / Environmental mycobacteria (EM) or nontuberculosis mycobacteria (NTMs) are implicated in a variety of human diseases. They are common saprophytes in all ecosystems, including water, soil, food, dust, and aerosols. In particular, EM species can multiply in numerous water sources, including wastewater, surface water, recreational water, ground water, and tap water. Piped water supplies are readily colonized by mycobacteria, and thus the biofilm in the water pipes may serve as a reservoir for these organisms. Mycobacteria are resistant against common disinfectants and can tolerate wide ranges of pH and temperature, which allows them to persist in drinking water systems for long periods of time.The aim of this study was to isolate and identify NTMs from water samples and biofilms from a dairy buffalo farm in São Carlos city, State of Sao Paulo and to evaluate the water quality of the farm using heterotrophic, faecal and total coliforms count plates. Results showed that 90.5% of the samples were considered as being out of the standards related to total coliforms and 69% of the samples were classified as being out of the standards related to faecal coliforms. From a total of 42 (100%) samples, 32 (76,3%) presented populations above of 500 CFU/mL for heterotrophic bacteria. S.aureus were isolated in 9 samples (32,14%) from a total of 28(100%).Out of 33(100%) NTMs isolated in this work, 12 (36,36) were isolated from biofilms in water pipes. These isolates were further identified using PRA (PCR- restriction enzyme analysis), as well as 16S rDNA and hsp65 DNA sequencing, and mycolic acids by thin layer chromatography (TLC). Twenty-eighty species (84,84%) were identified as M. gordonae (18 isolates from water samples and 10 from biofilms), 2 (2,06%) M. lentiflavum (biofilms), 2 (2,06%)... (Complete abstract click electronic access below)

Orientador: Márcio Garcia Ribeiro / Resumo: Foram investigadas, neste estudo, proteínas associadas à virulência (genes vapA, vapB e vapN) das espécies de Rhodococcus equi e Micobactérias isoladas de 330 linfonodos de catetos (Tayassu tajacu) e queixadas (Tayassu pecari) destinados ao consumo humano. Trinta e seis (10,9%) linhagens de R. equi foram isoladas, 3,3% (11/330) dos linfonodos de queixadas e 7,6% (25/330) dos catetos. Entre os 11 isolados de R. equi das queixadas, 90,9% (n=10/11) foram obtidos de linfonodos mesentéricos e apenas 9,1% (n=1/10) de linfonodo mediastínico. Nos 25 isolados de R. equi dos catetos, 40,0% (10/25) foram obtidos de linfonodos mesentéricos, 36,0% (9/25) de submandibulares e 24,0% (6/25) de mediastínicos. Não foram identificados genes vapA, vapB e vapN entre os isolados de R. equi. Foi isolado Mycobacterium sp. de 3,03% (10/330) do total de linfonodos. Entre os 10 isolados de micobactérias, 60% (n=6/10) dos linfonodos eram de queixadas e 40% (4/10) de catetos. Dez espécies de Mycobacterium foram detectadas por PCR-PRA, com predominância de M. avium tipo 1. O sequenciamento dos genes hsp65 e rpob revelaram micobactérias saprófitas (M. sinense, M. kumamotonense) e potencialmente patogênicas (M. colombiense, M. intracellulare) para humanos e animais. Esta é a primeira descrição de R. equi e / ou espécies de micobactérias identificadas nos linfonodos de espécimes de Tayassuideos. Apesar da ausência de genes Vap, a identificação de R. equi, bem como de micobactérias não tuberculosas e saprófit... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Virulence-associated proteins (vapA, vapB and vapN genes) of Rhodococcus equi and Mycobacterium species isolated from 330 lymph nodes of collared peccaries (Tayassu tajacu) and white-lipped peccaries (Tayassu pecari) intended for human consumption were investigated. Thirty-six (10.9%) R. equi strains were isolated, 3.3% (11/330) from white-lipped peccary and 7.6% (25/330) of collared peccary lymph nodes. Among the 11 isolates of R. equi of the white-lipped peccaries, 90.9% (n = 10/11) were obtained from mesenteric lymph nodes and only 9.1% (n = 1/10) of the mediastinal lymph node. In the 25 isolates of R. equi obtained from collared peccaries, 40.0% (10/25) were recovered from mesenteric lymph nodes, 36% (9/25) from submandibular, and 24.0% (6/25) from mediastinal ones. No vapA, vapB, and vapN genes (plasmidless type) were identified among R. equi isolates. Mycobacterium sp. was isolated in 3.03% (10/330) of all lymph nodes analyzed. Among the 10 mycobacterial isolates, 60% (n = 6/10) were from white-lipped peccary, and 40% (4/10) from collared peccary lymph nodes. Ten Mycobacterium species were detected by PCR-PRA, with predominance of M. avium type 1. Sequencing of hsp65 and rpob genes revealed mycobacteria that were saprophytic (M. sinense, M. kumamotonense) and potentially pathogenic (M. colombiense, M. intracellulare) to humans and animals. To our knowledge, this is the first description of R. equi and/or mycobacteria species identified in the lymph nodes of Tayassuid sp... (Complete abstract click electronic access below) / Doutor

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2012-11-30T21:17:29Z No. of bitstreams: 1 Juliana Perrone Bezerra De Menezes Avaliacao do papel... - 2005.pdf: 32348298 bytes, checksum: 109d71b2fb835421caaa135becd309de (MD5) / Made available in DSpace on 2012-11-30T21:17:29Z (GMT). No. of bitstreams: 1 Juliana Perrone Bezerra De Menezes Avaliacao do papel... - 2005.pdf: 32348298 bytes, checksum: 109d71b2fb835421caaa135becd309de (MD5) Previous issue date: 2005 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil / Micobactérias ambientais podem ser encontradas em água, solo, poeira, alimentos e animais. A importância do estudo dessas micobactérias tem aumentado nos últimos anos, principalmente, devido a predisposição de pacientes com imunodeficiência à infecção por essas espécies de micobactéria. Além disso, a exposição a micobactérias ambientais pode constituir um dos fatores associados à baixa eficácia da imunização com a vacina BCG. As manifestações da doença, assim como a manutenção da infecção micobateriana, dependem da interação entre a micobactéria e o sistema imune do hospedeiro. O presente trabalho teve como objetivo avaliar a resposta de macrófagos peritoneais de camundongos susceptíveis BALB/c infectados com M intracellulare ou M fortuitum. Macrófagos peritoneais de camundongos BALB/c foram infectados por M intracellulare ou M fortuitum e as diferenças entre essas duas espécies quanto à capacidade de infectar e sobreviver no interior de macrófagos primários, tratados ou não com IFN-y, e produzir óxido nítrico foram avaliadas. Foi observado que os macrófagos infectados com M fortuitum apresentam um maior percentual de células infectadas que aqueles infectados com M. intracellulare, após 4, 24 e 48 horas de infecção. Entretanto, tanto M. fortuitum quanto M intracellulare são capazes de sobreviver no interior de macrófagos peritoneais, pois não há alteração da carga bacilar dessa duas espécies de micobactéria ao longo da infecção. Observamos ainda que M. intracellulare induziu uma maior produção de óxido nítrico por macrófagos primários infectados e tratados por IFN-y que M fortuitum. No entanto, o pré-tratamento com IFN-y não alterou o percentual de células infectadas nem a viabilidade de M intracellulare ou M. fortuitum. Os dados obtidos neste trabalho mostram que, in vitro, M. fortuitum e M. intracellulare interagem de formas distintas, levando á diferentes respostas do macrófago e a destinos intracelulares distintos. Além disso, mostramos que M intracellulare e M. fortuitum são resistentes ao óxido nítrico produzido por macrófagos após ativação por IFN-y. / Environmental mycobacteria are found in water, soil, dust, food and animals. Environmental Mycobacterium importance has increased in the last few years, mostly because of immunodeficient patient predisposition to infection. Moreover, exposure to environmental mycobacteria could be associated to low levels of protection induced by immunization with BCG. Disease manifestations as well as infection outcome depend on interaction between mycobacteria and host immune system. The goal of this work was to evaluate peritoneal macrophage response, from the susceptible BALB/c mice, to M. intracellulare or M. fortuitum infection. Peritoneal inflammatory macrophages, pre-activated or not with IFN-y, were infected by M. intracellulare or M fortuitum and diferences between these two species related to the capacity to infect macrophages, to survive intracellularly and to induce NO production were evaluated. It was observed that the percentage of M. fortuitum-xnÍQoXQá cells was higher related to M. intracellulare-míecieá ones, after 4, 24 and 48 hours of infection. In addition, both M. fortuitum and M. intracellulare presented the ability to survive in peritoneal macrophages. It was also observed that in response to IFN-y activation, M. intracellulare induced higher NO production thanM fortuitum. However, pre-activation with IFN-y did not modify, neither the percentage of M. intracellulare and M. fortuitum infected cells, nor intracellular bacillum survival. These data demonstrate that, in vitro., M. fortuitum and M. intracellulare differently interact with macrophages, inducing diferent macrophage reponses and that both M. intracellulare and M fortuitum are resistant to NO production upon IFN-y activation.

Surtos associados às micobactérias de crescimento rápido (MCR) têm sido cada vez mais relatados em todo o mundo, inclusive no Brasil. Entre as MCR, o complexo M. abscessus é o mais patogênico e relacionado a multirresistência. Considerando a importância de investigar as cepas de MCR presentes em nosso Estado, este estudo teve como objetivos avaliar o perfil molecular e de suscetibilidade caracterizando os isolados de MCR encaminhados para o Centro de Referência em Micobactérias do Estado (Instituto de Pesquisas Biológicas - Laboratório Central de Saúde Pública, IPB-LACEN/RS). Além disso, foram avaliados os mecanismos de resistência à FQ conferido pelos genes gyrA e gyrB. Foram encaminhadas para o IPB-LACEN/RS, entre 2007 a 2012, 74 isolados clínicos. No total, 43 isolados relacionados a surto e 31 isolados de MCR não relacionados a surtos foram analisados. Pela técnica de PRA-hsp65 foi possivel identificar 43 isolados como M. abscessus tipo 2, 21 isolados como M. fortuitum tipo 1 e 10 isolados como M. abscessus tipo 1. Através do sequenciamento parcial do gene rpoB, foi confirmada a identificação de M. abscessus tipo 2 como M. abscessus subsp. bolletii, M. abscessus tipo 1 como M. abscessus subsp. abscessus e M. fortuitum tipo 1 como M. fortuitum subsp. fortuitum. Pela técnica de tipagem PFGE todos os isolados de M. abscessus subsp. bolletii apresentaram o mesmo perfil clonal o qual pertence ao clone BRA100, já descrito mundialmente. Os isolados de M. abscessus subsp. abscessus e M. fortuitum subsp. fortuitum apresentaram perfis distintos de PFGE. O perfil de suscetibilidade aos antibióticos foi avaliado por microdiluição em caldo de acordo com CLSI (2011) e, todos os isolados foram sensíveis a amicacina e todos foram resistentes a doxiciclina e sulfametoxazol-trimetoprima. Para M. abscessus subsp. bolletii todos os isolados foram resistentes à ciprofloxacino, moxifloxacino e tobramicina e um padrão de susceptibilidade variável foi observado para cefoxitina (Sensível - 28%, Intermediário - 72%) e claritromicina (Sensível - 86%, Resistentes - 14%). Cabe mencionar que este é o primeiro relato de resistência a claritromicina para o clone BRA100. Para M. abscessus subsp. abscessus e M. fortuitum subsp. fortuitum todos os isolados foram resistentes a claritromicina; já para a cefoxitina e tobramicina um padrão de susceptibilidade variável foi observado. Todos os isolados de M. fortuitum subsp. fortuitum foram sensíveis à ciprofloxacino, em contraste aos isolados de M. abscessus subsp. abscessus que apresentaram 70% de resistência. Todas MCR, resistentes (ou intermediárias) para ciprofloxacino apresentaram uma Ala-83 em GyrA, em contraste com uma Ser-83 em todos os isolados de M. fortuitum subsp. fortuitum sensíveis a ciprofloxacino, mas com perfil de resistência variável a moxifloxacino. Nenhuma diferença foi encontrada em GyrB independentemente do perfil de sensibilidade de MCR. Em conclusão, nosso estudo relata a persistência de um único clone M. abscessus subsp. bolletii BRA100 relacionado aos surtos, altamente resistente, mesmo após a implementação nacional das medidas de controle de infecção para contenção de surtos por MNTs. Também foi possível correlacionar que mutações no aminoácido Ala-83 de GyrA estão diretamente relacionados com a resistência à ciprofloxacino em M. abscessus subsp. abscessus e M. abscessus subsp. bolletii. / Outbreaks associated with rapidly growing mycobacteria (RGM) have been increasingly reported worldwide, including in Brazil. Among RGM, the M. abscessus complex is consider the most pathogenic, besides being related to multidrug resistance. Considering the importance of investigating the RGM strains present in our state, this study aimed to characterize the molecular and susceptibility profile of RGM isolates referred to the Reference Center for Mycobacteria State (Instituto de Pesquisas Biológicas - Laboratório Central de Saúde Pública, IPB-LACEN/RS). Furthermore, the mechanisms of quinolone resistance conferred by gyrA and gyrB genes were evaluated. A total of 74 isolates was sent to IPB-LACEN/RS between 2007 and 2012. Forty-three of the analyzed isolates were related to outbreak and 31 isolates of RGM were unrelated to outbreaks. The technique of PRA- hsp65 identified 43 isolates as M. abscessus type 2, 21 isolates as M. fortuitum type 1 and 10 isolates as M. abscessus type 1. The partial sequencing of the rpoB gene confirmed the identification of M. abscessus type 2 as M. abscessus subsp. bolletii, M. abscessus type 1 as M. abscessus subsp. abscessus and M. fortuitum type 1 and M. fortuitum subsp. fortuitum. PFGE typing technique showed the same clonal profile for all isolates of M. abscessus subsp. bolletii which belongs to clone BRA100, already described worldwide. Isolates of M. abscessus subsp. abscessus and M. fortuitum subsp. fortuitum showed distinct PFGE profiles. The antibiotic susceptibility profile was evaluated by broth microdilution according to CLSI (2011), and all isolates were susceptible to amikacin and resistant to doxycycline and trimethoprimsulfamethoxazole. All isolates of M. abscessus subsp. bolletii were resistant to ciprofloxacin, moxifloxacin and tobramycin and presented variable susceptibility pattern to cefoxitin (Susceptible - 28%, Intermediate - 72%) and clarithromycin (Susceptible - 86%, Resistant - 14%). It is important to mention that this is the first report of clarithromycin resistance for clone BRA100. Strains of M. abscessus subsp. abscessus and M. fortuitum subsp. fortuitum were all resistant to clarithromycin, and presented a variable susceptibility profile to cefoxitin and tobramycin. All isolates of M. fortuitum subsp. fortuitum were susceptible to ciprofloxacin, in contrast to isolates of M. abscessus subsp. abscessus that showed a resistance rate of 70%. All RGM ciprofloxacin non-susceptible presented an Ala-83 in GyrA, contrasting to a Ser-83 in all isolates of M. fortuitum subsp. fortuitum susceptible to ciprofloxacin, however, with a variable resistance profile to moxifloxacin. No difference was found in GyrB, regardless of the RGM susceptible profile. In conclusion, our study reports the persistence of a single clone of M. abscessus subsp. bolletii BRA100 related to outbreak, highly resistant, even after national implementation of infection control measures to contain outbreaks by NTM. It was also possible to correlate that mutations in the amino acid Ala-83 of GyrA are directly related to ciprofloxacin and moxifloxacin resistance in M. abscessus subsp. abscessus and M. abscessus subsp. bolletii.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Rapidly growing mycobacteria (RGM) are opportunistic human pathogens that are present in our environment. When in biofilms form, mycobacteria are highly resistant to antibacterial treatments. The comprehension of factors that cause mycobacteriosis treatments to fail, e.g., biofilm formation, contributes to the elucidation of the pathogenic potential and the drug resistance shown by these microorganisms. The tested antimicrobials were amikacin, ciprofloxacin, clarithromycin, doxycycline, imipenem and sulfamethoxazole, which are ordinarily employed in the treatment of mycobacteriosis. For each drug, it was evaluated the susceptibility of the pathogen, the ability to inhibit biofilm formation and the resistance of biofilms to antimicrobial activity. Results showed that although the tested antimicrobials are used as an alternative therapy for RGM, Mycobacterium abscessus presented to be resistant to clarithromycin and Mycobacterium massiliense showed a resistant profile to clarithromycin and sulfamethoxazole. Furthermore, the inhibition of biofilm formation and its destruction have not been fully met. The susceptibility profiles found emphasize the need for the determination of drug sensitivity. Considering that the biofilms are a known form of bacterial resistance, the failure of alternatives to inhibit or destroy biofilms can trigger the recurrence of infections. / As micobactérias de crescimento rápido (MCR) são patógenos humanos oportunistas que estão presentes no meio ambiente. Quando em biofilmes, as micobactérias são altamente resistentes aos tratamentos antibacterianos. A compreensão de fatores causadores de falência de tratamentos das micobacterioses, como a formação de biofilmes, contribui para a elucidação do potencial patogênico e da resistência aos fármacos apresentados por esses microrganismos. Foram testados os antimicrobianos amicacina, ciprofloxacino, claritromicina, doxiciclina, imipenem e sulfametoxazol, normalmente empregados no tratamento de micobacterioses. Para cada fármaco, avaliou-se a suscetibilidade do microrganismo, a capacidade de inibição da formação de biofilmes e a resistência dos biofilmes a atuação antimicrobiana. Os resultados demostraram que, embora os antimicrobianos testados sejam empregados como alternativa terapêutica para MCR, Mycobacterium abscessus apresentou-se resistente à claritromicina e Mycobacterium massiliense exibiu perfil resistente à claritromicina e ao sulfametoxazol. Além disso, a inibição da formação de biofilmes e a destruição dos mesmos não foram totalmente alcançadas. Os perfis encontrados reforçam a necessidade da determinação da suscetibilidade aos medicamentos. Tendo-se em vista que os biofilmes constituem uma forma conhecida de resistência bacteriana, o insucesso de alternativas para inibir a formação ou ainda destruir biofilmes pode desencadear a recorrência de infecções.