Este trabalho foi financiado pelo National Institutes of Health (NIH), sob concessão RC3 AI089106. MDR-TB ácidos nucléicos foram fornecidos por / Programa das Nações Unidas Programa Fundo / United Nations Development do Banco Mundial / Organização Mundial da Saúde Especial para Pesquisa e Treinamento em Doenças Tropicais (TDR), Genebra, Suíça. Agradecemos ao Dr. Tom Shinnick dos Centros de Controle e Prevenção de Doenças para orientação sobre os genes e mutações específicas para incluir no ensaio do protótipo.

Para laboratórios que seguem as precauções universais de PCR, é operacionalmente mais eficiente para incluir várias microarrays de amplificação e juntas por substrato e lavar todos os microarrays de amplificação simultaneamente em um recipiente a granel, como descrito aqui. Formatos de consumo estão disponíveis para a realização de pós-amplificação etapas de lavagem microarray em um totalmente selado, teste amplicon fechado, como relatado em outros lugares 30,33. 1. Setup <ol><li> Extrair e purificar ácidos nucléicos a partir da amostra em condições de biossegurança adequadas, com método de escolha. O requisito é que os ácidos nucleicos de ser de pureza suficiente para assimétrica, amplificação por PCR multiplex. </li><li> Prepare espaço de trabalho, limpando superfícies e equipamentos com soluções de descontaminação. </li><li> Coloque reagentes de amplificação no gelo ou bloco frio. </li><li> Rotular um 1,5 ml tubo de microcentrífuga estéril para o master mix de amplificação, e rotular um estéril 0,2 ml de microcentrífuga tuser, para cada amostra. </li><li> Após os reagentes são descongeladas, brevemente vórtex e recolher o conteúdo para o fundo do tubo com um impulso por rotação num mini-centrifugador. Não vortex Taq polimerase. Agite suavemente o tubo para misturar e seguir com um pulso-spin em mini-centrífuga. </li><li> Prepare uma mistura de mestre amplificação usando os volumes de reação por amostra mostrados na Tabela 1. Para dar conta possíveis imprecisões pipetas, prepare-se, pelo menos, mais um volume de reação do que o número total de amostras a ser processados. Note que o master mix contém polimerase Taq adicional, para além daquilo que é fornecido com o tampão de PCR muliplex. Só adicionar o controle de amplificação / inibição à mistura mestre depois de todos os outros reagentes são combinados, e os tubos de reagente estoque voltou ao armazenamento. </li></ol><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> Reagente </td><td> Volume por amostra (mL) </td><td> &lt;strong&gt; final [] </td></tr><tr><td> Mulitplex PCR buffer com HotStar Taq Mais </td><td> 25 </td><td> 1x </td></tr><tr><td> Albumina de soro bovino (BSA) </td><td> 0,55 </td><td> 0,6 mg / mL </td></tr><tr><td> Formamide </td><td> 3.8 </td><td> 7,6% </td></tr><tr><td> Polimerase Taq Adicionais </td><td> 0,8 </td><td> unidades / mL (4 unidades total) </td></tr><tr><td> MDR-TB mistura de iniciadores </td><td> 15.75 </td><td> - </td></tr><tr><td> Livre de RNase H 2 O </td><td> 2.1 </td><td> - </td></tr><tr><td> Amplification / Controle de Inibição </td><td> 1 </td><td> 5,0 fg / ul </td></tr><tr><td> Total </td><td> 49 </td><td></td></tr></tbody></table> MDR-TB amplificação microarray composição master mix Tabela 1.. <ol start="7"><li> Vortex a mistura principal e recolher o conteúdo para o fundo do tubo com um impulso por rotação num mini-centrifugador. </li><li> Combine 49 mL de mistura principal e 1 ml de M. tuberculosis DNA para cada um dos tubos de amostra do passo 1.4, acima. Para uma externa, sem controle modelo (NTC), use 1 ml de água grau biologia molecular no lugar do M. amostra de DNA tuberculose. Vortex e pulso spin-tubo (s) quando terminar. </li></ol> 2. Carregue amplificação Microarrays <ol><li> Adicionar 48 mL de cada mestre mix / amostra para o centro de seus respectivos microarrays, tomando cuidado para não tocar a própria microarray. </li><li> Coloque uma lamela em cima da junta de microarray e selo, tomando cuidado para não prender as bolhas de ar na câmara de microarray. As bolhas de ar podem afetar negativamente a eficiência de amplificaçãoe pode criar artefatos ou ruído na imagem microarray subseqüente. </li></ol> 3. Ciclismo térmica <ol><li> Uma vez que todos os microarrays são carregados com amostra, lugar substratos no termociclador bloco plano. Certifique-se de que a opção tampa aquecida está ligado &quot;Off&quot;. Equipamento obtido a partir Akonni Biosystems já estará pré-qualificados para o uso. Caso contrário, é muito importante verificar se o termociclador bloco plano (s) fornecer (s) uniforme, aquecimento consistente em todos os substratos de microarray. </li><li> Abra o software termociclador, selecione o programa apropriado, digite &quot;50 ul&quot; para o volume de reação, e iniciar a corrida. O protocolo de ciclos térmicos aqui descrito consiste em: <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> Térmicas Ciclismo Passos </td></tr><tr><td> 1 </td><td> 88 ° C </td><td> 5 min </td></tr><tr><td> 2 </td><td> 88 ° C </td><td> 30 seg </td></tr><tr><td> 3 </td><td> 55 ° C </td><td> 1 min </td></tr><tr><td> 4 </td><td> 65 ° C </td><td> 30 seg </td></tr><tr><td> 5 </td><td> Repita os passos (2-4) por 50 ciclos </td></tr><tr><td> 6 </td><td> 65 ° C </td><td> 3 min </td></tr><tr><td> 7 </td><td> 55 ° C </td><td> 3 hr </td></tr></tbody></table></li><li> O número total de ciclos térmicos e 55 ° C pós-amplificação tempo de espera são variáveis ​​independentes que o usuário pode modificar, se necessário ou apropriado para o experimento específico. Porque a mistura de base de MDR-TB cria assimétricos amplicons (predominantemente de cadeia simples), é geralmente útil para incluir ciclos térmicos mais do que de outro modo poderiam ser utilizados para uma amplificação exponencial protocolo convencional de PCR. </li><li> Quando o programa de ciclismo e hibridização térmica é completa, terminar o programa, retire os microarrays de amplificação, feche o software e desligue o termociclador (s).</li></ol> 4. Lavar e secar <ol><li> Para a lavagem até 24 substratos simultaneamente, preparar, pelo menos, 250 ml de 1x SSPE - 0,1% de Triton X-tampão de lavagem 100, e dois recipientes com, pelo menos, 250 ml de água desionizada ou água Milli-Q grau de água cada. O tampão de lavagem pode ser preparado antecipadamente. </li><li> Remova cuidadosamente a lamela e junta de cada câmara microarray amplificação usando uma pinça de ponta plana. Esta etapa é o ponto em que há o maior risco de danos físicos matrizes elemento gel. Use os controles de contaminação PCR adequados para evitar a propagação de ácidos nucleicos amplificados dentro do ambiente de trabalho. </li><li> Coloque substratos microarray em um suporte de histologia slide, e coloque todos os slides para o caixote de lavagem contendo o tampão de lavagem. Cobrir o recipiente com uma tampa. </li><li> Lavar microarrays durante 10 min à temperatura ambiente com agitação suave. </li><li> Mergulhe os microarrays três vezes cada em duas lavagens sucessivas de deionizada ouA água de grau Milli-Q, e o ar seco. </li></ol> 5. Imagem A mistura de iniciadores MDR-TB assimétrica gera amplicons Cy3 marcado. Microarrays elemento Gel pode ser trabalhada com qualquer imager microarray padrão capaz de Cy3 imagem. O procedimento de imagem seguinte é específica para a mistura de MDR-TB mestre, campo Dx2100 imager portátil, e software de análise automatizado fornecida por Akonni. <ol><li> Verifique se o cabo ethernet do imager é conectado ao computador. </li><li> Ligue o gerador de imagens. O interruptor de alimentação está localizado no painel traseiro do instrumento. LEDs azuis na frente do sensor de imagem acende quando imager é ligado. </li><li> Ligue o computador. </li><li> Na área de trabalho do computador, clique duas vezes no ícone do software para o lançamento do software automatizado de análise de imagem. </li><li> Aguarde até que o software para estabelecer uma conexão com a câmera imager. Uma vez que a conexão é estabelecida, o botão Analisar se torna disponível, eomensagem &quot;Conexão bem sucedida&quot; aparecerá no canto inferior esquerdo da tela. </li><li> Insira o microarray amplificação seco com o microarray de costas para o usuário, e para a lente objetiva. Se o microarray é impropriamente orientadas em relação à lente e da câmara, o software de análise automatizado falhará para colocar uma grade sobre a imagem de fluorescência. </li><li> Feche a porta de acesso. Uma imagem de visualização estará disponível na tela do computador. </li><li> Selecione o script análise MDR-TB a partir do menu drop-down e digite o tempo de exposição desejado (em milisegundos). Um ponto de partida típico para elementos gel microarrays de amplificação é 100-500 ms. </li><li> Pixels saturados será exibido na Imagem em vermelho. Ajustar o tempo de exposição para minimizar o número de pixels saturados dentro pontos individuais. </li><li> Clique em Analisar para adquirir e analisar a imagem de fluorescência. O software irá automaticamente colocar umGrade específica do ensaio MDR-TB na imagem, extraia intensidade integrada e valores de fundo, e relatar os resultados de resistência a medicamentos e genotipagem. A análise automatizada normalmente demorar alguns segundos. Para imagens desafiadoras que contêm arranhões, poeira, artefatos fluorescentes ou dano físico às características de microarray, o software pode precisar de até 1 min para completar a análise. </li><li> Quando a análise estiver concluída, clique em Salvar, selecione a pasta de destino, digite um nome de arquivo e clique em OK. Dados de microarrays subjacentes são salvos como um arquivo xls. E podem ser exportados para o off-line analisa, se desejar. </li><li> Quando a análise estiver concluída, remova o microarray amplificação do sensor, e clique em Novo para iniciar a próxima análise. </li><li> Quando terminar a coleta de dados, feche o software, desligar o computador e desligue o gerador de imagens. </li></ol>

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K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-volatile+copolymer+compositions+for+fabricating+gel+element+microarrays.">Non-volatile copolymer compositions for fabricating gel element microarrays.</a> Anal. Biochem. 421, 526-533 (2012).</li><li>Cooney, C. G., Sipes, D., Thakore, N., Holmberg, R., Belgrader, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+plastic,+disposable+microfluidic+flow+cell+for+coupled+on-chip+PCR+and+microarray+detection+of+infectious+agents.">A plastic, disposable microfluidic flow cell for coupled on-chip PCR and microarray detection of infectious agents.</a> Biomed. Microdevices. 14, 45-53 (2012).</li><li>Lane, S., Evermann, J., Loge, F., Call, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amplicon+secondary+structure+prevents+target+hybridization+to+oligonucleotide+microarrays.">Amplicon secondary structure prevents target hybridization to oligonucleotide microarrays.</a> Biosens. Bioelectron. 20, 728-735 (2004).</li><li>El-Hajj, H. H., Marras, S. A. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+sloppy+molecular+beacon+probes+for+identification+of+Mycobacterial+species.">Use of sloppy molecular beacon probes for identification of Mycobacterial species.</a> J. Clin. Microbiol. 47, 1190-1198 (2009).</li><li>Boehme, C. C., Nabeta, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+molecular+detection+of+tuberculosis+and+rifampin+resistance.">Rapid molecular detection of tuberculosis and rifampin resistance.</a> N. Engl. J. Med. 363, 1005-1015 (2010).</li></ol>

Os autores declaram não haver interesses financeiros concorrentes.

O grau de multiplexagem, com um microarray de amplificação é, em última análise ditada pela eficácia do multiplex PCR assimétrica, não o microarray. Em nossa experiência, 10-12 pares de primers exclusivos podem ser facilmente multiplexados em um formato amplificação microarray. Critérios de primers e sonda de design convencionais, portanto, aplicar-se a novos testes, a não ser que a pessoa também precisa considerar possíveis interações entre os ácidos nucléicos em fase de solução e sondas de microar...

Detecção precoce de casos e tratamento rápido são consideradas as estratégias de controle mais eficazes para reduzir o Mycobacterium tuberculosis (MTB) Transmissão 1, e agora há um amplo consenso na comunidade TB que um ponto de atendimento (POC) ou próximo teste POC para diagnosticar simultaneamente TB e resistência a drogas (DR) é necessária. Tecnologias como GeneXpert de Cepheid e outros testes de amplificação de ácidos nucleicos reduzir o tempo de diagnóstico para muitos pacientes com TB, e proporcionar uma leitura rápida, indicando resistência à rifampicina ou mutações que conferem resistência selecionados para outros de primeira ou segunda linha de medicamentos 2. Embora ensaios de amplificação em tempo real e de ácidos nucleicos isotérmica são concebidos para identificar as mutações de resistência a drogas que levam a MDR-TB, o espectro de mutações que detectam é muitas vezes inadequada para conceber um regime de droga individualizada correspondente ao perfil de resistência a drogas do paciente, e as restrições técnicas relacionadasde cross-talk óptico ou a complexidade da amplificação e relatórios químicos 03-07 maio limitar o número de loci ou mutações que são detectados. Assim, tecnologias de detecção com maior capacidade de multiplexação são necessárias para suprir as lacunas conhecidas em diagnósticos POC MDR-TB. Microarrays e Hain ensaios sonda linha OMS endossadas pode resolver o &quot;gene múltiplo, mutações&quot; desafio de diagnosticar MDR-TB 8-29. Infelizmente, estes, plataformas de detecção multiplexados baseada hibridização usar várias etapas, complicado, e protocolos de amplicon aberto que exigem treinamento e proficiência significativo em técnicas moleculares. O microarray amplificação 30 foi projetado para atender algumas dessas preocupações operacionais microarray work-flow e. Os princípios fluídicos simplificadoras são para amplificar, hibridizar e detectar alvos de ácido nucléico em uma única câmara microfluídicos. O usuário introduz os ácidos nucléicos e amplificação master misturar em uma câmara de fluidos, com uma pipeta e inicia o protocolo de ciclos térmicos. Para o método de processamento do lote mostrado aqui, microarrays são subsequentemente lavadas em solução a granel, seca e fotografada. Este estudo demonstra a funcionalidade de um microarray de amplificação, utilizando um teste de MDR-TB microarray para rpoB (30 mutações), KatG (2 mutações), inhA (4 mutações), rpsL (2 mutações), embB (1 mutação), IS1245, IS6110 , e uma amplificação interna e controlo de hibridação. Pelo menos um par correspondente de sondas de microarray (de tipo selvagem (WT) e mutantes de um único nucleótido (MU)) é incluído para cada mutação de interesse. Ácidos nucleicos purificados de M. multirresistente tuberculose são do Strain TDR Tuberculose Banco 31. Microarrays elemento Gel são fabricados em substratos de vidro por copolimerização essencialmente como descrito em outra parte 32, só que usamos 4% e 0,05 mM monômero cada sonda no polymerizmistura ção. As matrizes são rodeados por uma junta de 50 ml, antes da utilização. Depois de ciclos térmicos, hibridação, lavagem e passos, microarrays de amplificação são gravadas em um analisador portátil Akonni. Correção de fundo, intensidades de sinal integrados são obtidos a partir da matéria. Imagens tif usando um algoritmo círculo fixo. Ruído para cada elemento de gel é calculado como três vezes o desvio padrão da mancha de fundo locais. Genes alvos são normalmente considerados detectável por sinal-ruído (SNR) de valores ≥ 3. A fim de determinar a presença ou ausência de uma mutação específica no gene ou cada codão, um rácio discriminante é calculado a partir dos valores de SNR como (WT-MU) / (TP + MU). Rácios discriminantes &lt;0 são indicativos de uma mutação de resistência a drogas no local, enquanto que os rácios&gt; 0 são indicativos da sequência de tipo selvagem.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;">MDR-TB amplification microarrays, with applied gasket and pre-cut cover slips</td>
			<td>Akonni Biosystems</td>
			<td>Inquire</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Multiplex PCR kit, containing 2X PCR buffer with HotStar Taq plus</td>
			<td>Qiagen</td>
			<td>#206143</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Taq polymerase</td>
			<td>Qiagen</td>
			<td>#201207</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">RNAse-free water</td>
			<td>Qiagen</td>
			<td>#206143&#160;</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Formamide</td>
			<td>Thermo Fisher Scientific, Inc.</td>
			<td>#BP227-500</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">20 mg mL-1 non-acetlyated bovine serum albumin (BSA)</td>
			<td>Sigma-Aldrich</td>
			<td>#3B6917</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">5X concentrated MDR-TB primer mix</td>
			<td>Akonni Biosystems</td>
			<td>Inquire</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">500 fg uL-1 amplification and inhibition control</td>
			<td>Akonni Biosystems</td>
			<td>Inquire</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">20X SSPE</td>
			<td>Thermo Fisher Scientific, Inc.</td>
			<td>#BP1328-4</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Triton X-100</td>
			<td>Thermo Fisher Scientific, Inc.</td>
			<td>#BP151-500</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Disinfecting Spray&#160;</td>
			<td>Current Technologies, Inc.</td>
			<td>#BRSPRAY128</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">70% Isopropyl Alcohol</td>
			<td>Decon Labs, Inc.</td>
			<td>#8416</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Equipment</td>
			<td>Company&#160;</td>
			<td>Catalog Number&#160;</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Microarray imager, with automated image and data analysis software</td>
			<td>Akonni Biosystems</td>
			<td>100-20011</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Thermal cycler with flat block insert</td>
			<td>Akonni Biosystems</td>
			<td>100-10021</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">High-throughput wash station and slide holder</td>
			<td>ArrayIt</td>
			<td>HTW</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Dissecting forceps</td>
			<td>Thermo Fisher Scientific, Inc.</td>
			<td>#10-300</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Mini Vortexer</td>
			<td>VWR</td>
			<td>#3365040</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Mini-centrifuge</td>
			<td>VWR</td>
			<td>#93000-196</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">Airbrush Compressor Kit</td>
			<td>Central Pneumatic</td>
			<td>#95630</td>
			<td></td>
		</tr>
	</tbody>
</table>

demonstrating a multi-drug resistant mycobacterium tuberculosis amplification microarray

Simplificar o fluxo de trabalho microarray é um primeiro passo necessário para a criação de MDR-TB diagnósticos baseados em microarray que podem ser rotineiramente usados ​​em ambientes com recursos mais baixos. Um microarray amplificação combina amplificação PCR assimétrico, a seleção tamanho do alvo, rotulagem alvo, e hibridização microarray dentro de uma única solução e em uma única câmara microfluídicos. Um método de processamento em lote é demonstrada com uma mistura mestre assimétrica 9-plex e baixa densidade elemento gel microarray para a genotipagem da multi-droga resistente Mycobacterium tuberculosis (MDR-TB). O protocolo aqui descrito pode ser concluída em 6 horas e fornecer genotipagem correcta com, pelo menos, 1.000 equivalentes de células de ADN genómico. A incorporação no chip passos de lavagem é possível, o que irá resultar num método amplicão totalmente fechada e sistema. O grau de multiplexagem, com um microarray de amplificação é relacionada ao número de pares de iniciadores que podem ser combinados num único mestre mix e ainda atingir a sensibilidade desejada e as métricas de desempenho especificidade, em vez do número de sondas que são imobilizados na matriz. Do mesmo modo, o tempo total de análise pode ser reduzido ou aumentado, dependendo do uso específico a que se destinam, questão de pesquisa, e limites desejados de detecção. No entanto, a abordagem geral agiliza significativamente o fluxo de trabalho microarray para o usuário final, reduzindo o número de etapas de processamento manualmente intensivos e demorados, e fornece um caminho bioquímico e microfluídicos simplificado para traduzir diagnósticos baseados em microarrays para a prática clínica de rotina.

Análise de imagem qualitativa pode fornecer informações sobre as fontes de ruído experimental ou variabilidade que são difíceis de identificar em tabelas de dados gerados pelo software automatizado de análise de imagem. Assim, ele pode ser útil para determinar visualmente que 1) todos os elementos de gel estão intactos e não danificado, 2) o fundo global é livre de artefactos fluorescentes que podem afectar o sinal individual de valores de ruído (SNR), 3), não há evidência de formação de bolhas ou não ...

Watch this Scientific Journal Video about Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray at JoVE.com

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

Um microarray amplificação combina assimétrica PCR amplificação e hibridização microarray em uma única câmara, que simplifica significativamente o fluxo de trabalho microarray para o usuário final. Simplificar o fluxo de trabalho microarray é um primeiro passo necessário para a criação de diagnósticos à base de microarray que podem ser rotineiramente usados ​​em ambientes com recursos mais baixos.

Demonstrando um multi-resistente<em&gt; Mycobacterium tuberculosis</em&gt; Ampliação Microarray

Simplifying microarray workflow is a necessary first step for creating MDR-TB microarray-based diagnostics that can be routinely used in lower-resource ...

demonstrating-multi-drug-resistant-mycobacterium-tuberculosis

Research

JoVE Journal

Immunology and Infection

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

12.5K visualizações.  Akonni Biosystems, Inc..  Um microarray amplificação combina assimétrica PCR amplificação e hibridização microarray em uma única câmara, que simplifica significativamente o fluxo de trabalho microarray para o usuário final. Simplificar o fluxo de trabalho microarray é um primeiro passo necessário para a criação de diagnósticos à base de microarray que podem ser rotineiramente usados ​​em ambientes com recursos mais baixos. 

Vídeo: Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

Antimicrobial Susceptibility Testing of Mycobacterium Tuberculosis Complex for First and Second Line Drugs by Broth Dilution in a Microtiter Plate Format

The rapid detection of antimicrobial resistance is important in the effort to control the increase in resistant Mycobacterium 
tuberculosis (Mtb). Antimicrobial susceptibility testing (AST) of Mtb has traditionally been performed by the agar method of proportion or by 
macrobroth testing on an instrument such as the BACTEC (Becton Dickinson, Sparks, MD), VersaTREK (TREK Diagnostics, Cleveland, OH) or BacT/ALERT (bioM&eacute;rieux, Hazelwood, MO). The agar proportion method, while considered the &#x201C;gold&#x201D; standard of AST, is labor intensive and requires calculation of resistance by performing colony counts on drug-containing agar as compared to drug-free agar. If there is &ge;1% growth on the drug-containing medium as compared to drug-free medium, the organism is considered resistant to that drug. The macrobroth methods require instrumentation and test break point ("critical") drug concentrations for the first line drugs (isoniazid, ethambutol, rifampin, and pyrazinamide). The method described here is commercially available in a 96 well microtiter plate format [MYCOTB (TREK Diagnostics)] and contains increasing concentrations of 12 antimicrobials used for treatment of tuberculosis including both first (isoniazid, rifampin, ethambutol) and second line drugs (amikacin, cycloserine, ethionamide, kanamycin, moxifloxacin, ofloxacin, para-aminosalicylic acid, rifabutin, and streptomycin). Pyrazinamide, a first line drug, is not included in the microtiter plate due to its need for acidic test conditions. Advantages of the microtiter system include both ease of set up and faster turn around time (14 days) compared with traditional agar proportion (21 days). In addition, the plate can be set up from inoculum prepared using either broth or solid medium. Since the microtiter plate format is new and since Mtb presents unique safety challenges in the laboratory, this protocol will describe how to safely setup, incubate and read the microtiter plate.

Antimicrobial susceptibility testing of Mycobacterium tuberculosis is challenging but critical for patient care. This microtiter plate format offers testing of 12 antimycobacterial drugs and provides minimum inhibitory concentration (MIC) values, which will aid in appropriate treatment.

Teste de susceptibilidade antimicrobiana do complexo Mycobacterium tuberculosis da Droga primeira e segunda linha de diluição em caldo em um formato de placa de microtitulação

The rapid detection of antimicrobial resistance is important in the effort to control the increase in resistant Mycobacterium 
tuberculosis (Mtb). ...

Imunologia e Infecção

Sample Preparation of Mycobacterium tuberculosis Extracts for Nuclear Magnetic Resonance Metabolomic Studies

Mycobacterium tuberculosis is a major cause of mortality in human beings on a global scale. The emergence of both multi- (MDR) and extensively-(XDR) drug-resistant strains threatens to derail current disease control efforts. Thus, there is an urgent need to develop drugs and vaccines that are more effective than those currently available. The genome of M. tuberculosis has been known for more than 10 years, yet there are important gaps in our knowledge of gene function and essentiality. Many studies have since used gene expression analysis at both the transcriptomic and proteomic levels to determine the effects of drugs, oxidants, and growth conditions on the global patterns of gene expression. Ultimately, the final response of these changes is reflected in the metabolic composition of the bacterium including a few thousand small molecular weight chemicals. Comparing the metabolic profiles of wild type and mutant strains, either untreated or treated with a particular drug, can effectively allow target identification and may lead to the development of novel inhibitors with anti-tubercular activity. Likewise, the effects of two or more conditions on the metabolome can also be assessed. Nuclear magnetic resonance (NMR) is a powerful technology that is used to identify and quantify metabolic intermediates. In this protocol, procedures for the preparation of M. tuberculosis cell extracts for NMR metabolomic analysis are described. Cell cultures are grown under appropriate conditions and required Biosafety Level 3 containment,1 harvested, and subjected to mechanical lysis while maintaining cold temperatures to maximize preservation of metabolites. Cell lysates are recovered, filtered sterilized, and stored at ultra-low temperatures. Aliquots from these cell extracts are plated on Middlebrook 7H9 agar for colony-forming units to verify absence of viable cells. Upon two months of incubation at 37 &deg;C, if no viable colonies are observed, samples are removed from the containment facility for downstream processing. Extracts are lyophilized, resuspended in deuterated buffer and injected in the NMR instrument, capturing spectroscopic data that is then subjected to statistical analysis. The procedures described can be applied for both one-dimensional (1D) 1H NMR and two-dimensional (2D) 1H-13C NMR analyses. This methodology provides more reliable small molecular weight metabolite identification and more reliable and sensitive quantitative analyses of cell extract metabolic compositions than chromatographic methods. Variations of the procedure described following the cell lysis step can also be adapted for parallel proteomic analysis.

Sample Preparation of Mycobacterium tuberculosis Extracts for Nuclear Magnetic Resonance Metabolomic Studies

The metabolomic profile of Mycobacterium tuberculosis is determined after growth in broth cultures. Conditions can be varied to test the effects of nutritional supplements, oxidants, and anti-tuberculosis agents on the metabolic profile of this microorganism. Procedure for extract preparation is applicable for both 1D 1H and 2D 1H-13C NMR analyses.

Preparação de amostras de<em&gt; Mycobacterium tuberculosis</em&gt; Extractos para Estudos Nucleares metabolômica Ressonância Magnética

Mycobacterium tuberculosis is a major cause of mortality in human beings on a global scale. The emergence of both multi- (MDR) and extensively-(XDR) ...

Growth of Mycobacterium tuberculosis Biofilms

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, has an extraordinary ability to survive against environmental stresses including antibiotics. Although stress tolerance of M. tuberculosis is one of the likely contributors to the 6-month long chemotherapy of tuberculosis 1, the molecular mechanisms underlying this characteristic phenotype of the pathogen remain unclear. Many microbial species have evolved to survive in stressful environments by self-assembling in highly organized, surface attached, and matrix encapsulated structures called biofilms 2-4. Growth in communities appears to be a preferred survival strategy of microbes, and is achieved through genetic components that regulate surface attachment, intercellular communications, and synthesis of extracellular polymeric substances (EPS) 5,6. The tolerance to environmental stress is likely facilitated by EPS, and perhaps by the physiological adaptation of individual bacilli to heterogeneous microenvironments within the complex architecture of biofilms 7.
In a series of recent papers we established that M. tuberculosis and Mycobacterium smegmatis have a strong propensity to grow in organized multicellular structures, called biofilms, which can tolerate more than 50 times the minimal inhibitory concentrations of the anti-tuberculosis drugs isoniazid and rifampicin 8-10. M. tuberculosis, however, intriguingly requires specific conditions to form mature biofilms, in particular 9:1 ratio of headspace: media as well as limited exchange of air with the atmosphere 9. Requirements of specialized environmental conditions could possibly be linked to the fact that M. tuberculosis is an obligate human pathogen and thus has adapted to tissue environments. In this publication we demonstrate methods for culturing M. tuberculosis biofilms in a bottle and a 12-well plate format, which is convenient for bacteriological as well as genetic studies. We have described the protocol for an attenuated strain of M. tuberculosis, mc27000, with deletion in the two loci, panCD and RD1, that are critical for in vivo growth of the pathogen 9. This strain can be safely used in a BSL-2 containment for understanding the basic biology of the tuberculosis pathogen thus avoiding the requirement of an expensive BSL-3 facility. The method can be extended, with appropriate modification in media, to grow biofilm of other culturable mycobacterial species.
Overall, a uniform protocol of culturing mycobacterial biofilms will help the investigators interested in studying the basic resilient characteristics of mycobacteria. In addition, a clear and concise method of growing mycobacterial biofilms will also help the clinical and pharmaceutical investigators to test the efficacy of a potential drug.

Growth of Mycobacterium tuberculosis Biofilms

Mycobacterium tuberculosis forms drug tolerant biofilms when cultured in certain conditions. Here we describe methods for culturing M. tuberculosis biofilms and determining the frequency of drug tolerant persisters. These protocols will be useful for further studies into the mechanisms of drug tolerance in M. tuberculosis.

Crescimento de Mycobacterium tuberculosis Biofilmes

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, has an extraordinary ability to survive against environmental stresses including ...

Protein Misfolding Cyclic Amplification of Prions

Prions are infectious agents that cause the inevitably fatal transmissible spongiform encephalopathy (TSE) in animals and humans9,18. The prion protein has two distinct isoforms, the non-infectious host-encoded protein (PrPC) and the infectious protein (PrPSc), an abnormally-folded isoform of PrPC 8.
One of the challenges of working with prion agents is the long incubation period prior to the development of clinical signs following host inoculation13. This traditionally mandated long and expensive animal bioassay studies. Furthermore, the biochemical and biophysical properties of PrPSc are poorly characterized due to their unusual conformation and aggregation states.
PrPSc can seed the conversion of PrPC to PrPSc in vitro14. PMCA is an in vitro technique that takes advantage of this ability using sonication and incubation cycles to produce large amounts of PrPSc, at an accelerated rate, from a system containing excess amounts of PrPC and minute amounts of the PrPSc seed19. This technique has proven to effectively recapitulate the species and strain specificity of PrPSc conversion from PrPC, to emulate prion strain interference, and to amplify very low levels of PrPSc from infected tissues, fluids, and environmental samples6,7,16,23 .
This paper details the PMCA protocol, including recommendations for minimizing contamination, generating consistent results, and quantifying those results. We also discuss several PMCA applications, including generation and characterization of infectious prion strains, prion strain interference, and the detection of prions in the environment.

Protein misfolding cyclic amplification (PMCA) is an in vitro assay for the study of prion conversion and strain and species barriers. It can also be used as a prion detection assay.

Proteína amplificação cíclica misfolding de príons

Prions  are infectious agents that cause the inevitably fatal transmissible spongiform  encephalopathy (TSE) in animals and humans9,18. The prion protein ...

An Experimental Model to Study Tuberculosis-Malaria Coinfection upon Natural Transmission of Mycobacterium tuberculosis and Plasmodium berghei

Coinfections naturally occur due to the geographic overlap of distinct types of pathogenic organisms. Concurrent infections most likely modulate the respective immune response to each single pathogen and may thereby affect pathogenesis and disease outcome. Coinfected patients may also respond differentially to anti-infective interventions. Coinfection between tuberculosis as caused by mycobacteria and the malaria parasite Plasmodium, both of which are coendemic in many parts of sub-Saharan Africa, has not been studied in detail. In order to approach the challenging but scientifically and clinically highly relevant question how malaria-tuberculosis coinfection modulate host immunity and the course of each disease, we established an experimental mouse model that allows us to dissect the elicited immune responses to both pathogens in the coinfected host. Of note, in order to most precisely mimic naturally acquired human infections, we perform experimental infections of mice with both pathogens by their natural routes of infection, i.e. aerosol and mosquito bite, respectively.

An Experimental Model to Study Tuberculosis-Malaria Coinfection upon Natural Transmission of Mycobacterium tuberculosis and Plasmodium berghei

Tuberculosis and malaria are two of the most prevalent infections in humans and major causes of morbidity and mortality in impoverished populations in the tropics. We established an experimental model system to study outcome of malaria-tuberculosis coinfection in mice after challenge with both pathogens via their natural route of infection.

Um modelo experimental para estudar a Tuberculose-Malária Coinfection sobre Transmissão Natural de Mycobacterium tuberculosis E Plasmodium berghei</i

Coinfections naturally occur due to the geographic overlap of distinct types of pathogenic organisms. Concurrent infections most likely modulate the ...

A Novel Microdissection Approach to Recovering Mycobacterium tuberculosis Specific Transcripts from Formalin Fixed Paraffin Embedded Lung Granulomas

Microdissection has been used for the examination of tissues at DNA, RNA, and protein levels for over a decade. Laser capture microscopy (LCM) is the most common microdissection technique used today. In this technique, a laser is used to focally melt a thermoplastic membrane that overlies a dehydrated tissue section1. The tissue section composite is then lifted and separated from the membrane. Although this technique can be used successfully for tissue examination, it is time consuming and expensive. Furthermore, the successful completion of procedures using this technique requires the use of a laser, thus limiting its use. A new more affordable and practical microdissection approach called mesodissection is a possible solution to the pitfalls of LCM. This technique employs the MESO-1/MeSectr system to mill the desired tissue from a slide mounted tissue sample while concurrently dispensing and aspirating fluid to recover the desired tissue sample into a consumable mill bit. Before the dissection process begins, the user aligns the formalin fixed paraffin embedded (FFPE) slide with a hematoxylin and eosin stained (H&#38;E) reference slide. Thereafter, the operator annotates the desired dissection area and proceeds to dissect the appropriate segment. The program generates an archived image of the dissection. The main advantage of mesodissection is the short duration needed to dissect a slide, taking an average of ten minutes from set up to sample generation in this experiment. Additionally, the system is significantly more cost effective and user friendly. A slight disadvantage is that it is not as precise as laser capture microscopy. In this article we demonstrate how mesodissection can be used to extract RNA from slides from FFPE granulomas caused by Mycobacterium tuberculosis (Mtb).

A Novel Microdissection Approach to Recovering Mycobacterium tuberculosis Specific Transcripts from Formalin Fixed Paraffin Embedded Lung Granulomas

Microdissection has been extensively employed for the examination of DNA, RNA, and protein within tissue. Laser capture microscopy (LCM) is the most commonly used method, but a new milling technique, mesodissection, is recently available. We demonstrate RNA extraction from mesodissected formalin fixed paraffin embedded tissue slides of Mycobacterium tuberculosis granulomas.

Uma nova abordagem para Microdissecção Recuperando<em&gt; Mycobacterium tuberculosis</em&gt; transcritos específicos de formalina fixo Parafina incorporado Lung granulomas

Microdissection has been used for the examination of tissues at DNA, RNA, and protein levels for over a decade. Laser capture microscopy (LCM) is the most ...

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Human tuberculosis infection is a complex process, which is difficult to model in vitro. Here we describe a novel 3D human lung tissue model that recapitulates the dynamics that occur during infection, including the migration of immune cells and early granuloma formation in a physiological environment.

Um modelo de tecido Pulmão humano 3D para estudos funcionais em<em&gt; Mycobacterium tuberculosis</em&gt; Infecção

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us ...

System for Efficacy and Cytotoxicity Screening of Inhibitors Targeting Intracellular Mycobacterium tuberculosis

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is a leading cause of morbidity and mortality worldwide. With the increased spread of multi drug-resistant TB (MDR-TB), there is a real urgency to develop new therapeutic strategies against M. tuberculosis infections. Traditionally, compounds are evaluated based on their antibacterial activity under in vitro growth conditions in broth; however, results are often misleading for intracellular pathogens like M. tuberculosis since in-broth phenotypic screening conditions are significantly different from the actual disease conditions within the human body. Screening for inhibitors that work inside macrophages has been traditionally difficult due to the complexity, variability in infection, and slow replication rate of M. tuberculosis. In this study, we report a new approach to rapidly assess the effectiveness of compounds on the viability of M. tuberculosis in a macrophage infection model. Using a combination of a cytotoxicity assay and an in-broth M. tuberculosis viability assay, we were able to create a screening system that generates a comprehensive analysis of compounds of interest. This system is capable of producing quantitative data at a low cost that is within reach of most labs and yet is highly scalable to fit large industrial settings.

System for Efficacy and Cytotoxicity Screening of Inhibitors Targeting Intracellular Mycobacterium tuberculosis

We have developed a modular high-throughput screening system for discovering novel compounds against Mycobacterium tuberculosis, targeting intracellular and in-broth growing bacteria as well as cytotoxicity against the mammalian host cell.

Sistema de Eficácia e citotoxicidade Rastreio de inibidores Segmentação intracelular<em&gt; Mycobacterium tuberculosis</em

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is a leading cause of morbidity and mortality worldwide. With the increased spread ...

A High-throughput Compatible Assay to Evaluate Drug Efficacy against Macrophage Passaged Mycobacterium tuberculosis

The early drug development process for anti-tuberculosis drugs is hindered by the inefficient translation of compounds with in vitro activity to effectiveness in the clinical setting. This is likely due to a lack of consideration for the physiologically relevant cellular penetration barriers that exist in the infected host. We recently established an alternative infection model that generates large macrophage aggregate structures containing densely packed M. tuberculosis (Mtb) at its core, which was suitable for drug susceptibility testing. This infection model is inexpensive, rapid, and most importantly BSL-2 compatible. Here, we describe the experimental procedures to generate Mtb/macrophage aggregate structures that would produce macrophage-passaged Mtb for drug susceptibility testing. In particular, we demonstrate how this infection system could be directly adapted to the 96-well plate format showing throughput capability for the screening of compound libraries against Mtb. Overall, this assay is a valuable addition to the currently available Mtb drug discovery toolbox due to its simplicity, cost effectiveness, and scalability.

A High-throughput Compatible Assay to Evaluate Drug Efficacy against Macrophage Passaged Mycobacterium tuberculosis

New models and assays that would improve the early drug development process for next-generation anti-tuberculosis drugs are highly desirable. Here, we describe a quick, inexpensive, and BSL-2 compatible assay to evaluate drug efficacy against Mycobacterium tuberculosis that can be easily adapted for high-throughput screening.

Um ensaio Compatível de alta capacidade para avaliar droga Eficácia contra macrófagos passadas<em&gt; Mycobacterium tuberculosis</em

The early drug development process for anti-tuberculosis drugs is hindered by the inefficient translation of compounds with in vitro activity to ...

Analysis of 18FDG PET/CT Imaging as a Tool for Studying Mycobacterium tuberculosis Infection and Treatment in Non-human Primates

Mycobacterium tuberculosis remains the number one infectious agent in the world today. With the emergence of antibiotic resistant strains, new clinically relevant methods are needed that evaluate the disease process and screen for potential antibiotic and vaccine treatments. Positron Emission Tomography/Computed Tomography (PET/CT) has been established as a valuable tool for studying a number of afflictions such as cancer, Alzheimer&#39;s disease, and inflammation/infection. Outlined here are a number of strategies that have been employed to evaluate PET/CT images in cynomolgus macaques that are infected intrabronchially with low doses of M. tuberculosis. Through evaluation of lesion size on CT and uptake of 18F-fluorodeoxyglucose (FDG) in lesions and lymph nodes in PET images, these described methods show that PET/CT imaging can predict future development of active versus latent disease and the propensity for reactivation from a latent state of infection. Additionally, by analyzing the overall level of lung inflammation, these methods determine antibiotic efficacy of drugs against M. tuberculosis in the most clinically relevant existing animal model. These image analysis methods are some of the most powerful tools in the arsenal against this disease as not only can they evaluate a number of characteristics of infection and drug treatment, but they are also directly translatable to a clinical setting for use in human studies.

Analysis of 18FDG PET/CT Imaging as a Tool for Studying Mycobacterium tuberculosis Infection and Treatment in Non-human Primates

Here, we present a protocol to describe the analysis of 18F-FDG PET/CT imaging in non-human primates that have been infected with M. tuberculosis to study disease process, drug treatment, and disease reactivation.

Análise de 18FDG PET-CT Imaging como uma ferramenta para estudar infecção por Mycobacterium tuberculosis e tratamento em primatas não-humanos

Mycobacterium tuberculosis remains the number one infectious agent in the world today. With the emergence of antibiotic resistant strains, new clinically ...