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Aplicação de sistemas moleculares na detecção rápida de MDR-TB e XDR-TB
| Nome: | Descrição: | Tamanho: | Formato: | |
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| Dissertação de Mestrado | 3.42 MB | Adobe PDF |
Orientador(es)
Resumo(s)
Mycobacterium tuberculosis é o agente etiológico da tuberculose em humanos e segundo as estimativas da Organização Mundial da Saúde, um terço da população mundial está infectada com esta bactéria, calculando-se que no ano de 2008 aproximadamente 9,4 milhões de pessoas contraíram tuberculose activa. Associada a esta tendência, encontra-se o aumento alarmante da incidência de tuberculose resistente aos antibióticos, mais propriamente da tuberculose multirresistente e extensivamente resistente.
Nesta Dissertação estudaram-se três sistemas de detecção molecular (INNO-LiPA Rif. TB, Innogenetics, Ghent, Bélgica, MTBDRplus e MTBDRsl, GenoType, GmbH, Nehren, Alemanha), que permitem detectar o complexo M. tuberculosis e as mutações mais comuns associadas à resistência aos antibióticos de primeira e segunda linha. Para o efeito, na primeira parte do trabalho os três sistemas em estudo foram testados em 21 isolados clínicos pertencentes à colecção do Laboratório de Micobactérias do Instituto de Higiene e Medicina Tropical (IHMT, UNL), com o propósito de avaliar a sua capacidade para identificar o complexo M. tuberculosis e detectar mutações ligadas à resistência aos fármacos de primeira e segunda linha. Na segunda parte do trabalho, os sistemas INNO-LiPA Rif. TB e MTBDRplus foram testados em 33 amostras respiratórias com baciloscopia positiva, com o propósito de aferir a “performance” destes sistemas para a detecção directa de tuberculose multirresistente em amostras respiratórias.
Na primeira parte do trabalho os três sistemas em estudo apresentaram elevada sensibilidade na identificação do complexo M. tuberculosis em culturas, bem como na detecção de mutações ligadas à resistência aos antibióticos de primeira linha, com excepção do etambutol. No que diz respeito à detecção da resistência aos antibióticos de segunda linha, não foi possível calcular os valores de sensibilidade e especificidade.
Na segunda parte do trabalho, o INNO-LiPA Rif. TB demonstrou ser o sistema mais robusto para a análise directa de amostras respiratórias com baciloscopia positiva, para um diagnóstico precoce de tuberculose e detecção de resistência à rifampicina. O MTBDRplus não se mostrou uma alternativa viável ao INNO-LiPA Rif. TB, pois apresentou baixa sensibilidade para a identificação do complexo M. tuberculosis e vários problemas no passo de amplificação. O MTBDRsl não foi testado, por não ter sido detectada nenhuma amostra multirresistente.
Mycobacterium tuberculosis is the etiologic agent of tuberculosis in humans and, according to the World Health Organization, one-third of the world’s population is infects with this bacteria, with an estimated 9.4 million incident cases of tuberculosis globally in 2008. Associated with this alarming trend is a frightening increase in the incidence of M. tuberculosis resistant to antibiotics, more specifically multidrug-resistant tuberculosis and extremely drug-resistant tuberculosis. In this Thesis, we studied three molecular detection systems (INNO-LiPA Rif. TB, Innogenetics, MTBDRplus and MTBDRsl, GenoType), which allow the molecular identification of the M. tuberculosis complex and the detection of mutations most often associated with antibiotic resistance. In the first phase of the work the three systems were tested in 21 clinical isolates belonging to the collection of the Mycobacteria Laboratory of IHMT, UNL, with the aim to assess their ability for identifying the M. tuberculosis complex and to detect mutations related to the resistance to first and second line antibiotics. In the second stage of the study, the INNO-LiPA Rif. TB and the MTBDRplus were tested in acid-fast positive respiratory specimens, to assess their performance to detect directly M. tuberculosis and mutations related to rifampicin resistance in these specimens. In the first part of the work the three systems showed high sensitivity for the identification of the M. tuberculosis complex and for detection of resistance to first line antibiotics, except for ethambutol. Regarding the detection of resistance in second line antibiotics, we could not calculate the sensitivity and specificity. In the second part of the work the INNO-LiPA Rif. TB assay proved to be the system of choice for use directly in acid-fast positive respiratory specimens in the early diagnosis of tuberculosis and the detection of rifampicin resistance. The MTBDRplus was not a good alternative to the INNO-LiPA Rif. TB due to its low sensitivity in the identification of the M. tuberculosis complex and the occurrence of several problems in the amplification step. The MTBDRsl was not used because no multidrug resistant samples were detected.
Mycobacterium tuberculosis is the etiologic agent of tuberculosis in humans and, according to the World Health Organization, one-third of the world’s population is infects with this bacteria, with an estimated 9.4 million incident cases of tuberculosis globally in 2008. Associated with this alarming trend is a frightening increase in the incidence of M. tuberculosis resistant to antibiotics, more specifically multidrug-resistant tuberculosis and extremely drug-resistant tuberculosis. In this Thesis, we studied three molecular detection systems (INNO-LiPA Rif. TB, Innogenetics, MTBDRplus and MTBDRsl, GenoType), which allow the molecular identification of the M. tuberculosis complex and the detection of mutations most often associated with antibiotic resistance. In the first phase of the work the three systems were tested in 21 clinical isolates belonging to the collection of the Mycobacteria Laboratory of IHMT, UNL, with the aim to assess their ability for identifying the M. tuberculosis complex and to detect mutations related to the resistance to first and second line antibiotics. In the second stage of the study, the INNO-LiPA Rif. TB and the MTBDRplus were tested in acid-fast positive respiratory specimens, to assess their performance to detect directly M. tuberculosis and mutations related to rifampicin resistance in these specimens. In the first part of the work the three systems showed high sensitivity for the identification of the M. tuberculosis complex and for detection of resistance to first line antibiotics, except for ethambutol. Regarding the detection of resistance in second line antibiotics, we could not calculate the sensitivity and specificity. In the second part of the work the INNO-LiPA Rif. TB assay proved to be the system of choice for use directly in acid-fast positive respiratory specimens in the early diagnosis of tuberculosis and the detection of rifampicin resistance. The MTBDRplus was not a good alternative to the INNO-LiPA Rif. TB due to its low sensitivity in the identification of the M. tuberculosis complex and the occurrence of several problems in the amplification step. The MTBDRsl was not used because no multidrug resistant samples were detected.
Descrição
Palavras-chave
Ciências biomédicas Biologia molecular Micobactérias Mycobacterium tuberculosis Análise e diagnóstico
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical