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Nas últimas duas décadas tem-se verificado um aumento da incidência de aspergilose pulmonar invasiva, que se reflecte em taxas de mortalidade e morbilidade extremamente elevadas.
Esta realidade resulta da elevada utilização de quimioterapia e de agentes imunossupressores, usados sobretudo em doentes imunocomprometidos, principalmente, em doentes hemato-oncológicos e receptores de transplante de medula óssea.
Estas infecções fúngicas são provocadas por algumas espécies do género Aspergillus em que Aspergillus fumigatus é a espécie mais frequentemente isolada a partir de infecções humanas. Contudo, outras espécies como A. flavus, A. niger, A. glaucus, A. nidulans, A. terreus ou A. versicolor também podem ser responsáveis por infecções fúngicas no Homem.
Um factor determinante para o aumento da incidência de aspergilose invasiva consiste na incapacidade de se estabelecer um diagnóstico precoce definitivo para que, em tempo útil, possa ser instituída terapêutica antifúngica que vá seguramente melhorar o prognóstico desses doentes.
Actualmente, as técnicas convencionais (microbiológicas e histológicas) têm servido como linhas de orientação para o diagnóstico definitivo de micoses. No entanto, como se tratam técnicas morosas, o diagnóstico imunológico e molecular tem todas as potencialidades para oferecer uma abordagem promissora no diagnóstico de infecções fúngicas.
Neste trabalho foram estudadas 37 amostras clínicas, das quais 45,9% pertenciam a indivíduos do sexo feminino, 54,1% do sexo masculino, maioritariamente com o diagnóstico clínico de leucemia mielóide aguda (75,7%).
O principal objectivo deste trabalho consistiu na comparação dos resultados obtidos por uma técnica imunológica utilizada no diagnóstico de aspergilose pulmonar invasiva (pesquisa do antigénio GM) com uma nova técnica molecular de diagnóstico (nested-PCR), com o intuito de avaliar a sensibilidade e especificidade dos resultados obtidos.
Dos 37 doentes do estudo, 35,1% revelaram presença do antigénio galactomanano e em 32,4% das amostras foi possível detectar DNA fúngico utilizando primers específicos numa reacção de nested-PCR. No final deste trabalho pode-se constatar que, em virtude do método molecular utilizando uma reacção de nested-PCR não se ter revelado mais sensível que a pesquisa do antigénio galactomanano, julgamos ser no entanto muito promissor no diagnóstico da aspergilose pulmonar invasiva, bastando apenas aperfeiçoar a sua optimização.
In the last two decades there has been an increase in incidence of invasive pulmonary aspergillosis, which is reflected in morbidity and mortality rates extremely high. This situation results from the use of high chemotherapy and immunosuppressive agents used especially in immunocompromised patients, especially in hemato-oncology patients and transplant recipients bone marrow. These fungal infections are caused by some species of the genus Aspergillus, where Aspergillus fumigatus is the species isolated more often from human infections. However, other species like A. flavus, A. niger, A. terreus, A. versicolor, A. nidulans and A. glaucus are also responsible for fungal infection in humans. A key factor in the increased incidence of invasive aspergillosis is the inability in establish an early definitive diagnosis so that in time can be applied an antifungal therapeutic, which will ensure the prognosis of these patients. Currently, the conventional techniques (microbiological and histological) were used as guide lines for the definitive diagnosis of mycoses. However, these are time-consuming techniques which make the immunologic and molecular diagnosis a promising approach in the fungal infection detection. In this work were studied 37 blood samples, 45.9% belonging to females, and 54.1% to males, mostly with the diagnosis clinical acute myeloid leukemia (75.7%). The main goal of this study was to compare an immunological technique (research GM antigen) with a new molecular diagnosis (nested-PCR), in order to evaluate which one offers more sensitive and specific outcomes. From the 37 patients in the study 35.1% revealed the presence of the galactomanan antigen, and in 32.4% of the samples was possible detect fungal DNA using specific primers in the nested-PCR reaction. At the end of this work can be found that, the molecular method did not reveal more sensitive than galactomannan antigen, although we believe to be very promising in the diagnosis of aspergillosis invasive pulmonary after improving its optimization.
In the last two decades there has been an increase in incidence of invasive pulmonary aspergillosis, which is reflected in morbidity and mortality rates extremely high. This situation results from the use of high chemotherapy and immunosuppressive agents used especially in immunocompromised patients, especially in hemato-oncology patients and transplant recipients bone marrow. These fungal infections are caused by some species of the genus Aspergillus, where Aspergillus fumigatus is the species isolated more often from human infections. However, other species like A. flavus, A. niger, A. terreus, A. versicolor, A. nidulans and A. glaucus are also responsible for fungal infection in humans. A key factor in the increased incidence of invasive aspergillosis is the inability in establish an early definitive diagnosis so that in time can be applied an antifungal therapeutic, which will ensure the prognosis of these patients. Currently, the conventional techniques (microbiological and histological) were used as guide lines for the definitive diagnosis of mycoses. However, these are time-consuming techniques which make the immunologic and molecular diagnosis a promising approach in the fungal infection detection. In this work were studied 37 blood samples, 45.9% belonging to females, and 54.1% to males, mostly with the diagnosis clinical acute myeloid leukemia (75.7%). The main goal of this study was to compare an immunological technique (research GM antigen) with a new molecular diagnosis (nested-PCR), in order to evaluate which one offers more sensitive and specific outcomes. From the 37 patients in the study 35.1% revealed the presence of the galactomanan antigen, and in 32.4% of the samples was possible detect fungal DNA using specific primers in the nested-PCR reaction. At the end of this work can be found that, the molecular method did not reveal more sensitive than galactomannan antigen, although we believe to be very promising in the diagnosis of aspergillosis invasive pulmonary after improving its optimization.
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Ciências biomédicas Biologia molecular Fungos Análise e diagnóstico
Contexto Educativo
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Editora
Instituto de Higiene e Medicina Tropical