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Contribuição para o diagnóstico molecular das onicomicoses
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Onicomicose ou infecção fúngica das unhas das mãos ou dos pés pode ser provocada por fungos que invadem primariamente a lâmina ungueal saudável. Embora existam outros agentes, como por exemplo bactérias, que podem causar infecções ungueais, as infecções causadas por fungos são mais frequentes e são consideradas uma das principais onicopatias do homem. Os efeitos psicológicos e emocionais que resultam dos aspectos clínicos da onicomicose podem ser marcantes e ter um impacto significativo na qualidade de vida dos portadores. É uma doença com grande potencial crónico associada a uma séria dificuldade terapêutica, sendo estes os principais factores agravantes do seu prognóstico.
Conforme a extensão do comprometimento e a porção da unha envolvida na onicomicose, a infecção causada por fungos pode ser classificada em 5 tipos: onicomicose subungueal distal e lateral, onicomicose superficial leitosa, onicomicose subungueal proximal, onicomicose com distrofia total e onicomicose por candidose. São causadas por diferentes agentes etiológicos sendo que os mais comuns são os fungos dermatófitos (80 a 90%), seguidos pelas leveduras (5 a 17%) e fungos filamentosos não dermatófitos (2 a 12%).
Neste trabalho foram estudadas 54 amostras recolhidas de unhas de doentes com hipótese clínica de onicomicose, das quais 25,93% (14/54) pertenciam a indivíduos do sexo masculino e 74,07% (40/54) a indivíduos do sexo feminino. As técnicas convencionais de diagnóstico são morosas e muitas vezes de difícil caracterização a nível fenotipico, o que condiciona grandemente a implementação da terapêutica adequada.
O presente trabalho teve como principal objectivo a aquisição de conhecimentos que permitissem um correcto diagnóstico micológico das onicomicoses, através do isolamento e identificação das espécies de fungos causadoras de infecção. De uma forma global, consistiu inicialmente no isolamento e posteriormente na identificação dos agentes etiológicos de onicomicoses, utilizando para tal metodologias convencionais e moleculares. Foi realizado o diagnóstico laboratorial baseado no exame directo e na cultura de fragmentos de unhas provenientes de doentes com infecção. Paralelamente, foi extraído o DNA fúngico das mesmas amostras clínicas que, após amplificação da região ITS dos genes ribossómicos foi utilizado para confirmação e comparação dos resultados. Foi igualmente estudada a ocorrência de fungos não dermatófitos responsáveis por onicomicose. Os métodos moleculares de diagnóstico podem não só constituir uma alternativa mais rápida de diagnóstico micológico como também, por serem mais sensíveis, permitir a detecção de espécies que, por serem de crescimento fastidioso, não se desenvolvem em cultura.
Onychomycosis, or fungi infection on hands and feet’s nails, are caused by fungus that primary invade the healthy nail blade. Although there are other factors such as bacteria’s that can cause nail infections, the infections caused by fungi, are more frequent and can be considered one of the primary human onychopathies. The psychological and emotional effects caused by the clinical aspects of these infections, can have a major impact in the quality of life of those infected. The prognosis to these diseases is always aggravated by its very difficult therapy and great chronic potential. The infection can be classified in 5 different types, regarding the extension and percentage of fingernail affected: Distal and lateral subungueal onychomycosis; Endonyx onychomycosis or white superficial onychomycosis; Proximal subungueal onychomycosis; Total dystrophy onychomycosis or Candida Onychomycosis. The infection is caused by several different etiological agents. In most cases, 80% to 90%, the infection is caused by dermatophytes fungi, but it can also be caused by yeasts, in 5% to 17% of the cases, or even by filamentous non-dermatophyte fungi, in 2% to 12% of the cases. In this work were considered 54 samples, collected from unhealthy nails, with Onychomycosis clinical suspicion. Of these samples, 25.93% (14 out of 54) where obtained from masculine individuals and 70.07% (40 out of 54) where obtained from feminine individuals. Conventional diagnostic techniques are time consuming and of difficult phenotypic level characterization. Because of these, the correct therapeutic to be implemented is often difficult to achieve. The main objective of this work was to explore and compile existing knowledge, in order to obtain a correct mycological onychomycosis diagnosis, through the correct isolation and identification of the different species of fungi that can cause these infections. Holistically, onychomycosis etiological agents were isolated and identified, through the use of conventional and molecular methodologies. Laboratorial diagnosis was preformed based in direct sample analysis and fragment nail culture, using samples from the infected individuals. Fungi DNA were extracted from the same clinical samples. Ribosomal genes ITS region amplification was preformed to compare and confirm the results. The presence of non-dermatophyte fungi, responsible for Onychomycosis was also considered.
Onychomycosis, or fungi infection on hands and feet’s nails, are caused by fungus that primary invade the healthy nail blade. Although there are other factors such as bacteria’s that can cause nail infections, the infections caused by fungi, are more frequent and can be considered one of the primary human onychopathies. The psychological and emotional effects caused by the clinical aspects of these infections, can have a major impact in the quality of life of those infected. The prognosis to these diseases is always aggravated by its very difficult therapy and great chronic potential. The infection can be classified in 5 different types, regarding the extension and percentage of fingernail affected: Distal and lateral subungueal onychomycosis; Endonyx onychomycosis or white superficial onychomycosis; Proximal subungueal onychomycosis; Total dystrophy onychomycosis or Candida Onychomycosis. The infection is caused by several different etiological agents. In most cases, 80% to 90%, the infection is caused by dermatophytes fungi, but it can also be caused by yeasts, in 5% to 17% of the cases, or even by filamentous non-dermatophyte fungi, in 2% to 12% of the cases. In this work were considered 54 samples, collected from unhealthy nails, with Onychomycosis clinical suspicion. Of these samples, 25.93% (14 out of 54) where obtained from masculine individuals and 70.07% (40 out of 54) where obtained from feminine individuals. Conventional diagnostic techniques are time consuming and of difficult phenotypic level characterization. Because of these, the correct therapeutic to be implemented is often difficult to achieve. The main objective of this work was to explore and compile existing knowledge, in order to obtain a correct mycological onychomycosis diagnosis, through the correct isolation and identification of the different species of fungi that can cause these infections. Holistically, onychomycosis etiological agents were isolated and identified, through the use of conventional and molecular methodologies. Laboratorial diagnosis was preformed based in direct sample analysis and fragment nail culture, using samples from the infected individuals. Fungi DNA were extracted from the same clinical samples. Ribosomal genes ITS region amplification was preformed to compare and confirm the results. The presence of non-dermatophyte fungi, responsible for Onychomycosis was also considered.
Descrição
Palavras-chave
Microbiologia Médica Ciências Biomédicas Onicomicoses
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical