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Identificação molecular de bactérias do género Leptospira em coleções de água doce no distrito de Leiria
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A Leptospirose é uma zoonose de distribuição mundial, causada por espiroquetas patogénicas do género Leptospira, cujos reservatórios principais são os roedores, mas também outros mamíferos (suínos e bovinos), que podem excretar leptospiras pela urina durante meses ou anos. Estas bactérias podem sobreviver na água durante muito tempo, tornando-se esta um meio de transmissão de grande importância, destas bactérias. A população humana em contacto com água contaminada fica assim exposta a um elevado risco de infeção.
O objetivo desta investigação foi detetar/identificar molecularmente bactérias do género Leptospira presentes em coleções de água doce no Distrito de Leiria (Portugal), e avaliar o risco de Leptospirose, face ao contacto da população com estas águas.
Analisaram-se 100 amostras de água, obtidas em 15 locais no referido distrito (rios, fontes, fontanários, lagoas). Utilizaram-se três protocolos de PCR para deteção de DNA leptospírico: i) uma nested-PCR com primers universais designados (A e B), obtidos do gene rrs (16S) para espiroquetas do género Leptospira; ii) uma segunda PCR (nas amostras positivas na primeira abordagem), usando primers (G1 e G2), desenhados no gene secY, presente em algumas espécies patogénicas de Leptospira; e iii) uma outra nested-PCR, com primers obtidos do gene lipL32 codificante da proteína de superfície com o mesmo nome, comum a todas as leptospiras patogénicas. Foram sequenciados alguns dos produtos amplificados, e os resultados foram analisados por BLAST quanto à similaridade com sequências depositadas no GenBank para as espécies de Leptospira.
Foi detetado DNA de Leptospira spp., em 41 amostras, das quais 28 (68,3%) corresponderam a leptospiras patogénicas, tendo a maioria revelado uma elevada similaridade (98 - 99%) com a espécie Leptospira interrogans.
Os resultados obtidos mostraram a presença inequívoca de leptospiras patogénicas nas coleções de água doce na região de Leiria, establecendo um alerta para as Autoridades de Saúde locais, no sentido da intervenção na melhoria da qualidade da água de modo a prevenir-se o risco de Leptospirose.
Leptospirosis is a zoonosis of worldwide distribution caused by pathogenic spirochetes of the genus Leptospira, whose main reservoir are rodents, but also other mammals (swine and bovines), which can shed leptospires through urine for months or years. These bacteria can survive in water for a long time, being therefore an important vehicle of Leptospira transmission to humans. So, the human population in contact with contaminated water is exposed to a high risk of infection. The purpose of this research is to identify the molecular level bacteria of Leptospira genus, present in freshwater collections in the Leiria's district (Portugal), and to evaluate the risk of leptospirosis, due to the contact of population with such waters. A total of 100 samples of freshwater collected from 15 locations previously selected, in that district (rivers, fountains, drinking fountains, ponds) was analized. Three PCR protocols for Leptospira DNA detection were used: i) a nested-PCR with universal primers (A and B), obtained from rrs (16S) gene for Leptospira genus; ii) a second PCR using primers (G1 and G2), drawn on secY gene present in some pathogenic Leptospira species; and iii) another nested-PCR targeting lipL32 gene, that encoding the surface protein with the same name, common to all pathogenic leptospires. Some of amplified products were sequenced and the results analyzed by BLAST, regarding to the similarity with sequences deposited in GenBank to Leptospira species. Leptospira spp., DNA was detected in 41 samples of which 28 (68.3%) matching to pathogenic leptospires, and the majority revealed a high similarity (98-99%) with Leptospira interrogans species. The obtained results showed an unequivocal presence of pathogenic leptospires in freshwater collections at the Leiria region, establishing an alert to the local Health Authorities, towards intervention in the improvement of water quality in order to prevent the risk of Leptospirosis.
Leptospirosis is a zoonosis of worldwide distribution caused by pathogenic spirochetes of the genus Leptospira, whose main reservoir are rodents, but also other mammals (swine and bovines), which can shed leptospires through urine for months or years. These bacteria can survive in water for a long time, being therefore an important vehicle of Leptospira transmission to humans. So, the human population in contact with contaminated water is exposed to a high risk of infection. The purpose of this research is to identify the molecular level bacteria of Leptospira genus, present in freshwater collections in the Leiria's district (Portugal), and to evaluate the risk of leptospirosis, due to the contact of population with such waters. A total of 100 samples of freshwater collected from 15 locations previously selected, in that district (rivers, fountains, drinking fountains, ponds) was analized. Three PCR protocols for Leptospira DNA detection were used: i) a nested-PCR with universal primers (A and B), obtained from rrs (16S) gene for Leptospira genus; ii) a second PCR using primers (G1 and G2), drawn on secY gene present in some pathogenic Leptospira species; and iii) another nested-PCR targeting lipL32 gene, that encoding the surface protein with the same name, common to all pathogenic leptospires. Some of amplified products were sequenced and the results analyzed by BLAST, regarding to the similarity with sequences deposited in GenBank to Leptospira species. Leptospira spp., DNA was detected in 41 samples of which 28 (68.3%) matching to pathogenic leptospires, and the majority revealed a high similarity (98-99%) with Leptospira interrogans species. The obtained results showed an unequivocal presence of pathogenic leptospires in freshwater collections at the Leiria region, establishing an alert to the local Health Authorities, towards intervention in the improvement of water quality in order to prevent the risk of Leptospirosis.
Descrição
Palavras-chave
Microbiologia médica Bacteriologia Leptospira Roedores Análise multivariada
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical