Infecção por Giardia duodenalis e diversidade da microbiota intestinal em crianças de 0 a 6 anos de idade
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Data
2019-08-28
Autores
Arbex, Ana Paula Oliveira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Giardia duodenalis é um dos principais agentes etiológicos de diarreia infecciosa, sobretudo em crianças em idade pré-escolar que vivem em comunidades de baixa renda. Estudos da diversidade genética de G. duodenalis ampliaram o conhecimento da epidemiologia nas infecções humanas, entretanto um dos temas mais interessantes e menos conhecidos é a possível interação de Giardia com o microbioma do hospedeiro e com patógenos concomitantes. No presente estudo, avaliou-se a composição e a diversidade da comunidade bacteriana de crianças saudáveis e crianças com diarreia, parasitadas por Giardia e outros protozoários intestinais. Os isolados de Giardia obtidos nessa população foram caracterizados geneticamente. Amostras de fezes foram obtidas de 181 crianças de 0 a 6 anos de idade, das quais 156 crianças hígidas atendidas em centros de educação infantil e 25 crianças com diarreia atendidas no PS Infantil Municipal. Cada amostra de fezes foi processada para o exame microscópico e submetida à extração de DNA a ser empregado em duas etapas distintas: (1) amplificação e sequenciamento Sanger para a caracterização genética de Giardia e o diagnóstico de Blastocystis sp, Dientamoeba fragilis, Enterocytozoon bieneusi e Cryptosporidium spp. e (2) amplificação do gene 16s RNA ribossomal e sequenciamento de nova geração (plataforma Illumina MiSeq) para a caracterização da microbiota intestinal. Giardia (36,5%) e Blastocystis (41,7%) foram os parasitas mais prevalentes. A caracterização genética de 61 isolados de Giardia revelou infecções por assemblages A (64%), B (33%) e infecções mistas A+B (3%). As análises metagenômicas revelaram similaridade da diversidade e riqueza do microbioma bacteriano entre os grupos de crianças assintomáticas e parasitadas por Giardia e/ou outros protozoários e o grupo de crianças não parasitadas em comparação com o grupo de crianças com Giardia e diarreia. Redução e aumento marcantes da abundância relativa, respectivamente, nos filos Bacteroidetes e Proteobacteria foram observados no grupo de crianças com diarreia. Aumento do filo Verrucomicrobia com predomínio do gênero Akkermansia foi observado nas infecções sintomáticas e assintomáticas por este protozoário, particularmente no grupo com diarreia. Além disso, Bifidobacterium foi mais abundante nas crianças com giardíase sintomática do que nos casos assintomáticos. A despeito dessas variações, geralmente a colonização por Giardia mostrou-se associadas associada a uma microbiota saudável. A existência de associações entre parasitas intestinais e diversidade de microbiota é um fato, porém requer mais estudos.
Giardia duodenalis is one of the major etiological agents of infectious diarrhea, especially in preschool children living in low-income settings. Studies focused on genetic diversity of G. duodenalis have provided insights for a better understanding of epidemiology in human infections. However, one of the most interesting and least known issues is the possible interplay between Giardia and the host microbiome and concomitant pathogens. In this work, we evaluated the diversity and composition of bacterial community of healthy children and children presenting with diarrhea infected by Giardia and/or other intestinal protozoa. In addition, Giardia isolates infecting this population were genotyping. A total of 181 stool samples from children aged 0 to 6 years old (156 from daycare children and 25 from diarrheic children attending in an emergence pediatric center) were tested by microscopic examination and submitted to DNA extraction for the following steps: (1) conventional PCR/sequencing for Giardia genotyping and the diagnosis of Blastocystis sp, Dientamoeba fragilis, Enterocytozoon bieneusi and Cryptosporidium spp and (2) next-generation sequencing (Illumina MiSeq) based analysis of intestinal microbiota. Giardia (36.5%) and Blastocystis (41.7%) were the most prevalent parasites. Analysis of Giardia sequences retrieved from 61 isolates revealed infections by assemblages A (31%), B (69%) and mixed infections A+B (3%). Metagenomic analyzes revealed similarity of bacterial microbiome diversity and richness between asymptomatic children infecting by Giardia and/or other protozoa and the group of non-parasitized children compared to the group of children with Giardia and diarrhea. Metagenomic analysis revealed significant reduction and increase in relative abundance, respectively, in the Bacteroidetes and Proteobacteria phyla were observed in the group of Giardia-positive children with diarrhea. In addition, an increase in the phylum Verrucomicrobia with a predominance of the genus Akkermansia was observed in both symptomatic and asymptomatic children. In addition, Bifidobacterium was more abundant in children with symptomatic giardiasis than in asymptomatic cases. Despite these variations, Giardia colonization is usually associated with a healthy gut microbiota. The existence of associations between intestinal parasites and microbiota diversity is a fact but it needs further studies.
Giardia duodenalis is one of the major etiological agents of infectious diarrhea, especially in preschool children living in low-income settings. Studies focused on genetic diversity of G. duodenalis have provided insights for a better understanding of epidemiology in human infections. However, one of the most interesting and least known issues is the possible interplay between Giardia and the host microbiome and concomitant pathogens. In this work, we evaluated the diversity and composition of bacterial community of healthy children and children presenting with diarrhea infected by Giardia and/or other intestinal protozoa. In addition, Giardia isolates infecting this population were genotyping. A total of 181 stool samples from children aged 0 to 6 years old (156 from daycare children and 25 from diarrheic children attending in an emergence pediatric center) were tested by microscopic examination and submitted to DNA extraction for the following steps: (1) conventional PCR/sequencing for Giardia genotyping and the diagnosis of Blastocystis sp, Dientamoeba fragilis, Enterocytozoon bieneusi and Cryptosporidium spp and (2) next-generation sequencing (Illumina MiSeq) based analysis of intestinal microbiota. Giardia (36.5%) and Blastocystis (41.7%) were the most prevalent parasites. Analysis of Giardia sequences retrieved from 61 isolates revealed infections by assemblages A (31%), B (69%) and mixed infections A+B (3%). Metagenomic analyzes revealed similarity of bacterial microbiome diversity and richness between asymptomatic children infecting by Giardia and/or other protozoa and the group of non-parasitized children compared to the group of children with Giardia and diarrhea. Metagenomic analysis revealed significant reduction and increase in relative abundance, respectively, in the Bacteroidetes and Proteobacteria phyla were observed in the group of Giardia-positive children with diarrhea. In addition, an increase in the phylum Verrucomicrobia with a predominance of the genus Akkermansia was observed in both symptomatic and asymptomatic children. In addition, Bifidobacterium was more abundant in children with symptomatic giardiasis than in asymptomatic cases. Despite these variations, Giardia colonization is usually associated with a healthy gut microbiota. The existence of associations between intestinal parasites and microbiota diversity is a fact but it needs further studies.
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Palavras-chave
parasitas intestinais, crianças, Giardia duodenalis, diversidade genética, Sequenciamento de Nova Geração (GS), microbiota, intestinal parasite, children, genetic diversity, Next Generation Sequencing (NGS)