Digestive tract microbiota in healthy volunteers

PURPOSE: The aim of this study was to standardize the methods of sample collection of mucus from the digestive tract and to determine the microbiota in healthy volunteers from Brazil, collecting samples from the mouth, esophagus, stomach, duodenum, jejunum, ileum, colon, and rectum. METHODS: Microbiota of selected healthy volunteers from the oral cavity (n=10), the esophagus (n=10), the upper digestive tract (n=20), and the lower digestive tract (n=24) were evaluated through distinct collection methods. Collection methods took into account the different sites, using basic scraping and swabbing techniques, stimulated saliva from the oral cavity, irrigation-aspiration with sterile catheters especially designed for the esophagus, a probe especially designed for upper digestive tract, and a special catheter for the lower digestive tract. RESULTS: (i) Mixed microbiota were identified in the oral cavity, predominantly Gram-positive aerobic and anaerobic cocci; (ii) transitional flora mainly in the esophagus; (iii) Veillonella sp, Lactobacillus sp, and Clostridium sp in the stomach and duodenum; (iv) in the jejunum and upper ileum, we observed Bacteroides sp, Proteus sp, and Staphylococcus sp, in addition to Veillonella sp; (v) in the colon, the presence of "nonpathogenic" anaerobic bacteria Veillonella sp (average 10(5) UFC) indicates the existence of a low oxidation-reduction potential environment, which suggests the possibility of adoption of these bacteria as biological markers of total digestive tract health. CONCLUSIONS: The collection methods were efficient in obtaining adequate samples from each segment of the total digestive tract to reveal the normal microbiota. These procedures are safe and easily reproducible for microbiological studies.

OBJETIVO: Padronizar os métodos de coleta do muco do trato digestivo e determinar a microbiota, em voluntários saudáveis no Brasil, coletando amostras da boca, esôfago, estômago, duodeno, jejunos e íleo, cólons e reto. MÉTODOS: A microbiota de voluntários saudáveis foi avaliada através de diferentes métodos de coleta: cavidade oral (n=10 voluntários), do esôfago (n=10), do trato digestivo alto (n=20) e do trato digestivo baixo (n=24). Métodos de coleta foram adotados em cada sítio restrito, usando derramar saliva, técnica de esfregar a mucosa e saliva estimulada da cavidade oral, irrigação-aspiração, cateteres específicos designados para o esôfago, sonda especial para o trato digestivo alto e cateteres especiais para o trato digestivo baixo. RESULTADOS: Identificados: (i) na cavidade oral, microbiota mista, predominando cocos aeróbios e anaeróbios Gram positivos; (ii) no esôfago, flora transitória; (iii) no estômago e duodeno, Veillonella sp, Lactobacillus sp and Clostridium sp; (iv) no jejuno e íleo proximal, Bacteróides sp, Proteus sp and Staphilococcus sp, além da Veillonella sp ; (v) no colon, foi revelada a presença "não patogênica" da bactéria anaeróbica Veillonella sp numa concentração média de 10(5) unidades formadoras de colônia, indicando um meio de baixo potencial de oxido-redução e a possibilidade de se conceituar esta bactéria como um marcador biológico do trato digestivo total em sadios. CONCLUSÃO: Estes métodos de coleta foram considerados eficientes para obtenção adequada de amostra em cada segmento do trato digestivo total para caracterizar a microbiota normal. Estes procedimentos são seguros e facilmente reprodutível para estudo microbiológico.

Molecular epidemiology of Lyme disease spirochetes based on a probe complementary to ribosomal RNA

Lyme disease is caused by the spirochete, Borrelia burgdorferi, a bacteria which infects many vertebrates including humans. Borrelia have been isolated from many parts of the world, and there is interest to identify commun genetic markers to improve molecular methods of diagnosis, and to aid in understanding varied manifestations of the disease. A total of 48 Borrelia burgdorferi strains, including: 38 isolated from ticks (Ixodes dammini, I. persulcatus, I. ricinus and I. pacificus), 3 from animals (dog, bird and hamster), and 7 from human clinical cases (skin, CSF, plasma and blood) from different geographic areas, were studied by DNA/DNA hybridization and rRNA gene restriction patterns by using a biotinylated pKK3535 probe (Altewegg M., Mayer L.W., 1989). The migration patterns of rRNA generestriction fragments after clevage by Hind III separate these strains into 5 ribotypes of Borrelia burgdorferi: Type I (38 American, 2 European strains); Type II (13 American strains); Type III (3 Asian and 1 European strains); Type IV (1 European and 2 Asian strains) and Type V (1 Asian strain). The use of ribotyping has provided and additional tool to investigate the diferences or commun patterns which cause various Lyme disease syndromes.