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, irrigationaspiration 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.

The occurrence of Salmonella Enteritidis (SE) phage types (PTs) in samples collected from healthy and diseased chickens, in outbreaks of human gastroenteritis related to the consumption of egg products, in samples of poultry meat, in pipped embryos of broiler chickens, in meat meal, in poultry-rearing environments, and in many foods (cheese, mayonnaise, cake, and bacon) is described for strains isolated from 1995 to 1997 in Brazil. SE strains were isolated, and the most common PT was found to be PT 4, followed by PTs 7, 21, 35, 6, 4a, 8, 30, 6a, 5a, 1, and 1b. Fourteen strains were classified as react-but-do-not-conform strains, and one strain was not typeable. The results of this study demonstrate that PT 4 has a wider distribution among the sources studied than do any other SE phage types and is the most important phage type in human salmonellosis.

It was concluded that patients with megaesophagus present some bacteria in the esophageal lumen that are able to reduce nitrates intro nitrites, an important step in the formation of N-nitroso compounds.

Small bowel bacterial growth was studied in patients with strongyloidiasis, and the results were compared to controls. We concluded that in strongyloidiasis there is small bowel bacterial overgrowth, and so it should be considered in the pathogenesis of some of the gastrointestinal manifestations and complications of strongyloidiasis.

INTRODUCTIONIndigenous microbiota is highly competitive with other microorganisms in multiplication [1] . Experimental studies have shown the importance of this microbiota (anaerobes only) to avoid colonization of transitory microbiota [2] , which is more effective than the protection provided by immunological mechanisms [3] . However, these studies were limited to the analysis of only the anaerobic flora, some segments of the colon utilizing feces samples or luminal content. Additionally, it is difficult to identify and quantify anaerobic and/or yeast microorganisms involved in infectious processes.The social and practical benefit of investigating indigenous microbiota is to enable investigators to improve prophylactic/therapeutic methods when antimicrobials are used to determine biological markers and to establish a normal pattern utilized for the analysis of microbiological behavior in different diseases of the lower digestive tract.The aim of this study was to analyze prospectively the indigenous microbiota (qualitative and quantitatively) at different sites of the lower digestive tract in healthy volunteers with a standardized method of collecting intestinal mucous after bowel preparation for colonoscopy for routine utilization in screening patients. MATERIALS AND METHODS T h i s p r o s p e c t ive s t u d y wa s p e r f o r m e d w i t h t h e participation of the Microbiological Laboratory of the