Elisabeth Norin

Differences in Fecal Microbiota in Different European Study Populations in Relation to Age, Gender, and Country: a Cross-Sectional Study

ABSTRACT A cross-sectional study on intestinal microbiota composition was performed on 230 healthy subjects at four European locations in France, Germany, Italy, and Sweden. The study participants were assigned to two age groups: 20 to 50 years (mean age, 35 years; n = 85) and >60 years (mean age, 75 years; n = 145). A set of 14 group- and species-specific 16S rRNA-targeted oligonucleotide probes was applied to the analysis of fecal samples by fluorescence in situ hybridization coupled with flow cytometry. Marked country-age interactions were observed for the German and Italian study groups. These interactions were inverse for the predominant bacterial groups Eubacterium rectale-Clostridium coccoides and Bacteroides-Prevotella. Differences between European populations were observed for the Bifidobacterium group only. Proportions of bifidobacteria were two- to threefold higher in the Italian study population than in any other study group, and this effect was independent of age. Higher proportions of enterobacteria were found in all elderly volunteers independent of the location. Gender effects were observed for the Bacteroides-Prevotella group, with higher levels in males than in females. In summary, age-related differences in the microbiota makeup were detected but differed between the study populations from the four countries, each showing a characteristic colonization pattern.

Intestinal microbiota of 6-week-old infants across Europe: geographic influence beyond delivery mode, breast-feeding, and antibiotics

Objectives: There are many differences in diet and lifestyle across Europe that may influence the development of the infant gut microbiota. This work aimed to assess the impact of geographic area, mode of delivery, feeding method, and antibiotic treatment on the fecal microbiota of infants from 5 European countries with different lifestyle characteristics: Sweden, Scotland, Germany, Italy, and Spain. Patients and Methods: Fecal samples from 606 infants (age 6 weeks) recruited within the European project INFABIO were analyzed by fluorescent in situ hybridization combined with flow cytometry using a panel of 10 rRNA targeted group- and species-specific oligonucleotide probes. Information on factors potentially affecting gut microbiota composition was collected with questionnaires and associations were evaluated with multivariate analyses. Results: The Bifidobacterium genus was predominant (40% average proportion of total detectable bacteria), followed by Bacteroides (11.4%) and enterobacteria (7.5%). Northern European countries were associated with higher proportions of bifidobacteria in infant feces, whereas a more diverse microbiota with more bacteroides characterized southern countries. Bifidobacteria dominated the microbiota of breast-fed infants, whereas formula-fed babies had significantly higher proportions of Bacteroides and members of the Clostridium coccoides and Lactobacillus groups. Newborns delivered by cesarean section or from mothers treated with antibiotics perinatally had lower proportions of Bacteroides and members of the Atopobium cluster. Conclusions: Delivery mode and feeding method influenced the fecal microbiota of European infants at 6 weeks, as expected, but the effect of country of birth was more pronounced, with dominant bifidobacteria in northern countries and greater early diversification in southern European countries.

Modulation of Mucosal Immune Response, Tolerance, and Proliferation in Mice Colonized by the Mucin-Degrader Akkermansia muciniphila

Epithelial cells of the mammalian intestine are covered with a mucus layer that prevents direct contact with intestinal microbes but also constitutes a substrate for mucus-degrading bacteria. To study the effect of mucus degradation on the host response, germ-free mice were colonized with Akkermansia muciniphila. This anaerobic bacterium belonging to the Verrucomicrobia is specialized in the degradation of mucin, the glycoprotein present in mucus, and found in high numbers in the intestinal tract of human and other mammalian species. Efficient colonization of A. muciniphila was observed with highest numbers in the cecum, where most mucin is produced. In contrast, following colonization by Lactobacillus plantarum, a facultative anaerobe belonging to the Firmicutes that ferments carbohydrates, similar cell-numbers were found at all intestinal sites. Whereas A. muciniphila was located closely associated with the intestinal cells, L. plantarum was exclusively found in the lumen. The global transcriptional host response was determined in intestinal biopsies and revealed a consistent, site-specific, and unique modulation of about 750 genes in mice colonized by A. muciniphila and over 1500 genes after colonization by L. plantarum. Pathway reconstructions showed that colonization by A. muciniphila altered mucosal gene expression profiles toward increased expression of genes involved in immune responses and cell fate determination, while colonization by L. plantarum led to up-regulation of lipid metabolism. These indicate that the colonizers induce host responses that are specific per intestinal location. In conclusion, we propose that A. muciniphila modulates pathways involved in establishing homeostasis for basal metabolism and immune tolerance toward commensal microbiota.

Determinants of the human infant intestinal microbiota after the introduction of first complementary foods in infant samples from five European centres

Although it is well established that early infant feeding has a major influence on the establishment of the gut microbiota, very little is understood about how the introduction of first solid food influences the colonization process. This study aimed to determine the impact of weaning on the faecal microbiota composition of infants from five European countries (Sweden, Scotland, Germany, Italy and Spain) which have different lifestyle characteristics and infant feeding practices. Faecal samples were collected from 605 infants approximately 4 weeks after the introduction of first solid foods and the results were compared with the same infants before weaning (6 weeks of age) to investigate the association with determining factors such as geographical origin, mode of delivery, previous feeding method and age of weaning. Samples were analysed by fluorescence in situ hybridization and flow cytometry using a panel of 10 rRNA targeted group- and species-specific oligonucleotide probes. The genus Bifidobacterium (36.5 % average proportion of total detectable bacteria), Clostridium coccoides group (14 %) and Bacteroides (13.6 %) were predominant after weaning. Similar to pre-weaning, northern European countries were associated with a higher proportion of bifidobacteria in the infant gut microbiota while higher levels of Bacteroides and lactobacilli characterized southern European countries. As before weaning, the initial feeding method influenced the Clostridium leptum group and Clostridium difficile+Clostridium perfringens species, and bifidobacteria still dominated the faeces of initially breast-fed infants. Formula-fed babies presented significantly higher proportions of Bacteroides and the C. coccoides group. The mode of birth influenced changes in the proportions of bacteroides and atopobium. Although there were significant differences in the mean weaning age between countries, this was not related to the populations of bifidobacteria or bacteroides. Thus, although the faecal microbiota of infants after first complementary foods was different to that before weaning commenced, many of the initial influences on microbiota composition were still evident.

Gut Microflora Associated Characteristics in Children with Celiac Disease

OBJECTIVES:The aim of the study was to investigate the metabolic function of intestinal microflora in children with celiac disease (CD) in order to find out if there is a deviant gut flora in CD patients compared to healthy controls.METHODS:The study group comprised children with CD, consecutively diagnosed according to current criteria given by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition. Thirty-six children were studied at presentation, i.e., on a normal gluten-containing diet, with clinical symptoms and signs indicative of CD, positive celiac serology markers, and a small bowel biopsy showing severe enteropathy. Forty-seven patients were studied when they had been on a gluten-free diet (GFD) for at least 3 months. For comparison, a group of 42 healthy controls (HC) were studied. The functional status of the intestinal microflora was evaluated by gas–liquid chromatography of short chain fatty acids (SCFAs) in fecal samples.RESULTS:There was a significant difference between untreated CD children and HC as well as between treated CD children and HC regarding acetic, i-butyric, i-valeric acid, and total SCFAs. The propionic and n-valeric acids differed significantly between CD children on GFD and HC. Moreover, there was a strong correlation between i-butyric and i-valeric acids in all study groups.CONCLUSIONS:This is the first study of the SCFA pattern in fecal samples from children with CD. The results indicate that there is a difference in the metabolic activity of intestinal microbial flora in children with CD compared to that in HC. The finding of a different pattern of some SCFAs in celiacs both at presentation and during treatment with GFD indicates that it is a genuine phenomenon of CD not affected by either the diet, the inflammation, or the autoimmune status of the patient.

An anthroposophic lifestyle and intestinal microflora in infancy.

The intestinal flora is considered to have an impact on the development of the immune system. In the anthroposophic lifestyle, a diet comprising vegetables spontaneously fermented by lactobacilli, and a restrictive use of antibiotics, anti‐pyretics and vaccinations, is typical. The aim of this study was to assess the gut flora in infants in relation to certain lifestyle characteristics associated with anthroposophy. Sixty‐nine children < 2 years of age with an anthroposophic lifestyle, and 59 infants of a similar age with a traditional lifestyle, were clinically examined and questionnaire replies assessed. Fecal samples were analyzed by bacterial enumeration, bacterial typing through biochemical fingerprinting and by measuring microflora‐associated characteristics (MACs). The numbers of colony‐forming units (CFU)/g of feces were significantly higher for enterococci and lactic acid bacteria in children who had never been exposed to antibiotics (5.5 × 107 vs. 2.1 × 107; p < 0.001 and 10 × 107 vs. 4.1 × 107; p < 0.01, respectively). Furthermore, the number of enterococci was significantly higher in breastfed and vegetarian infants (p < 0.01). The diversity (Simpsons diversity index) of lactobacilli, as determined by biochemical fingerprinting, was higher in infants born at home than in those born in hospital (p < 0.01). Several MACs were related to specific lifestyle features, and infants with an anthroposophic lifestyle had a higher proportion of acetic acid and a lower proportion of propionic acid in their stool as compared to the control children. In conclusion, lifestyle factors related to the anthroposophic way of life influenced the composition of the gut flora in the infants. These differences may contribute to the lower prevalence of atopic disease previously observed in children in anthroposophic families.

Increased Enterocyte Production in Gnotobiotic Rats Mono-Associated with Lactobacillus rhamnosus GG

ABSTRACT There is increasing scientific and commercial interest in using beneficial microorganisms (i.e., probiotics) to enhance intestinal health. Of the numerous microbial strains examined, Lactobacillus rhamnosus GG has been most extensively studied. Daily intake of L. rhamnosus GG shortens the course of rotavirus infection by mechanisms that have not been fully elucidated. Comparative studies with germfree and conventional rats have shown that the microbial status of an animal influences the intestinal cell kinetics and morphology. The present study was undertaken to study whether establishment of L. rhamnosus GG as a mono-associate in germfree rats influences intestinal cell kinetics and morphology. L. rhamnosus GG was easily established in germfree rats. After 3 days of mono-association, the rate of mitoses in the upper part of the small intestine (jejunum 1) increased as much as 14 and 22% compared to the rates in germfree and conventional counterparts, respectively. The most striking alteration in morphology was an increase in the number of cells in the villi. We hypothesis that the compartmentalized effects of L. rhamnosus GG may represent a reparative event for the mucosa.

Faecal Short-Chain Fatty Acids in Patients with Antibiotic-Associated Diarrhoea, before and after Faecal Enema Treatment

BACKGROUND Antibiotic-associated diarrhoea (AAD) may range from mild disturbances to severe pseudomembranous colitis. Many antibiotics affect several intestinal microflora-associated characteristics, such as short-chain fatty acid (SCFA) pattern. In the present study we investigated SCFAs in 31 patients on admittance to the hospital for severe AAD. Nine patients were followed up more extensively after they had received an enema containing faecal microflora from a healthy person on a Western diet. METHODS Faecal SCFAs were determined by gas chromatography. The enema was characterized before use. RESULTS AAD patients showed significant disturbances in faecal SCFA pattern. Clinically, most enema-treated patients recovered within days and had no relapses within 18 months. CONCLUSIONS Intestinal microflora showed great disturbances, and the amounts of SCFAs were reduced, although the diarrhoea was not related to total amount SCFAs. Administration of a faecal enema resulted in the clinical recovery of most patients with severe diarrhoea within 4 days.

The Effect of Faecal Enema on Five Microflora-Associated Characteristics in Patients with Antibiotic-Associated Diarrhoea

BACKGROUND Patients with antibiotic-associated diarrhoea (AAD) show significant disturbances in short-chain fatty acid pattern. In the present study five more microflora-associated characteristics (MACs) were investigated before and after administration of an enema containing faecal microflora from a healthy person on a Western diet. METHODS The functions of the microflora were determined with gas chromatography, electrophoresis, and spectrophotometry. RESULTS The conversion of cholesterol to coprostanol and the concentration of urobilinogen and trypsin were significantly reduced in comparison with healthy persons. The pattern of mucin was altered, but beta-aspartylglycine remained the same as in healthy persons. Enema treatment influenced these functions to different extents. CONCLUSION Most MACs were significantly disturbed in patients with AAD. Administration of a human faecal enema modified these changes and relieved diarrhoea, usually within 4 days.

Fecal transplant against relapsing Clostridium difficile-associated diarrhea in 32 patients

Abstract Clostridium difficile-associated disease (CDAD) with frequent watery stools, sometimes with painful bowel movements, fever and sickness, is probably the major known cause of antibiotic-associated diarrhea and colitis, most probably depending on a disruption of the normal intestinal balance in the microbiome. In this study, we have inoculated a mixture of fecal microbes – as an enema – originating from a healthy Scandinavian middle-aged donor, regularly re-cultivated under strict anaerobic conditions for more than 10 years, to 32 patients. Twenty-two patients (69%) were durably cured. In those patients receiving the transplant by colonoscopy, four out of five were cured. To the best of our knowledge, this is the first time a fecal culture of microbes has retained the possibility for years to cure a substantial number of patients with CDAD.