| 1. |
- Hugerth, Luisa W., et al.
(author)
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No distinct microbiome signature of irritable bowel syndrome found in a Swedish random population
- 2020
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In: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 69:6, s. 1076-1084
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Journal article (peer-reviewed)abstract
- Objective The ethiopathogenesis of irritable bowel syndrome (IBS) is unknown. While a link to the gut microbiome is postulated, the heterogeneity of the healthy gut makes it difficult to draw definitive conclusions. We aimed to describe the faecal and mucosa-associated microbiome (MAM) and health correlates on a community cohort of healthy and IBS individuals with no colonoscopic findings.Design The PopCol study recruited a random sample of 3556 adults; 745 underwent colonoscopy. IBS was defined by Rome IV criteria and organic disease excluded. 16S rRNA gene sequencing was conducted on sigmoid biopsy samples from 376 representative individuals (63 IBS cases) and faecal samples from 185 individuals (32 IBS cases).Results While sigmoid MAM was dominated by Lachnospiraceae, faeces presented a higher relative abundance of Ruminococcaceae. Microbial richness in MAM was linearly correlated to that in faeces from the same individual (R-2=0.255, p<3E-11) as was diversity (R-2=0.06, p=0.0022). MAM diversity decreased with increasing body mass index (BMI; Pearson's r=-0.1, p=0.08) and poorer self-rated health (r=-0.15, p=0.007), but no other health correlates. Faecal microbiome diversity was correlated to stool consistency (r=-0.16, p=0.043). Several taxonomic groups were correlated to age, BMI, depression and self-reported health, including Coprococcus catus associated with lower levels of depression (r=-0.003, p=0.00017). The degree of heterogeneity observed between IBS patients is higher than that observed between healthy individuals.Conclusions No distinct microbial signature was observed in IBS. Individuals presenting with low self-rated health or high BMI have lower gut microbiome richness.
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| 2. |
- Thorell, Kaisa, et al.
(author)
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Isolates from Colonic Spirochetosis in Humans Show High Genomic Divergence and Potential Pathogenic Features but Are Not Detected Using Standard Primers for the Human Microbiota
- 2019
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In: Journal of Bacteriology. - 0021-9193 .- 1098-5530. ; 201:21
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Journal article (peer-reviewed)abstract
- Colonic spirochetosis, diagnosed based on the striking appearance in histological sections, still has an obscure clinical relevance, and only a few bacterial isolates from this condition have been characterized to date. In a randomized, population-based study in Stockholm, Sweden, 745 healthy individuals underwent colonoscopy with biopsy sampling. Of these individuals, 17 (2.3%) had colonic spirochetosis, which was associated with eosinophilic infiltration and a 3-fold-increased risk for irritable bowel syndrome (IBS). We aimed to culture the bacteria and perform whole-genome sequencing of the isolates from this unique representative population sample. From 14 out of 17 individuals with spirochetosis we successfully isolated, cultured, and performed whole-genome sequencing of in total 17 isolates, including the Brachyspira aalborgi type strain, 513A. Also, 16S analysis of the mucosaassociated microbiota was performed in the cases and nonspirochetosis controls. We found one isolate to be of the species Brachyspira pilosicoli; all remaining isolates were of the species Brachyspira aalborgi. Besides displaying extensive genetic heterogeneity, the isolates harbored several mucin-degrading enzymes and other virulenceassociated genes that could confer a pathogenic potential in the human colon. We also showed that 16S amplicon sequencing using standard primers for human microbiota studies failed to detect Brachyspira due to primer incompatibility. IMPORTANCE This is the first report of whole-genome analysis of clinical isolates from individuals with colonic spirochetosis. This characterization provides new opportunities in understanding the physiology and potentials of these bacteria that densely colonize the gut in the individuals infected. The observation that standard 16S amplicon primers fail to detect colonic spirochetosis may have major implications for studies searching for associations between members of the microbiota and clinical conditions such as irritable bowel syndrome (IBS) and should be taken into consideration in project design and interpretation of gastrointestinal tract microbiota in population-based and clinical settings.
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| 3. |
- Walker, Marjorie M., et al.
(author)
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Colonic spirochetosis is associated with colonic eosinophilia and irritable bowel syndrome in a general population in Sweden
- 2015
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In: Human Pathology. - : Elsevier BV. - 0046-8177 .- 1532-8392. ; 46:2, s. 277-283
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Journal article (peer-reviewed)abstract
- Irritable bowel syndrome (IBS) is a functional disorder defined by symptoms in the absence of overt pathology. Colonic spirochetosis (CS), defined by histologic observation of spirochetal strains of Brachyspira in colonic biopsies, is uncommon and considered of doubtful significance. We aimed to determine the prevalence of CS in the general population, identify subtle colon pathologies, and evaluate a link with symptoms of IBS. Colonoscopy was performed in 745 subjects (aged 19-70 years, mean age 51 years, 43% male) with biopsies (ileum and 4 colonic sites) from a random population sample, Stockholm, Sweden, who completed a validated questionnaire of gastrointestinal symptoms; IBS was identified by Rome III criteria. CS was identified by histology and immunohistochemistry. In a general population, 17 individuals (2.28%; 95% confidence interval, 1.2%-3.5%) were diagnosed as having CS by histology; 6 (35%) had IBS. CS was always present in the sigmoid colon, but only 14 rectal biopsies. Eosinophils were increased in colon biopsies in CS cases versus controls, in the transverse (p = .02), sigmoid colon (P = .001), and rectum (P = .0005) with subepithelial eosinophil clusters (P = .053). Lymphoid follicles (at any site) were present in 13 CS (P = .0003). There was a 3-fold increased risk of IBS in CS (odds ratio, 3.59; 95% confidence interval, 1.27-10.11; P = .015). Polyps and diverticular disease were similar in CS cases and controls. The prevalence of CS in a general population is 2% and associated with nonconstipating IBS. Colonic eosinophilia with lymphoid follicles may signify the presence of CS.
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| 4. |
- Agreus, Lars, et al.
(author)
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Towards a healthy stomach? : Helicobacter pylori prevalence has dramatically decreased over 23 years in adults in a Swedish community
- 2016
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In: United European Gastroenterology journal. - : Wiley. - 2050-6406 .- 2050-6414. ; 4:5, s. 686-696
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Journal article (peer-reviewed)abstract
- Background In Western countries the prevalence of Helicobacter pylori (H. pylori) infection may be declining but there is a lack of recent longitudinal population studies. We evaluated the changing epidemiology over a 23-year period in Sweden.Materials and methods In 1989, the validated Abdominal Symptom Questionnaire (ASQ) was mailed to a random sample of inhabitants (ages 22-80 years) in a Swedish community, and 1097 (87%) responded. H. pylori serology was analysed in a representative subsample (n=145). Twenty-three years later, the ASQ was mailed again using similar selection criteria, and 388 out of 1036 responders had an upper endoscopy with assessment of H. pylori and corpus atrophy status.Results The prevalence of positive H. pylori serology decreased from 37.9% (1989) to 15.8% (2012), corresponding to a decrease in odds of 75% per decade (odds ratio (OR): 0.25; 95% confidence interval (CI): 0.11-0.59, p=0.001) independent of age, gender, body mass index (BMI) and level of education, with a pattern consistent with a birth cohort effect. The prevalence increased with increasing age (p=0.001). The prevalence of H. pylori on histology in 2012 was 11.4% (95% CI 8.6-15.0). The prevalence of corpus atrophy on serology and/or histology in 2012 was 3.2% (95% CI 1.8-5.5); all cases were 57 years old.Conclusion The stomach is healthier in 2012 compared with 1989. H. pylori prevalence in adults has decreased over the last two decades to a level where clinical management might be affected.
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| 5. |
- Alexandersson, Bjarki T., et al.
(author)
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Diverticulosis is not associated with altered gut microbiota nor is it predictive of future diverticulitis : a population-based colonoscopy study
- 2023
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In: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 58:10, s. 1131-1138
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Journal article (peer-reviewed)abstract
- Background: The etiopathogenesis of diverticular disease is unknown.Objective: To compare the fecal and mucosa-associated microbiota between participants with and without diverticulosis and participants who later developed diverticulitis versus those that did not from a population-based study.Methods: The PopCol study, conducted in Stockholm, Sweden, invited a random sample of 3556 adults to participate, of which 745 underwent colonoscopy. Overall, 130 participants (17.5%) had diverticulosis. 16S rRNA gene sequencing was conducted on available sigmoid biopsy samples from 529 and fecal samples from 251 individuals. We identified individuals who subsequently developed acute diverticulitis up to 13 years after sample collection. In a case-control design matching for gender, age (+/−5 years), smoking and antibiotic exposure, we compared taxonomic composition, richness and diversity of the microbiota between participants with or without diverticulosis, and between participants who later developed acute diverticulitis versus those who did not.Results: No differences in microbiota richness or diversity were observed between participants with or without diverticulosis, nor for those who developed diverticulitis compared with those who did not. No bacterial taxa were significantly different between participants with diverticulosis compared with those without diverticulosis. Individuals who later developed acute diverticulitis (2.8%) had a higher abundance of genus Comamonas than those who did not (p = .027).Conclusions: In a population-based cohort study the only significant difference was that those who later develop diverticulitis had more abundance of genus Comamonas. The significance of Comamonas is unclear, suggesting a limited role for the gut microbiota in the etiopathogenesis of diverticular disease.
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| 6. |
- Carstens, Adam, 1975-, et al.
(author)
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Differential clustering of faecal and mucosa-associated microbiota in healthy individuals
- 2018
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In: Journal of Digestive Diseases. - : Wiley-Blackwell Publishing Asia. - 1751-2972 .- 1751-2980. ; 19:12, s. 745-752
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Journal article (peer-reviewed)abstract
- BACKGROUND: Faecal samples are often used to characterise gut microbiota, since they are easily collected. However, whether or not the faecal microbiota differ from the mucosa-associated microbiota remains largely unknown. This may be specifically relevant in conditions that are characterised by complex mucosal microbe-host interactions, such as Crohn's disease. We aimed to determine the degree of agreement between faecal and mucosal microbiota profiles in healthy individuals, using two commonly used collection procedures.MATERIAL AND METHODS: The gut microbiota composition of faecal samples (sent at ambient temperature before storage at -70°C) and of colonic biopsies (obtained at endoscopy and immediately stored at -70°C) was determined by sequencing the 16S rRNA gene. Thirty-one randomly selected healthy individuals from the population-based colonoscopy (Popcol) study were included.RESULTS: Faecal samples were characterised by a reduced degree of richness (p<0.0001) and diversity (p=0.016), and also differences in several phyla, including a lower relative abundance of Proteobacteria (p<0.0001) and Verrucomicrobia (p=0.008) than in biopsies. Only 3 of 30 individuals had a similar faecal and mucosal microbiota profile, based on weighted UniFrac analysis. A difference in Crohn's disease dysbiosis-associated bacteria was observed, including a lower relative abundance of Faecalibacterium (p=0.004) and a higher relative abundance of Ruminococcus (p=0.001) in faeces than in biopsies.CONCLUSIONS: Analysis of faecal samples that have been transported at ambient temperature does not adequately reflect the colonic mucosa-associated microbiota in healthy individuals. These findings have implications for the interpretation of the previous literature, and may be specifically relevant to studies on Crohn's disease.
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| 7. |
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| 8. |
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| 9. |
- Talley, Nicholas J., et al.
(author)
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Ileocolonic Histopathological and Microbial Alterations in the Irritable Bowel Syndrome : A Nested Community Case-Control Study
- 2021
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In: Clinical and Translational Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 2155-384X. ; 12:1
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Histopathological alterations in the ileum and colon in irritable bowel syndrome (IBS) are controversial, and normal values are poorly established. We hypothesized that changes in mucosal immune cells characterize IBS and key changes in immune composition are associated with the mucosa-associated microbiota (MaM).METHODS: A nested case-control study (48 IBS and 106 controls included) from 745 colonoscopy participants in a random population sample. Intraepithelial lymphocytes (IELs)/100 enterocytes and eosinophils/5 nonoverlapping high-power fields counted; mast cells identified by immunocytochemistry (CD117)/5 high-power fields. Paneth cells quantified per 5 crypts. 16S rRNA gene amplicon sequencing performed on available sigmoid MaM, n = 55 and fecal microbiota, n = 20. Microbiota profiles compared between samples with high and low IEL counts.RESULTS: IBS had increased IELs in the terminal ileum (relative risk ratio = 1.70, 95% confidence interval 1.08–2.76, P = 0.022 adjusted for age, sex, and smoking). Cecal IELs were increased in IBS—diarrhea (relative risk ratio = 2.03, 95% confidence interval 1.13–3.63, P = 0.017). No difference was observed in alpha diversity of MaM or fecal microbiota based on IEL count. There was no difference in beta diversity of the MaM according to IEL count in the terminal ileal (TI) (P = 0.079). High TI IEL counts associated with a significant expansion of the genus Blautia (P = 0.024) and unclassified Clostridiales (P = 0.036) in colon MaM.DISCUSSION: A modest but significant increase in IELs was observed in IBS vs. controls in a population-based setting. Subtle TI and cecal inflammation may play a pathogenic role in IBS but needs confirmation. Modest but discernible differences in the colonic MaM were seen according to TI IEL count but not IBS status.
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| 10. |
- Basmarke-Wehelie, Rahma, et al.
(author)
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The complement regulator CD46 is bactericidal to Helicobacter pylori and blocks urease activity
- 2011
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In: Gastroenterology. - Baltimore : Elsevier BV. - 0016-5085 .- 1528-0012. ; 141:3, s. 918-928
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Journal article (peer-reviewed)abstract
- BACKGROUND & AIMS: CD46 is a C3b/C4b binding complement regulator and a receptor for several human pathogens. We examined the interaction between CD46 and Helicobacter pylori (a bacterium that colonizes the human gastric mucosa and causes gastritis), peptic ulcers, and cancer.METHODS: Using gastric epithelial cells, we analyzed a set of H pylori strains and mutants for their ability to interact with CD46 and/or influence CD46 expression. Bacterial interaction with full-length CD46 and small CD46 peptides was evaluated by flow cytometry, fluorescence microscopy, enzyme-linked immunosorbent assay, and bacterial survival analyses.RESULTS: H pylori infection caused shedding of CD46 into the extracellular environment. A soluble form of CD46 bound to H pylori and inhibited growth, in a dose- and time-dependent manner, by interacting with urease and alkyl hydroperoxide reductase, which are essential bacterial pathogenicity-associated factors. Binding of CD46 or CD46-derived synthetic peptides blocked the urease activity and ability of bacteria to survive in acidic environments. Oral administration of one CD46 peptide eradicated H pylori from infected mice.CONCLUSIONS: CD46 is an antimicrobial agent that can eradicate H pylori. CD46 peptides might be developed to treat H pylori infection.
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