Medizinische Universität Graz - Research portal
Selected Publication:
Orgler, E.
Detecting the role of fungi, bacteria and archaea in intestinal biofilms of IBD and IBS patients.
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2020. pp. 95
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- Authors Med Uni Graz:
- Advisor:
- Moissl-Eichinger Christine
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- Abstract:
- INTRODUCTION Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS) have both rising incidences in Western societies, while etiologies remain unclear. Past studies have contributed to increasing evidence of multifactorial pathogeneses for both diseases, with the microbiome as a central role in disease pathophysiology. Microbial signatures for Ulcerative Colitis (UC), Crohn’s Disease (CD) and IBS, differing significantly from healthy controls, have been detected. Microbial interactions occurring at the intestinal mucosa, partly impairing epithelial barrier function, are thought to be closely involved in immunologic mechanisms leading to inflammation and disease development. During colonoscopies of a large patient cohort at the Vienna General Hospital, macroscopically visible biofilms were detected in the intestines of IBD and IBS patients. We hypothesize that these biofilms harbor disease-specific polymicrobial signatures and substantially influence disease pathogenesis. METHODS Biofilm samples of UC, IBD-Unclassified (IBD-U) and IBS patients were collected during colonoscopy. DNA of Biofilm and matched stool samples was extracted and polymerase chain reaction (PCR) was performed for fungi, archaea and bacteria. Sequencing with MiSeq Ilumina was conducted and reads were analyzed to detect significant differences in microbial composition of biofilm and stool samples. RESULTS Biofilms are polymicrobial microenvironments consisting of fungi, archaea and bacteria, and biofilm composition resembles the microbiome of matching stool samples concerning fungi and archaea. However, fecal mircrobiomes of patients with and patients without biofilms only show significant differences in archaeal composition. Significant biofilm compositions for disease phenotypes could only be detected when studying bacteria, not for fungi and archaea. Finally yet importantly, a gastric biofilm was studied and revealed high abundance of Streptococcus and Lecanoromycetes. DISCUSSION Endoscopically visible biofilms of the colon are a completely novel finding. In this study, we showed specific shifts in the microbiome of biofilm-positive patients, pointing at gut dysbiosis. The resemblance of biofilms to their matched stool samples shows, that fungi and archaea might be responsible for the development of biofilms. Furthermore, we showed that biofilm composition depends on disease phenotype (IBD vs. IBS), indicating different pathomechanisms. Biofilms might be the first macroscopic alterations detected in IBS and could help to better understand disease pathophysiology of IBD and IBS. However, further studies are needed to evaluate the role of biofilms in the gastrointestinal tract and their impact on IBD and IBS.