Abstracts Division 2

31. Gut microbiota perturbations precede the onset of Post-Infectious IBS in intercontinental travelers

Jiyang Chan1, Gianluca Galazzo1, 2 (shared first author), Markia Ward2, Maris Arcilla3, Perry van Genderen4 and John Penders1, 2 on behalf of the COMBAT-consortium

1 School of Nutrition and Translational Research in Metabolism (NUTRIM), Department of Medical Microbiology, Maastricht University Medical Centre, Maastricht, the Netherlands
2 School for Public Health and Primary Care (Caphri), Department of Medical Microbiology, Maastricht University Medical Centre, Maastricht, the Netherlands
3 Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Centre, Rotterdam, Netherlands
4 Institute for Tropical Diseases, Havenziekenhuis, Rotterdam, Netherlands

A proportion of Irritable Bowel Syndrome (IBS) patients report the onset of symptoms after infectious gastroenteritis (IG), denoted as post-infectious IBS (PI-IBS). To what extent microbiota alterations precede or are a consequence of the infectious episode remains undescribed. We prospectively characterized the faecal microbiota diversity, community structure and dynamics in Dutch intercontinental travellers with and without PI-IBS development after travellers’ diarrhoea.

We conducted a nested case-control study within a longitudinal cohort among travellers. Cases were defined as healthy travellers (without gastrointestinal symptoms at baseline) who experienced diarrhoea during the index travel and met the ROME III criteria for IBS at 6-12 months after travel return. For each case, we matched one control based on age, gender and travel destination. Faecal samples collected pre-travel, immediately post-travel and 1-month post-travel were profiled by 16S rRNA gene amplicon sequencing to examine the microbial diversity, composition and community structure.

53 subjects met our case definition for PI-IBS and were matched to 53 control subjects. Microbial richness prior to the onset of PI-IBS was significantly lower in future cases compared to controls (p=0.0028). The microbial diversity (Shannon-index) was also lower in PI-IBS cases before and immediately after travel (p=0.0338 and p=0.0105 respectively). In addition, the microbial community structure of PI-IBS cases was significantly different as compared to healthy controls pre-travel, immediately after travel and one-month post-travel (PERMANOVA p< 0.05 for all time-points). Longitudinal differential abundance testing indicated increased levels of Bacteroides and Streptococcus in PI-IBS cases compared to a higher abundance of Ruminococcus and Butyricoccus among healthy controls.

In a longitudinal study of faecal microbiota of intercontinental travellers from pre-travel through post-travel, we identified an altered microbiota profile preceding the onset of PI-IBS. These results strengthen the evidence for a causal role of the microbiota in the pathophysiology of IBS.

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NUTRIM aims to contribute to health maintenance and personalised medicine by unraveling lifestyle and disease-induced derangements in metabolism and by developing targeted nutritional, exercise and drug interventions. This is facilitated by a state of the art research infrastructure and close interaction between scientists, clinicians, master and PhD students.