P738 Disease activity related dysbiosis in inflammatory bowel disease patients
M. E. Grasman*1, R. J. van der Borden1, A. E. Budding2, A. Eck2, N. K. de Boer1, G. Bouma1, P. H. Savelkoul2, A. A. van Bodegraven1
1VU University Medical Centre, Gastroenterology and Hepatology, Amsterdam, Netherlands, 2VU University Medical Centre, Medical Microbiology and Infection control, Amsterdam, Netherlands
Composition of the intestinal microbiota is critical in understanding the pathogenesis of inflammatory bowel disease (IBD). Differences in microbial composition between patients with Crohn’s disease (CD) and ulcerative colitis (UC) have been reported. Less is known about disease activity specific alterations. Therefore, microbiota analysis was used to assess its diagnostic potential in IBD patients in an outpatient clinical setting.
Rectal swabs were collected from consecutive IBD patients at a referral, third-line IBD outpatient clinic. Disease activity was determined with standard clinical indices. Rectal swabs were analysed with IS-pro, based on the 16S-23S interspacer ribosomal RNA gene, enabling extensive characterisation of the most prominent intestinal bacterial phyla: Bacteroidetes, Firmicutes, Actinobacteria, Fusobacteria, Verrucomicrobia (FAFV), and Proteobacteria. Differences in abundance and diversity and its related phylum-phylum ratios between disease type and disease activity were determined. Cross-validated partial least squares discriminant analysis (PLS-DA) was used to assess the potential for microbiota-based clinical prediction models.
Rectal swabs from 134 consecutive patients were collected (CD n = 80; UC n = 54). Half of CD patients and one-third of UC patients had active disease. No differences in abundance or diversity were observed between CD and UC. Active CD and active UC were associated with decrease of abundance and diversity of Proteobacteria. In active CD, loss of bacterial species and abundance in Bacteroidetes phylum were observed. Both in active CD and UC, the total species diversity and abundance were lower. FAFV/Bacteroidetes abundance and diversity ratio was higher in quiescent UC as compared with quiescent CD. This was not observed in active disease. FAFV/Proteobacteria abundance and diversity ratio were higher in active disease, irrespective of disease type. For FAFV/Bacteroidetes abundance and diversity ratios, this was only found in CD. No single species was associated with disease type or degree of activity. In these relatively small series, accuracy to separate active from quiescent CD was 60% and 66% in Bacteroidetes, and when all phyla were combined, respectively.
Analysing rectal swabs with IS-pro is a feasible method for microbiota determination in an outpatient clinical setting. Disease-activity related dysbiosis was observed, especially in CD, which potentially enables diagnostic application, especially in an IBD outpatient setting.
- Posted in: Poster presentations: Microbiology (2016)