Lo Presti A¹, Zorzi F², Del Chierico F³, Altomare A⁴, Cocca S⁴, Avola A⁴, De Biasio F⁴, Russo A³, Cella E⁵, Reddel S³, Calabrese E², Biancone L², Monteleone G², Cicala M⁴, Angeletti S⁶, Ciccozzi M⁵, Putignani L⁷, Guarino MPL⁴. Front Microbiol. 2019 Jul 17;10:1655. doi: 10.3389/fmicb.2019.01655. eCollection 2019.

Author information

1 Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.

2 Gastrointestinal Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.

3 Human Microbiome Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.

4 Unit of Digestive Disease, Campus Bio-Medico University, Rome, Italy.

5 Unit of Medical Statistics and Molecular Epidemiology, Campus Bio-Medico University, Rome, Italy.

6 Unit of Clinical Laboratory Science, Campus Bio-Medico University, Rome, Italy.

7 Human Microbiome Unit and Parasitology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.

Abstract

An imbalance in the bacterial species resulting in the loss of intestinal homeostasis has been described in inflammatory bowel diseases (IBD) and irritable bowel syndrome (IBS). In this prospective study, we investigated whether IBD and IBS patients exhibit specific changes in richness and distribution of fecal and mucosal-associated microbiota. Additionally, we assessed potential 16S rRNA gene amplicons biomarkers for IBD, IBS, and controls (CTRLs) by comparison of taxonomic composition. The relative abundance of bacteria, at phylum and genus/species levels, and the bacterial diversity were determined through 16S rRNA sequence-based fecal and mucosal microbiota analysis. Linear discriminant analysis effect size (LEfSe) was used for biomarker discovery associated to IBD and IBS as compared to CTRLs. In fecal and mucosal samples, the microbiota richness was characterized by a microbial diversity reduction, going from CTRLs to IBS to IBD. β-diversity analysis showed a clear separation between IBD and CTRLs and between IBD and IBS with no significant separation between IBS and CTRLs. β-diversity showed a clear separation between mucosa and stool samples in all the groups. In IBD, there was no difference between inflamed and not inflamed mucosa. Based upon the LEfSe data, the Anaerostipes and Ruminococcaceae were identified as the most differentially abundant bacterial taxa in CTRLs. Erysipelotrichi was identified as potential biomarker for IBS, while Gammaproteobacteria, Enterococcus, and Enterococcaceae for IBD. This study provides an overview of the alterations of microbiota and may aid in identifying potential 16S rRNA gene amplicons mucosal biomarkers for IBD and IBS.