title: Blastocystis is associated with decrease of fecal microbiota protective bacteria: comparative analysis between patients with irritable bowel syndrome and control subjects.
abstract: Blastocystis is a protistan parasite living in the digestive tract of many animals, including humans. This highly prevalent intestinal parasite is suspected to be linked to Irritable Bowel Syndrome (IBS), a chronic functional bowel disorder. Here, we first compared the prevalence of Blastocystis among 56 IBS patients (40 IBS with constipation (IBS-C), 9 IBS with diarrhea (IBS-D), 4 mixed IBS (IBS-M) and 3 unsubtyped IBS (IBS-U) according to the Rome III criteria) and 56 control (i.e. without any diagnosed chronic or acute gastrointestinal disorder) subjects. The highest prevalence of Blastocystis spp. was observed in the IBS group, but was only statistically significant in men (36.8% in the IBS group versus 4.8% in the control group). We then conducted a meta-analysis including epidemiological studies attempting to determine whether Blastocystis carriage could be linked to IBS, and highlighted that IBS patients had a relative risk of 2.34 to be infected by Blastocystis when compared to non-IBS subjects. We also looked for Dientamoeba fragilis, which is often associated with IBS, and identified this parasite only in some IBS patients (n = 6/56). Several studies provided evidence for a major role of the gut microbiota in the pathophysiology of IBS. Thus, we investigated the possible impact of Blastocystis carriage on the enteric bacterial community through quantification of 8 major bacterial groups from the enteric flora. Our data indicated that men with IBS-C had a significant decrease in Bifidobacterium sp. when infected by Blastocystis. Interestingly, in control subjects (i.e. without any gastrointestinal disorder) positive for Blastocystis, Faecalibacterium prausnitzii, which is known for its anti-inflammatory properties, was significantly decreased in men. Our results support the hypothesis that Blastocystis might be linked to the pathophysiology of IBS-C and intestinal flora imbalance.
authors.affiliation: CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Parasitologie-Mycologie, Hôpital G. Montpied, Clermont-Ferrand, France; Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes: Génome et Environnement, BP 10448, Clermont-Ferrand, France; CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Nourrisson
authors.affiliation: CHU Clermont-Ferrand, Service de Médecine digestive et hépatobiliaire, Hôpital Estaing, Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, UMR 1107 INSERM, Neuro-Dol, Clermont-Ferrand, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Scanzi
authors.affiliation: CHU Clermont-Ferrand, DRCI, 'Délégation Recherche Clinique et Innovation', Clermont-Ferrand, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Parasitologie-Mycologie, Hôpital G. Montpied, Clermont-Ferrand, France.
authors.forename: Christina
authors.initials: C
authors.lastname: NkoudMongo
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes: Génome et Environnement, BP 10448, Clermont-Ferrand, France; CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Wawrzyniak
authors.affiliation: Université Lille Nord de France, INSERM U1019, CNRS UMR 8204, Centre d'Infection et d'Immunité de Lille (CIIL), Institut Pasteur, Biologie et Diversité des Pathogènes Eucaryotes Emergents, Lille, France.
authors.forename: Amandine
authors.initials: A
authors.lastname: Cian
authors.affiliation: Université Lille Nord de France, INSERM U1019, CNRS UMR 8204, Centre d'Infection et d'Immunité de Lille (CIIL), Institut Pasteur, Biologie et Diversité des Pathogènes Eucaryotes Emergents, Lille, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Viscogliosi
authors.affiliation: CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Parasitologie-Mycologie, Hôpital G. Montpied, Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, 'Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne U1071 USC-INRA 2018, BP 10448, Clermont-Ferrand, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Livrelli
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes: Génome et Environnement, BP 10448, Clermont-Ferrand, France; CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Delbac
authors.affiliation: CHU Clermont-Ferrand, Service de Médecine digestive et hépatobiliaire, Hôpital Estaing, Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, UMR 1107 INSERM, Neuro-Dol, Clermont-Ferrand, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Dapoigny
authors.affiliation: CHU Clermont-Ferrand, Centre de Biologie, Laboratoire de Parasitologie-Mycologie, Hôpital G. Montpied, Clermont-Ferrand, France; Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes: Génome et Environnement, BP 10448, Clermont-Ferrand, France; CNRS, UMR 6023, LMGE, Aubière, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Poirier
mesh_terms: D000328:Adult; D000368:Aged; D016844:Blastocystis / Q000382:microbiology*; D016776:Blastocystis Infections / Q000382:microbiology*; D005243:Feces / Q000382:microbiology / Q000469:parasitology; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000382:microbiology / Q000469:parasitology; D008297:Male; D064307:Microbiota; D008875:Middle Aged