BACKGROUND: Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 positively affect the fecal bacteriome in children with celiac disease autoimmunity after 6 months of supplementation. The aim of the present investigation was to study the effects of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 on the single-cell parasitome, with a primary focus on Blastocystis. METHODS: Stool samples were collected from 78 Swedish children with celiac disease autoimmunity participating in a randomized, double-blind, placebo-controlled clinical trial to either receive a mixture of supplementation with L. plantarum HEAL9 and L. paracasei 8700:2 (n = 38) or placebo (n = 40). A total of 227 stool samples collected at baseline and after 3 and 6 months of intervention, respectively, were retrospectively analyzed for Blastocystis by quantitative real-time PCR and subtyped by massively parallel amplicon sequencing. Other single-cell parasites were detected by untargeted 18S rDNA amplicon sequencing and verified by real-time PCR. The relation between the parasites and the bacteriome community was characterized by using 16S rDNA profiling of the V3-V4 region. RESULTS: Three different single-cell protists were identified, of which the highest prevalence was found for Dientamoeba fragilis (23.1%, 18/78 children), followed by Blastocystis (15.4%, 12/78) and Entamoeba spp. (2.6%, 2/78). The quantity of the protists was stable over time and not affected by probiotic intervention (P = 0.14 for Blastocystis, P = 0.10 for D. fragilis). The positivity of the protists was associated with increased bacteriome diversity (measured by multiple indices, P < 0.03). Bacterial composition was influenced by the presence of the protists: positivity of Blastocystis was inversely associated with Akkermansia (at the levels of the genus as well as its family, order, class and phylum); P < 0.002), Faecalibacterium (P = 0.003) and Romboutsia (P = 0.029); positivity of D. fragilis was inversely associated with families Enterobacteriaceae (P = 0.016) and Coriobacteriaceae (P = 0.022) and genera Flavonifractor (P < 0.001), Faecalibacterium (P = 0.009), Lachnoclostridium (P = 0.029), Ruminococcus (P < 0.001) and Granulicatella (P = 0.018). CONCLUSIONS: The prevalence of single-cell protists is low in children with celiac disease autoimmunity. The colonization was stable regardless of the probiotic intervention and associated with increased diversity of the fecal bacteriome but inversely associated with some beneficial bacteria.

• Klíčová slova
• Blastocystis, Celiac disease, Dientamoeba fragilis, Gut microbiome, Probiotics,
• MeSH
• autoimunita MeSH
• Bacteria MeSH
• Blastocystis * genetika   MeSH
• celiakie * MeSH
• dítě MeSH
• dvojitá slepá metoda MeSH
• feces parazitologie   MeSH
• Lacticaseibacillus MeSH
• Lactobacillus paracasei * MeSH
• lidé MeSH
• probiotika * terapeutické užití   farmakologie   MeSH
• retrospektivní studie MeSH
• ribozomální DNA MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH
• Názvy látek
• ribozomální DNA MeSH

INTRODUCTION: Several studies have demonstrated dysbiosis in irritable bowel syndrome (IBS). Therefore, faecal microbiota transplantation, whose effect and safety have been proven in Clostridioides difficile infections, may hold promise in other conditions, including IBS. Our study will examine the effectiveness of stool transfer with artificially increased microbial diversity in IBS treatment. METHODS AND ANALYSIS: A three-group, double-blind,randomised, cross-over, placebo-controlled study of two pairs of gut microbiota transfer will be conducted in 99 patients with diarrhoeal or mixed type of IBS. Patients aged 18-65 will be randomised into three equally sized groups: group A will first receive two enemas of study microbiota mixture (deep-frozen stored stool microbiota mixed from eight healthy donors); after 8 weeks, they will receive two enemas with placebo (autoclaved microbiota mixture), whereas group B will first receive placebo, then microbiota mixture. Finally, group C will receive placebos only. The IBS Severity Symptom Score (IBS-SSS) questionnaires will be collected at baseline and then at weeks 3, 5, 8, 11, 13, 32. Faecal bacteriome will be profiled before and regularly after interventions using 16S rDNA next-generation sequencing. Food records, dietary questionnaires, anthropometry, bioimpedance, biochemistry and haematology workup will be obtained at study visits during the follow-up period. The primary outcome is the change in the IBS-SSS between the baseline and 4 weeks after the intervention for each patient compared with placebo. Secondary outcomes are IBS-SSS at 2 weeks after the intervention and 32 weeks compared with placebo and changes in the number of loose stools, Bristol stool scale, abdominal pain and bloating, anthropometric parameters, psychological evaluation and the gut microbiome composition. ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of Thomayer University Hospital, Czechia (G-18-26); study results will be published in peer-reviewed journals and presented at international conferences and patient group meetings. TRIAL REGISTRATION NUMBER: NCT04899869.

• Klíčová slova
• adult gastroenterology, functional bowel disorders, microbiology,
• MeSH
• dysbióza terapie   MeSH
• fekální transplantace metody   MeSH
• klinické křížové studie MeSH
• lidé MeSH
• mikrobiota * MeSH
• průjem terapie   MeSH
• randomizované kontrolované studie jako téma MeSH
• syndrom dráždivého tračníku * terapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• protokol klinické studie MeSH