Decreased Enteric Bacterial Composition and Diversity in South American Crohn's Disease Vary With the Choice of Treatment Strategy and Time Since Diagnosis.

The symptomology of Crohn's disease [CD], a chronic inflammatory disease of the digestive tract, correlates poorly with clinical, endoscopic or immunological assessments of disease severity. The prevalence of CD in South America is rising, reflecting changes in socio-economic stability. Many treatment options are available to CD patients, including biological agents and corticosteroids, each of which offers variable efficacy attributed to host genetics and environmental factors associated with alterations in the gut microbiota. Based on 16S rRNA gene sequencing and taxonomic differences, we compared the faecal microbial population of Brazilian patients with CD treated with corticosteroid or anti-tumour necrosis factor [anti-TNF] immunotherapy. Faecal calprotectin and plasma sCD14 levels were quantified as markers for local and systemic inflammation, respectively. Anti-TNF treatment led to an increased relative abundance of Proteobacteria and a decreased level of Bacteroidetes. In contrast, corticoid treatment was associated with an increase in the relative abundance of Actinobacteria, which has been linked to inflammation in CD. Disruption of the faecal microbiota was related to decreased bacterial diversity and composition. Moreover, the choice of clinical regimen and time since diagnosis modulate the character of the resulting dysbiosis. Enteric microbial populations in CD patients who have been treated are modulated by disease pathogenesis, local inflammatory microenvironment and treatment strategy. The dysbiosis that remains after anti-TNF treatment due to decreased bacterial diversity and composition abates restoration of the microbiota to a healthy state, suggesting that the identification and development of new clinical treatments for CD must include their capacity to normalize the gut microbiota.

Cruz-Lebrón A ，D'argenio Garcia L ，Talla A ，Joussef-Piña S ，Quiñones-Mateu ME ，Sékaly RP ，de Carvalho KIL ，Levine AD ... -  《-》

IL23R-Protective Coding Variant Promotes Beneficial Bacteria and Diversity in the Ileal Microbiome in Healthy Individuals Without Inflammatory Bowel Disease.

This study aimed to characterize the mucosa-associated microbiota in ileal Crohn's disease [CD] patients and in healthy controls in terms of host genotype and inflammation status. The mucosa-associated microbiotas of intestinal pinch biopsies from 15 ileal CD patients with mild and moderate disease and from 58 healthy controls were analysed based on 16S ribosomal sequencing to determine microbial profile differences between [1] IL23R, NOD2 and ATG16L1 genotypes in healthy subjects, [2] ileal CD patients and control subjects, and [3] inflamed and non-inflamed mucosal tissue in CD patients. The protective variant of the IL23R gene [rs11209026] significantly impacted the microbial composition in the ileum of healthy subjects and was associated with an increased abundance of phylotypes within the family Christensenellaceae as well as increases in diversity and richness. Comparative analysis of healthy and non-inflamed CD microbiome samples indicated a notable decrease in the abundance of Faecalibacterium prausnitzii as well as Shannon diversity and richness. Inflamed and non-inflamed ileal samples of CD subjects had high intra-individual stability and inter-individual variability, but no significant alterations in diversity, richness or taxa were identified. Calprotectin correlated positively with the abundance of Proteobacteria and negatively with diversity in the samples from healthy subjects. The observation of low diversity and low abundance of beneficial bacteria in healthy control subjects carrying the IL23R [rs11209026] wild-type GG genotype indicates that the gut microbiome is influenced by host genetics and is altered prior to disease diagnosis. Faecal calprotectin may be a potential non-invasive screening tool for dysbiosis in subjects without disorders of intestinal inflammation.

Zakrzewski M ，Simms LA ，Brown A ，Appleyard M ，Irwin J ，Waddell N ，Radford-Smith GL ... -  《-》

Does the intestinal microbial community of Korean Crohn's disease patients differ from that of western patients?

Eun CS ，Kwak MJ ，Han DS ，Lee AR ，Park DI ，Yang SK ，Kim YS ，Kim JF ... -  《BMC GASTROENTEROLOGY》

Modulation of faecal metagenome in Crohn's disease: Role of microRNAs as biomarkers.

Rojas-Feria M ，Romero-García T ，Fernández Caballero-Rico JÁ ，Pastor Ramírez H ，Avilés-Recio M ，Castro-Fernandez M ，Chueca Porcuna N ，Romero-Gόmez M ，García F ，Grande L ，Del Campo JA ... -  《-》

Characteristics of Faecal Microbiota in Paediatric Crohn's Disease and Their Dynamic Changes During Infliximab Therapy.

Crohn's disease [CD] is known to be associated with gut microbial dysbiosis. Infliximab [IFX] is increasingly used to treat paediatric CD; however, it is not clear how the gut microbiota is modified during IFX treatment. The aim of this study was to characterise the faecal microbiota community composition in paediatric CD patients and to assess its dynamic changes during IFX therapy. A 16S rRNA sequencing approach was applied to determine the compositions of microbial communities in faecal samples. The composition and function of the faecal microbiota were compared between CD patients and healthy controls. Characteristics of faecal microbiome composition in paediatric CD patients before IFX treatment were represented by a lower biodiversity, a gain in Enterococcus, and a significant loss in multiple short-chain fatty acid [SCFA]-producing bacteria, including Anaerostipes, Blautia, Coprococcus, Faecalibacterium, Lachnospira, Odoribacter, Roseburia, Ruminococcus, and Sutterella. Additionally, alterations were observed in metabolic functions of the gut microbial community in CD. IFX treatment increased the biodiversity of gut microbiota and shifted its composition as well as its functional capabilities in the paediatric CD patients toward a healthy status. However, multiple SCFA-producing taxa were not significantly expanded. The sustained response of paediatric CD patients to IFX was associated with abundance of SCFA-producing bacteria. A lower biodiversity with alterations in the composition and function of faecal microbial community, characterising gut microbial dysbiosis, was observed in Chinese paediatric CD patients. IFX diminished the CD-associated gut microbial dysbiosis but was deficient in increasing certain SCFA-producing taxa.

Wang Y ，Gao X ，Ghozlane A ，Hu H ，Li X ，Xiao Y ，Li D ，Yu G ，Zhang T ... -  《-》