The Degree of Mucosa-Associated Microecological Imbalance in Ulcerative Colitis Patients with Different Mayo Score and Its Relationship with Mucosal Mechanical Barrier Damage.

Patients with severe UC exhibited elevated abundance indexes and increased numbers of phyla compared to patients with mild or moderate UC.

• Bacterial and fungal populations were analyzed using Illumina MiSeq sequencing in UC patients and healthy controls
• Severe UC patients showed increased numbers of phyla and higher proportions of specific phyla including Actinobacteria, Acidobacteria, Chloroflexi, Gemmatimonadetes, Nitrospirae, and an unclassified phylum
• Disease severity was defined using the Mayo score
• Analysis focused on changes in diversity of bacteria and fungi along with their distribution at phylum and genus levels

The proportions of dominant bacterial phyla (Firmicutes, Bacteroidetes, and Proteobacteria) displayed an inverse relationship with UC severity.

• As UC severity increased according to Mayo score, proportions of these three dominant phyla decreased
• This inverse relationship was observed across mild, moderate, and severe UC categories
• The finding suggests a shift away from dominant commensal bacteria as disease severity progresses

Moderate and severe UC cases showed a greater prevalence of negative fungal genera compared to mild cases.

• Fungal microbiota composition was analyzed alongside bacterial microbiota using Illumina MiSeq sequencing
• The difference in negative genera prevalence was specifically noted between mild UC and moderate-to-severe UC cases
• This finding indicates that fungal dysbiosis also worsens with increasing UC severity

Changes in microflora composition were associated with the extent of mucosal mechanical barrier damage.

• The potential relationship between microecological imbalance and damage to the mucosal mechanical barrier was assessed
• Both bacterial and fungal microbiota changes were evaluated in the context of mucosal barrier integrity
• The association suggests that mucosa-associated microecological imbalance may contribute to disruptions in the intestinal mucosal mechanical barrier

UC is characterized by dysbiosis of gut microbiota alongside mucosal inflammation, and the association between mucosa-related microecological imbalance and UC severity is a crucial aspect of the disease's pathogenesis.

• UC is described as a chronic inflammatory bowel disease known for mucosal inflammation and dysbiosis of gut microbiota
• The study investigated the relationship between mucosa-related microecological imbalance and different levels of UC severity as defined by Mayo score
• Both bacterial and fungal populations of mucosa-associated microbiota were analyzed