Table 2.

Examples of studies reporting effects of Parabacteroides distasonis (PD) on intestinal health

Disease	Study Model	Study Design	Clinical Effect
Familiar Mediterranean Fever99 Inflammation	Human blood serum and fecal samples. ELISA analysis of varying antibodies that correspond to different bacterial antigens in both FMF patients and healthy controls. DNA extraction was performed with Wizard Genomic DNA Purification kit and sequencing of the 16S rRNA performed with regions V1, V2, V3.	PD, along with other common gut flora, elicited an enhanced nonspecific humoral response to nonspecific antigens present on bacteria in the presence of FMF.	Aggravator
Colorectal cancer86 Cancer/Inflammation	Six-week-old male A/J mouse models treated with different chow diets laced with PD.	Increase in colonic IL-10, TGF-β β and tight junction proteins Zonula occludens and occludin expression in mouse models given the PD long term in comparison to the control diet. Results support a protective role of PD in colonic tumorigenesis.	Protective
Colorectal cancer100 Cancer/Inflammation	6-w-old male A/J mice fed low-fat (LF) diet, high-fat (HF) diet or a HF + whole freeze-dried PD diet (HF + Pd). Mice received 4 weekly injections of azoxymethane after 1 week on diet. PD analyzed with 16s rRNA gene sequencing.	PD membrane fraction (PdMB) largely suppressed production of pro-inflammatory cytokines, lowered MyD88 and pAkt abundance, and induced apoptosis in colon cancer cell lines, suggesting anti-inflammatory and anti-cancer effects.	Protective
Colitis84 Inflammation	Murine Model of 2,4,6-Trinitrobenzenesulfonic Acid (TNBS)-Induced Colitis based on BALB/C ByJ mice. PD sequenced using V3-V4 16s rRNA regions.	PD reinforces the gut barrier and promotes pro-anti-inflammatory profile. This has a positive association with reducing colitis in tested mouse models. In vitro benefits relied heavily reliant on the strain.	Protective
Colitis17 Inflammation	DSS-induced BALB/c mice – oral treatment of PD. PD analyzed via 16s rRNA sequencing.	PD membrane components decreases the severity of gut inflammation in the non-immunocompromised mouse models that had induced acute and chronic colitis. Also, increased PD serum antibodies and decreased pro-inflammatory cytokines.	Protective
Colorectal carcinogenesis101 Cancer/Inflammation	Shotgun metagenomic sequencing analysis between feces of wild-type mice and mice with defects in TGFB signaling. Analysis of microbiota changes prior to colon tumors development. Shotgun metagenomics sequencing was performed using 150 BP, pair-ended sequences through Illumina sequencing.	PD abundance decreased when there were defects in transformation growth factor beta (TGFB) signaling pathway in mouse models. TGFB-deficient mice have more colorectal cancer and lower PD abundance.	Protective
Crohn’s Disease and Ulcerative Colitis89 Inflammation	WT and antibiotic-depleted intestinal microflora mouse models. Pyrosequencing was performed on the variable regions of bacterial 16s rRNA. The sequences were classified with GreenGenes and compared with using QIIME.	Low PD abundance in patients with CD and UC. Higher PD abundance in gut microbiota of the Pglyrp-deficient mouse models promote colitis.	Aggravator