Gut microbiota differences between psoriatic arthritis and other undifferentiated arthritis: A pilot study.

None of the available objective clinical laboratory data could differentiate PSA group from the NO PSA subgroup. The microbiota result shows that Family: XIII_AD3011 is significantly higher in NO PSA patients' than in PSA patients' stool samples (P = .039). Megasphaera elsdenii in the PSA group was 10,000 times higher than in the NO PSA group.Our results demonstrated high intragroup homogeneous and high intergroup heterogeneous microbiota. The clinical symptoms of either enthesitis or dactylitis are associated with higher presence of specific microbiota in the current study. The PSA and other undifferentiated arthritis could be differentiated with microbiota analysis. In the future, a larger cohort and thorough biochemical study are needed for confirmation.The microbiota is different between PSA and NO PSA patients, and the species could be used as a differential diagnostic tool between these 2 diseases. The clinically available serum markers may not be enough to reflect the details of patients with different patterns of arthritis. Megasphaera elsdenii species could be a link between gut flora and enthesitis and/or dactylitis clinically in PSA. We confirm the fact that the Bifidobacterium longum correlates negatively with eosinophils.