Abnormalities in the proportion of anti-inflammatory strains may represent a potential target for therapy.
Previous investigators have found abnormalities in the composition of the intestinal microbiota of patients with spondyloarthritis (SpA).
In this study, Stoll and colleagues1 at the University of Alabama at Birmingham obtained fecal specimens from 30 children with treatment-naive enthesitis-related arthritis (ERA) and 19 healthy controls, as well as specimens from 11 adults with longstanding SpA and 10 healthy controls. All specimens underwent DNA sequencing, and shotgun metagenomics sequencing was performed on some of the fecal samples from children.
• Children with ERA had a decreased proportion of the anti-inflammatory Faecalibacterium prausnitzii A2-165 strain (41 ± 28% vs 54 ± 20% of all sequences matching F prausnitzii; P = .084).
• Adults with SpA had a similarly reduced proportion of the F prausnitzii A2-165 strain.
• The proportion of fecal Bacteroides fragilis was increased in children with ERA (2.0 ± 4.0% vs 0.45 ± 0.7% of all sequences; P = .045).
• In adults with SpA, the proportion of fecal B fragilis was diminished (0.2 ± % vs 1.0 ± % of all sequences, P = .106).
• In children with ERA, shotgun metagenomics sequencing of the fecal DNA demonstrated reduced coverage of the butanoate pathway (abundance normalized to controls of 1 ± 0.48 vs 0.72 ± 0.33 in ERA, P = .037)
Implications for clinicians
• Reduced levels of F prausnitzii may have an adverse effect on intestinal health because of the resulting decrease in the production of butyrate and other short chain fatty acids.
• "Our study supports previous work indicating that decreased fecal abundance of a regulatory strain of Fprausnitzii may be at least partly responsible for the pathogenesis of SpA, possibly due to decreased production of butyrate," the researchers conclude.
• They suggest that replenishing butyrate levels in patients with SpA may represent a potential treatment.
1. Stoll ML, Weiss PF, Weiss JE, et al. Age and fecal microbial strain-specific differences in patients with spondyloarthritis. Arthritis Res Ther. 2018;20:14. doi:10.1186/s13075-018-1510-6.