Comparison of faecal florae in patients with rheumatoid arthritis and controls.

The faecal flora of 25 out-patients with active rheumatoid arthritis (RA) was compared with that of 25 age- and sex-matched controls. A comprehensive survey revealed a significantly higher carriage rate of Clostridium perfringens in the RA population (88%) than controls (48%) (p less than 0.01). Coliform counts also tended to be higher, but there were no other significant differences between patients and controls. When the study was enlarged to include a further 113 RA patients with variable disease activity and a further 38 controls, clostridia were again more frequently carried by those with RA (70%) than controls (45%) (p less than 0.01) and clostridial counts were significantly higher in the patient group (p = 0.006). Moreover, counts in patients with active or moderately active disease were significantly higher than in those with inactive disease (p less than 0.001). These data are consistent with the hypothesis that Cl. perfringens plays a role in triggering or is otherwise associated with disease activity in RA. The findings may be alternatively an effect of the disease or its treatment with, for example, anti-inflammatory drugs.