The possible role of Shigella in sporadic enteric reactive arthritis.

Reactive arthritis (ReA) occurs after a urogenital infection usually with Chlamydia trachomatis or an enteritis due to Yersinia, Salmonella, Campylobacter or Shigella, Shigella, except during epidemics, is not considered to be a frequent cause of enteric reactive arthritis. However this might be due to the lack of a reliable antibody test, which makes diagnosis difficult. We compared synovial and peripheral blood lymphocyte proliferation to various bacterial antigens in 19 consecutive patients with ReA or undifferentiated oligoarthritis. In five patients Shigella was identified as the causative microbe by a specific synovial lymphocyte proliferation. All five patients had a history of symptomatic diarrhoea and had negative stool cultures by the time arthritis developed. Four of the five were HLA B27 positive. We conclude that Shigella may be underestimated as a cause of non-epidemic ReA.