A sequential study of the relationship between faecal Klebsiella aerogenes and the common clinical manifestations of ankylosing spondylitis.

An 8-month sequential study at 4-weekly intervals of faecal Klebsiella aerogenes and clinical activity of ankylosing spondylitis is described. Similar frequencies of faecal K. aerogenes were found in the 44 patients and 36 healthy controls studied. Eighteen patients on 19 occasions had K. aerogenes cultured from their faeces, when the preceding specimen had been negative. Six (31.6%) of these occasions were associated with a deterioration in clinical state compared with a similar deterioration associated with only 17 (9.8%) of the remaining 174 faecal culture sequences (p less than 0.02). These results suggest that clinical deterioration in ankylosing spondylitis may be associated with the acquisition of faecal K. aerogenes.