Somatic serogroups, capsular types, and species of fecal Klebsiella in patients with ankylosing spondylitis

The purpose of the present study was to find out whether patients with anky losing spondylitis (AS) carry fecal Klebsiella strains that belong to serot ypes or species specific for AS. Somatic serotypes (O groups), capsular (K) serotypes, and biochemically identified species were determined for fecal klebsiellae isolated from 187 AS patients and 195 control patients. The con trols mere patients with fibromyalgia or rheumatoid arthritis. The 638 isol ates of Klebsiella that were obtained represented 161 strains; 81 from AS p atients and 80 from the controls. The average number of Klebsiella strains per patient was 1.7 for the AS group and 1.5 for the control group. The mos t common O group was O1, which was observed for isolates from 23 of 187 AS patients and 24 of 195 control patients. Next in frequency was group O2, wh ich was observed For isolates from 17 AS patients and 15 control patients. Regarding the K serotypes, 59 different types were identified, revealing a heterogeneous representation of Klebsiella strains, without a predominance of any serotype. By biochemical identification, Klebsiella pneumoniae was t he most frequently occurring species, being found in 45 AS patients and 45 control patients. Next in the frequency was K. oxytoca, which was observed in 26 AS patients and in 29 control patients. K. planticola and K. terrigen a occurred in only a minority of patients. Altogether, when analyzed either separately or simultaneously according to O groups, K serotypes, and bioch emically identified species, no evidence of the existence of AS-specific Kl ebsiella strains was obtained. These findings do not indicate participation of Klebsiella in the etiopathogenesis of AS.