The role of infections with Yersinia pseudotuberculosis and Yersinia enterocolitica in the pathogenesis of chronic inflammatory, rheumatic and collagen diseases.

From 50 cases of polyarthritis with febrile onset, 3 were found with serum positive Yersinia pseudotuberculosis (YPT) at a titer higher than 1/100. Reactive polyarthritis with gram-negative germs (YPT) serologic type I, involved in their etiology have been rarely encountered especially in North Europe and in the Far East. Though the 3YPT positive cases mentioned above, presented on admission particularly severe forms of joint inflammation, under therapy with Tetracycline and Phenylbutazone derivatives the articular inflammations were cured without relapses in the 6 months of investigations.