Observations on the action of strains of Yersinia enterocolitica from various sources on Hep-2 cells and human foetal gut.

Forty-five strains of Y enterocolitica including eleven from ankylosing spondylitis patients were examined for their ability to invade Hep-2 cells in culture. Nineteen out of twenty pathogenic strains were invasive and the rest were non-invasive. Three pathogenic strains were invasive, and three non-pathogenic strains were not invasive to human foetal gut. Invasiveness was not found to be useful for differentiating ankylosing spondylitis from non-ankylosing spondylitis strains.