ASSOCIATION BETWEEN CLINICAL PRESENTATION, BIOGROUPS AND VIRULENCE ATTRIBUTES OF YERSINIA-ENTEROCOLITICA STRAINS IN HUMAN DIARRHEAL DISEASE

Traditionally the enteric pathogen Yersinia enterocolitica has been di fferentiated into biogroups. Despite being considered as non-pathogeni c, biogroup 1A isolates have constituted a sizeable fraction of strain s from patients with gastroenteritis in many reports. To establish a p otential clinical significance for biogroup 1A isolates of Y. enteroco litica, clinical disease in patients with gastroenteritis excreting su ch isolates was compared with symptoms among patients found infected w ith pathogenic biogroups. Clinical data and isolates of 66 patients fr om whom Y. enterocolitica had been isolated by direct plating were ava ilable for study. There was an association between patient age below 3 years and infection with 'pathogenic' Y. enterocolitica. The severity of gastroenteritis and other symptoms, however, did not depend on the biogroup, or the presence of the virulence plasmid in the yersinia st rain isolated from the patients. Strains belonging to biogroup 1A of Y . enterocolitica showed two clusters of ribotypes, one of which encomp assed most isolates recovered from humans, the other being associated with environmental isolates. This might indicate the existence of huma n-adapted and potentially pathogenic strains among biogroup 1A of Y. e nterocolitica.