Yersinia infection and acute abdominal pain.

In 194 patients presenting with acute abdominal pain from whom sequential serum samples were taken, the frequency of yersiniosis, established serologically, was significantly higher (23%) than in 320 control subjects (2%). Yersiniosis occurred in 31% of patients with acute appendicitis. Acute-phase serum samples only, obtained in a further 307 patients, yielded a falsely low frequency of yersiniosis (4%). Y pseudotuberculosis was five times more common than Y enterocolitica, and Y pseudotuberculosis type IV was the most common serotype, accounting for 43% of Yersinia infections. Yersinia may play a more important part in the aetiology of acute abdominal pain, and particularly acute appendicitis, than has been previously appreciated. Antibody titres to both Y enterocolitica and Y pseudotuberculosis frequently rise late in infections causing abdominal pain. Consequently analysis of acute-phase serum samples alone leads to underdiagnosis of yersiniosis.