Causative role of Yersinia and other enteric pathogens in the appendicular syndrome.

In 2,861 consecutive patients undergoing appendicectomy for clinically suspected appendicitis an enteric pathogen was isolated from the appendix in almost 7% using an optimal combination of culture media. The pathogenic Yersinia enterocolitica serotypes 03 and 09 predominated (3.6%), followed by Campylobacter and nontyphoid Salmonella. The same pathogen was isolated from the stool in 72.5% of patients with a culture-positive appendix and in 84.1% of those positive for a pathogenic Yersinia. Conversely, no pathogenic Yersinia were isolated in 326 gynaecologic control patients, in whom a normal appendix was removed. No frank appendicitis but mesenteric adenitis and/or terminal ileitis were found in 62.3% of 138 patients with a culture positive appendix, and in 74.6% of those positive for a pathogenic Yersinia. Histologic findings available in 135 patients showed acute suppurative appendicitis in only six (4.5%) patients, and in only one of 73 (1.4%) positive for a pathogenic Yersinia. In contrast, 46.8% of a group of 345 culture-negative appendices showed acute inflammation. A positive stool culture in a patient with suspected appendicitis, if consistent with sonographic and clinical findings, should be taken as strong evidence against the presence of true appendicitis.