Yersinia Enterocolitica: A Panoramic View of a Charismatic Microorganism

Yersinia enterocolitica, a small, Gram-negative coccobacillus which culturally and biochemically resembles members of the family Enterobacteriaceae, is widespread in nature, particularly in both domestic and wild mammals and birds. Human infection caused by this microorganism has been well documented in Europe, primarily in Scandinavian countries, and is now being increasingly appreciated in the United States, Canada, South Africa, and Japan. Infection with Y. enterocolitica usually presents as acute mesenteric lymphadenitis and terminal ileitis, although gastroenteritis, erythema nodosum, polyarthritis, septicemia, meningitis, cellulitis, conjunctivitis, and subacute localized abscesses in liver and spleen have also been recorded. Beginning with a review of historical milestones since its first description in the U.S. in 1939, this article will endeavor to place into perspective those factors contributing to the recognition and awareness in the U.S. of this long-discounted human pathogen. Pertinent to the discussion will be a consideration of nomenclature and taxonomy, microscopic morphology, and isolation techniques (including cold enrichment and appropriate media and cultural, biochemical, and serological factors enabling proper identification and differentiation of Yersinia from other Enterobacteriaceae). Clinically, the myriad symptomatologies encountered in infections caused by Yersinia enterocolitica will be discussed along with epidemiologic consideration.