Yersinia Yersinia enterocolitica (1976) is a gram-negative organism that only recently has become known to infect man. Although the number of infections with Yersiniia entercolitica has increased during the last few years, most  reports came from Europe, Africa, Australia, and Japan. During the past year, Yersinia infections have been discovered in Canada  and in the United States. Most diseases caused by Yersinia entercolitica are relatively benign; however, we have recently observed one case that presented as a severe abscess of the lung. This case is unique in that it is not only the first report of pulmonary disease with this organism, but also demonstrates the potential aggressiveness of this organism in areas outside the gastrointestinal tract. Our purpose is to report this unusual occurrence and to acquaint the physician with this organism and some of its manifestations. CLINICAL MANIFESTATIONS: Yersinia enterocolitica and Yersinia pseudotuberculosis cause several age-specific syndromes and a variety of uncommon presentations. The most common manifestation of infection with Y enterocolitica is enterocolitis with fever and diarrhea; stool often contains leukocytes, blood, and mucus. This syndrome occurs most often in young children. A pseudoappendicitis syndrome (fever, abdominal pain, tenderness in the right lower quadrant of the abdomen, and leukocytosis) occurs primarily in older children and young adults. Focal infections, abscess formation (such as hepatic and splenic), and bacteremia occur most often in patients with predisposing conditions, such as excessive iron storage. Other manifestations of infection are uncommon and include pharyngitis, meningitis, osteomyelitis, pyomyositis, conjunctivitis, pneumonia, acute proliferative glomerulonephritis, peritonitis, and primary cutaneous Of 187 newborns admitted to a 33-bed, level III neonatal intensive care unit between January 1, 1985 and June 23, 1985, 33 developed necrotlzlng enterocolitis during their hospital stay. Twenty of the 33 newborns (61%) had onset of symptoms between April 1 and June 23, suggesting clustering during this period. A case-control study, with matching on birth weIght class, approximate date of admission to the unit and approximate duration of stay, failed to reveal any association of the syndrome with type or timing of feeding, perinatal hypoxic events, as determined by apgar scores and labor history, or specific microbial organisms. By contrast, however, transfusion of packed red blood cells was highly and significantly associated with the syndrome (odds ratio = 15.1, 95% confidence interval = 2.59–92.51). In addition, therapy with caffeine, with theoph ylline, and with furosemide were moderately associated with the syndrome, although not significantly so. During this outbreak period, the Incidence of necrotizing enterocolitis by birth weight was 30.6% in infants less than 1,500 gm, 10.8% in infants 1,500–2,500 gm, and 11.9% in infants 2,500 gm or more. These findings confirm the importance of low birth weight as a risk factor for development of the syndrome and suggest that Insults to volume homeostasis, such as transfusion and use of diuretics, need to be considered as possible mechanisms whereby necrotizing enterocolitis is Initiated. The authors report (1993) a rare case of Yersinia enterocolitica necrotizing pneumonia in an immunocompromised patient, who responded with resolution of the infection after 6 weeks of therapy with a third-generation cephalosporin but subsequently expired from the underlying lymphoma. In the few cases of Y. enterocolitica pulmonary infections that have been reported, the prognosis for cure of the infection is excellent with appropriate antibiotic therapy. Y. enterocolitica is likely to be recognized more frequently as a cause of serious infection in the growing immunosuppressed population. Early recognition and appropriate therapy can improve survival significantly. The Cytotoxic Necrotizing Factors (2007)  from Yersinia pseudotuberculosis and from Escherichia coli Bind to Different Cellular Receptors but Take the Same Route to the Cytosol Eight pathogenic strains (O:1, O:2, O:4, O:13, O:15, O:20, O:21, and O:34) of Y enterocolitica were obtained from the Centers for Disease Control and Prevention (CDC), Atlanta, GA. These specimens were received as freeze-dried organisms, which subsequently were rehydrated with phosphate-buffered saline (PBS) before culture. Yer·sin·ia/ (yer-sin´e-ah) a genus of nonmotile, ovoid or rod-shaped, nonencapsulated, gram- negative bacteria (family Enterobacteriaceae); Y. enterocoli´tica is a ubiquitous species that causes acute gastroenteritis and mesenteric lymphadenitis in children and arthritis, septicemia, and erythema nodosum in adults; Y. pes´tis causes plague in humans and rodents, transmitted from rats to humans by the rat flea, and from person to person by the human body louse; Y. pseudotuberculo´sis causes disease in rodents and mesenteric lymphadenitis in humans. http://medical-dictionary.thefreedictionary.com/YERSINIA Yersinia genus: Y. enterocolitica and Y. pestis. Y. enterocolitica is the most often encountered species of Yersinia in the lab. This bacterium is an invasive pathogen which can penetrate the gut lining and enter the lymphatic system and the blood. Infection, which is usually through ingestion of contaminated foods, can cause a severe intestinal inflammation called yersiniosis. Release of its enterotoxin can cause severe pain similar to that found in patients with appendicitis. Yersinia enterocolitica (1984) Now that its role as a human pathogen is firmly established, reports documenting Yersinia enterocolitica infections are increasing worldwide. The organism has been encountered both sporadically and epidemically (3). Y. enterocolitica causes a diarrheal illness in children (10), and its association with Reiter's syndrome in adults is well known (6, 13), but only a handful of cases of primary soft tissue infection have been described. Y. pestis is included here because it causes the bubonic, pneumonic, and septicemic plagues. Human contraction of bubonic plague is usually through flea bites. Once inside the body, Y. pestis releases a toxin which inhibits electron transport chain function. Swelling of the lymph nodes, skin blotches, and dilerium are sometimes observed within a few days of infection. Untreated infections usually result in death within a week of initial infection. Contributor’s Comment: The mule deer had bilateral ocular infection due to Yersinia pestis. In addition to these changes there were acute necrotizing inflammatory lesions in lung, adrenals, lymph node, and liver with intralesional bacteria, and disseminated intravascular coagulation Plague is unusual in big game animals and ungulates are generally considered resistant to the disease. There is a published report of plague in a free-ranging mule deer in Wyoming,1 an unpublished, laboratory-confirmed case in a mule deer in Montana,2 and bilateral plague- associated necrotizing panophthalmitis in a blacktailed deer in California.3 Ocular plague has been seen in Colorado (Dr. M. Miller, Colorado Division of Wildlife, unpublished observations). Plague is an endemic disease of rodents in the western United States, with occasional spread into human and non-rodent populations via enzootic or amplification hosts.