Yersinia pseudotuberculosis (Y. pseudotuberculosis) is a gram- negative facultative anaerobe bacillus that can grow at low temperature (4°C). Consequently, the quantity of bacteria in food after several days of conservation in a refrigerator increases dramatically. It belongs, together with its homologue Yersinia pestis, to the family of Enterobacteriaceae. Yersinia pseudotuberculosis strains can be divided into 5 different serotypes. Yersiniosis has a wide range of clinical manifestations. The commonest is a self limiting gastroenteritis , but more serious variants may occur, such as appendicitis like syndrome  or crohn like disease . We describe a small bowel necrosis associated with Y. pseudotuberculosis infection.
2. Case report
A 50 years old man was admitted to the emergency room with a seven day history of diffuse abdominal pain, fever, 4 time per day bloody diarrhea and weight loss. He received oral amoxicillin clavulanate two gram a day during four days without improvement. On physical examination, he had a temperature of 39 °C and a generalized abdominal tenderness to deep palpation, especially on the lower right quadrant. Laboratory work-up yielded the following: ; white blood cell count, 14.6×109 L-1; C-reactive protein,150 mg L-1 (normal <5); Renal Function, electrolytes, amylasemia, Blood and urine cultures were normal. Plain abdominal roentgenogram showed small bowel gas localized in the lower right quadrant. Abdominal ultrasound and CT scan showed thickening of an ileal loop and the mesenteric wall associated with intraabdominal effusion (figure 1). On the third day of admission, severe abdominal pain developed, the abdomen was protuberant, and bowel sounds were absent. Emergency exploratory laparotomy was performed. Seropurulent effusion and necrosis involving 30 cm of the distal part of the small bowel, at about 24 centimeters from the ileocecal valve was found. The mesentery appeared thickened and there was also found an extended thrombosis of all mesentery veins, draining the area of bowel necrosis. Resection of the necrotic small bowel was performed (figure 2) and histology showed extensive hemorrhagic necrosis affecting all the layers of the ileum and transmural inflammation of the ileum and the venous walls with neutrophils. Histological findings were not consistent with Crohn disease and no pathogenic organisms were cultured from the specimen. However, as suggested by histological findings, Y. pseudotuberculosis serology was performed and found positive with an antibody titre of 1/440, consistent with recent Y. pseudotuberculosis infection. Blood coagulation tests were normal. Tuberculin skin test and a Ziehl-Neelsen stain of the sputum for acid-fast bacilli, and serology for brucellosis and salmonellosis were negative. Antibiotic therapy with ciprofloxacin was started. On the twenth day post surgery the patient was discharged, in good clinical conditions.
The distribution of Y pseudotuberculosis infection is worldwide but it could be most commonly found in countries with cold and temperate climate. It is a bacterium isolable from the earth, from water, from a variety of foodstuffs and from human beings and animals. The animal reservoirs include many mammalian and avian hosts, such as dogs, cats, horses, cattle, rabbits, deer, rodents, and birds. An example of occupational exposure to Y pseudotuberculosis related to animal reservoirs involves butchers working in abattoirs slaughtering swine. Y pseudotuberculosis infections in humans are primarily acquired through the gastrointestinal tract after consumption of contaminated food products. Transmission may occur zoonotically, interpersonal or through consumptions of foodstuffs (in particular raw or undercooked pork products), unpasteurized milk or water not treated with chlorine. The most common manifestations of Y. pseudotuberculosis infection in humans are mesenteric lymphadenitis and ileocolitis accompanied by abdominal pain and fever. Y. pseudotuberculosis causes mesenteric lymphadenitis and may affect the appendix tissue and mimic appendicitis. Inflammation may affect the ileum and sometimes spread to the caecum simulating macroscopically Crohn’s disease in its acute phase [4,5]. A mass formation, related to Y.P. infection, could occur in the right upper quadrant of the abdomen, which could be confused with tumoral lesions. Local complications due to Y. pseudotuberculosis have been reported rarely, such as severe bleeding, colonic perforation, subacute obstruction, and intussusceptions [6-8]. This is only one similar case of bowel necrosis following mesenteric veins thrombosis, due to Y. enterocolitica infection . Colonic perforation and intussusception were reported in children and subacute obstruction and severe bleeding were reported in adults. We have already published a case report describing a small bowel necrosis related to Y. pseudotuberculosis infection . Other manifestations of infection may include erythema nodosum, arthralgias, reactive arthritis, and ankylosing spondylitis. Y pseudotuberculosis infection has also been documented to cause lumbar facet joint disease. Acute renal failure has been reported, although very rarely. Far East scarlatinoid fever was first described in the context of Y pseudotuberculosis infection. A scarlatinoid-appearing rash involving the head and neck, upper and lower extremity erythema, mucous membrane enanthem, strawberry tongue and features shared with Kawasaki disease (eg, coronary artery aneurysms) characterize this syndrome. Y pseudotuberculosis is a gram-negative, non–lactose-fermenting coccobacillus that is chemically differentiated from other species by its fermentation of sorbitol and ornithine decarboxylase activity, among other features. The optimum growth of yersinia occurs on MacConkey medium at 20-35°C. The organism is urease-positive. Our case was negative for cultures in blood and stools, probably because of the previous antibiotic therapy. Isolation of organism from stool is difficult given the slow growth pattern and overgrowth of normal fecal flora . However, stool culture yield may be increased with cold enrichment, special culture media, or alkali treatment, but these methods are generally not cost-effective . Blood, peritoneal fluid, pharyngeal exudate, and synovial fluid may yield the organism. Enzyme-linked immunosorbent assay (ELISA) and agglutination tests may be obtained; the antibodies (against the O antigen) may appear soon after the onset of illness and typically wane over 2-6 months. However, cross-reaction between antibodies against other organisms may obscure the diagnostic picture. These other organisms include other Yersinia, Vibrio, Salmonella, Brucella, and Rickettsia species. Polymerase chain reaction (PCR) methods are sensitive, efficient, and accurate tools for identifying and serotyping Y pseudotuberculosis . Y pseudotuberculosis infection is often self-limited. However, more toxic presentations, including septic syndromes, severe dehydration, or chronic presentation, may warrant antibiotic therapy. Yersinia enterocolitica is susceptible to different antibiotics (amino-glycosides, tetracyclines, trimethoprin-sulfamethoxazole, ciprofloxacin) while it is in general resistant to penicillin, to ampicillin and to first-generation cephalosporin.
Yersinia may be a more important cause of acute abdominal conditions than is currently appreciated, and If specific antibody tests would have been performed routinely in every case of acute intestinal problems, the positive diagnosis of Y pseudotuberculosis could have been made much more commonly.