Pseudotuberculosis

a detailed explanation of pseudotuberculosis

1. Pseudotuberculosis -Ladi Anudeep ISM-IUK

2. Introduction The genus Yersinia includes 18 species, three of which are important human pathogens: Yersinia pestis, Yersinia enterocolitica, and Yersinia pseudotuberculosis Y. enterocolitica and Y. pseudotuberculosis cause yersiniosis, a diarrheal illness. The yersinioses are zoonotic infections of domestic and wild animals; humans are considered incidental hosts that do not contribute to the natural disease cycle.

3. Microbiology Y.tuberculosis is a gram negative, lactose-negative, oxidase-negative, and urease-positive that causes illness similar to scarlet fever Humans occasionally get infected zoonotically most often food borne route Structure consists of 2 antigens: Somatic-O antigen and flagellar-H antigen Y. pseudotuberculosis has been isolated from a variety of mammals, rodents and birds. Human is not a source of infection Yersinia pseudotuberculosis  survives intracellularly

4. Transmission Transmission of yersiniosis is largely foodborne and occasionally waterborne There are also reports of infection related to exposure to household pets and transfusion of blood products Data on the transmission of Y. pseudotuberculosis are limited. Outbreaks have been associated with consumption of contaminated lettuce, carrots, and milk Risk factors associated with yersiniosis include consumption of undercooked or raw pork products, exposure to untreated water, blood transfusion, derangements of iron metabolism (such as cirrhosis, hemochromatosis, aplastic anemia, thalassemia, and iron overload), and other comorbid conditions (such as malignancy, diabetes, malnutrition, and gastrointestinal illness).

5. Incidence of disease Sporadic yersiniosis has been observed worldwide. The incidence of disease around the world increased substantially in the 1970s It was reported frequently in northern Europe, particularly in Belgium, Norway, and the Netherlands; it is rarely observed in tropical countries The incidence of Yersinia infections is highest in young children

6. Pathogenesis Organisms are ingested in contaminated foods, such as salads containing carrots or lettuce, or as pork, or in water Incubation period: 8 days(avg) bacteria reach the terminal ileum and proximal colon, where they penetrate through epithelial cells overlying gut-associated lymphoid tissues including Peyer’s patches. As an intracellular infection, bacteria are taken up by macrophages, where they survive and proliferate. Y. pseudotuberculosis  acts to inhibit phagocytosis, allowing organisms more access to mesenteric lymph nodes and the blood stream

7. Results of this infection are mucosal ulcerations in the terminal ileum, less commonly ulcerations in the ascending colon, necrotic lesions in Peyer’s patches, and enlargement of mesenteric lymph nodes.  Then gains access to blood stream and spreads to visceral organs i.e., liver and spleen

8. Clinical Features Includes intoxication syndrome, exanthemas infected GIT syndrome The most common clinical  Y pseudotuberculosis  syndromes are self-limited enterocolitis and mesenteric lymphadenitis ( pseudoappendicitis ) The most common presentation is fever and abdominal pain or cramps About half the patients have back pain and a quarter of patients have vomiting or diarrhea.  The abdominal pain is often in the right lower quadrant corresponding to a clinical picture of distal ileitis and regional lymphadenitis that gives rise to the diagnostic appellation of “ pseudoappendicitis . skin rash, strawberry tongue, hypotension, and lymphadenopathy are also seen

9. The infection can spread from the abdomen by way of the blood stream, especially in immunocompromised persons, to cause septicemia, liver or splenic abscesses, osteomyelitis, and septic arthritis General intoxication symptoms like weakness, headache, arthralgias, myalgias, anorexia, vomiting GIT syndrome: abdominal pain, diarrhea Y pseudotuberculosis  is associated with postinfectious complications such as erythema nodosum, reactive arthritis, iritis, and glomerulonephritis.  Erythema nodosum on the lower limbs is the exanthem found in pseudotuberculosis

10. Diagnosis Y. pseudotuberculosis  can be identified in cultures Stool culture is the preferred clinical specimen for patients with intestinal symptoms Can also be detected by its features of being a Gram-negative bacillus that is lactose-negative, oxidase-negative, and urease-positive General blood analysis shows leukocytosis, neutrophilia

11. Treatment Treatment is not warranted in most cases of self-limited mesenteric lymphadenitis and ileitis Etiological treatment Antimicrobial treatment is preferred Resistance to penicillin, ampicillin, 1 st gen cephalosporins is reported Susceptible to other beta-lactam agents, aminoglycosides, tetracyclines, chloramphenicol, trimethoprim-sulfamethoxazole, and fluoroquinolones

12. Ciprofloxacin: 30mg/kg/day in 2 doses Ceftriaxone: 100mg/kg/day 1-2 times Cephazolin: mg/kg/day in 2 doses Streptomycin: 5mg/kg/day in 2 doses Trimethoprim(8mg/kg/day)-sulfamethoxazole(40mg/kg/day) in 2 doses