YERSINIOSIS, STREPTOCOCCUS SUIS, GLANDERS.pptx

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1. YERSINIOSIS, STREPTOCOCCUS SUIS, GLANDERS By Akshat sharma 57

2. Yersiniosis Members of the family Enterobacteriaceae They are gram-negative bacilli Causative agents Yersinia enterocolitica bacteria Yersinia pseudotuberculosis

3. Causative agents Y. enterocolitica or Y. pseudotuberculosis. Flagella stained specimen, reveals the presence of a few, rod shaped, flagellated, Yersinia enterocolitica bacteria Gram stained specimen, reveals a field of numerous Gram-negative, rod shaped, Yersinia enterocolitica bacteria

4. Pigs and other wild and domestic animals are the usual hosts. Human infection occurs due to consumption of contaminated food such as raw pork, milk, etc. Yersiniosis is most common in childhood and in colder climates Patients present with abdominal pain and sometimes with diarrhea. Y. enterocolitica is found worldwide, most commonly in Northern Europe and America Outbreaks of Y. pseudotuberculosis are generally rare, have been reported from Finland.

5. Serogrouping Y. enterocolitica is further characterized biochemically (six biotypes) and antigenically (60 serotypes, based on somatic O antigen). Worldwide, most clinical infections are associated with serogroups 0:3 and 0:9 Y. pseudotuberculosis can be further differentiated into six serotypes (1 to 6) based on somatic O and flagellar H antigens.

6. Virulence Factors Virulence factors common to both the species: Inv protein (invasin) - It binds to beta-1 integrins on M cells of GI mucosa which helps in invasion Ail protein - It helps in attachment, invasion and inactivates complement Yersinia adhesin A (Yad A)- 1, Binds to extra cellular protein matrix proteins, such as collagen and fibronectin and help in invasion 2, Inactivates complements.

7. Y. enterocolitica specific virulence factors: Myf antigen is a fimbrial antigen, helps in adhesion Heat-stable toxin : Similar to that of E. coli, produced only at temperature <30°C PH6 antigen : Fimbrial surface protein, helps in adhesion. It is also expressed by Y. pestis. Y. pseudotuberculosis specific virulence factors: Super antigen-binds to T cells non-specifically leading to massive cytokine release.

8. Clinical manifestations Self limiting gastroenteritis Terminal ileitis Septicemia Post-infective phenomena (in adults) occurs commonly with Y. enterocolitica. It occurs as a result of autoimmune activity, initiated by the deposition of bacterial non-viable components in joints and other sites. - Reactive atheritis, Graves’ disease etc.. Super antigen

9. Lab diagnosis For isolation from blood: Blood culture bottles (BHI broth) should be used For isolation from lymph nodes aspirate: Culture is done on conventional media (blood agar, nutrient agar and MacConkey agar) • Blood agar: They produce granular translucent colonies with a beaten copper surface, non-hemolytic colonies • MacConkey agar: Growth of Y. pseudotuberculosis is poor. Y. enterocolitica grows well and produces lactose non-fermenting pale colonies. BHI broth

10. CIN AGAR (DARK RED BULL’S EYES) Blood agar (Non Hemolytic colonies) Y. Enterocolitica (MacConkey agar)

11. Cont… For isolation from feces, food or soil: Selective media should be used, such as: Deoxycholate citrate agar, MacConkey agar Yersinia CIN agar (Cefsulodin-irgasan-novobiocin): Typical dark red bull’s eye appearing colonies are formed in 24 hours Biochemical Tests Y. Enterocolitica and Y. pseudotuberculosis show the following properties by which they can be differentiated from Y. pestis: Differential motility: They are motile at 22°C (but not at 37°C) - Cold enrichment: Growth improves on refrigeration (4°C) - Urease positive

12. Serology Antibodies can be detected by agglutination or ELISA using serotype specific O-antigen types. In Y. pseudotuberculosis infection, antibodies appear early during acute phase of illness; whereas Y. enterocolitica specific agglutinating antibodies are more likely to be found in convalescent sera.

13. Streptococcus suis S. suis was first identified as an etiological factor of human infections in 1968 Meningitis, sepsis, or arthritis, etc Main risk groups for S. suis infection are subjects being occupationally exposed to pigs and/or pork, for example, farmers, butchers, meat sellers, foresters, and hunters

14. Overview S. suis have been reported to have spread over 30 countries and/or regions and has claimed no less than 1600 human cases, some of which were fatal S. Suis is classified into 35 serotypes based on the differentiation of capsule antigens. Generally, serotype 2 of S. suis (SS2) is considered to be the most virulent, and is frequently isolated from clinically-diseased piglets. SS2 seems to be a previously neglected but recently emerging human pathogen, 5 whose infection has become increasingly potent, especially in the southeast Asian countries like Thailand, 6 Vietnam, 7 and China. 8 , 9

15. S. Suis Heterogeneous Gram-positive Facultative anaerobe, spherical or ovoid in shape, typically presents in pairs or as short chains Presence of alpha hemolysis on selective media enriched with horse blood Hosts: pig, horse, dog, cat, human

16. Lab diagnosis More accurate identification requires additional biochemical tests: Arginine dihydrolase (positive result) Production of acid from lactose, sucrose, and inulin (positive result) Synthesis of acid from glycerol, mannitol, and sorbitol (negative result) Gram-positive cocci

17. Clinical presentation Meningitis Similar presentation to other purulent meningitis However contrary to purulent meningitis of other etiologies, infections caused by S. suis show a tendency to relapse Prolonged, biphasic course with frequent incidence of cerebellar ataxia and deafness Exacerbation of the symptoms is usually observed after 2-3 weeks of first line antibiotic therapy

18. Glanders Burkholderia mallei –Gram negative bacillus –Exists primarily in infected host –Prolonged survival in favorable environments –Inactivated by heat and sunlight

19. Hosts and people at risk Hosts- Donkey, horses Carnivores, humans, and goats susceptible People at risk- Veterinarians Grooms Horsemen Butchers Lab workers

20. History World War I –Suspected use as biological agent to infect Russian                               horses and mules –Large number of human cases in Russia during                      and after WWI World War II –Japanese infected horses, civilians, and POWs –U.S. and Russia investigated use as biological weapon

21. Transmission: Humans Direct contact with infected animals Abraded skin Mucous membranes Fomites (infected items) Inhalation Ingestion Person-to-person (rare)

22. Disease in Humans Four forms of infection Localized cutaneous Pulmonary Septicemic Chronic form Generalized symptoms- –Fever, malaise, muscle ache, chest pain   •Case-fatality rate: 95% (untreated)

23. “Farcy” (cutaneous form) –Multiple abscesses •Muscles, joints, spleen, liver −Weight loss −Lymphadenopathy •Case-fatality rate: 50% (treated) •Relapses common •Disease can last up to 25 years

24. Lab diagnosis Culture and Gram stain –Sputum, urine, skin lesions, blood –Gram negative bacilli –Safety pin appearance Agglutination tests –May be positive after 7 to 10 days –High background titer in normal sera makes interpretation difficult  

25. Cont… Complement fixation   –More specific –Positive if titer is equal to or greater than 1:20 Chest radiograph for the pulmonary form of disease PCR