NHIỄM TRÙNG NHIỄM ĐỘC TỪ THỰC PHẨM

1. NHIỄM TRÙNG NHIỄM ĐỘC TỪ THỰC PHẨM GS TS BS LÊ HOÀNG NINH

2. Food-Borne Infections and Intoxications: • Listeria monocytogenes • Campylobacter jejuni • Clostridium botulinum • Clostridium perfringes • Bacillus cereus • Vibrio cholera

3. Background and History

4. Overview of foodborne illness case #'s, illnesses, hospitalizations and deaths - (Table 3)

5. Listeria monocytogenes • Gram positive rods • Faculative anaerobe • No spores • No capsule • Motile 10-25o C • Closely related to Bacillus, Clostridium, Enterococcus, Streptococcus and Staphylococcus • Genus has 6 species-- L. monocytogenes and L. ivanovii are pathogenic

6. Listeria monocytogenes • Major public health concern because: • Severe, non-enteric nature of the disease: • High case fatality rate  can be as high as 20-30% • Long incubation time

7. Listeria monocytogenes • Risk groups • Pregnant women and neonates • Elderly • Immunocompromised or debilitated people: • Malignancy, antineoplastic treatment, immunosuppressed, chronic liver disease, collagen diseases (lupus), diabetes, AIDS

8. Listeria monocytogenes • Properties of the Organism: • Habitat and sources -- widely distributed! - (next slide) • Bottom line  Many foods have been implicated but foods marketed as refrigerated and ready to eat are the ones that have been associated with most of the outbreaks. • Human Carriage

9. Listeria monocytogenes • Habitat and sources

10. Listeria monocytogenes • The organism is beta hemolytic and is easily confused with  hemolytic streptococci. Listeria may also grow in short chains. Do catalase test!

11. Listeria monocytogenes • Growth and Laboratory Characteristics • Facultative anaerobe • The organism is -hemolytic. • It is catalase positive • It is a gram positive rod • It is psychrotropic • The organism is motile

12. Listeria monocytogenes • Clinical signs are similar in all hosts: • Perinatal listeriosis • Adult listeriosis • Both are disseminated infection often with CNS involvement

13. Listeria monocytogenes • Neuromeningeal listeriosis in sheep -- Circling Disease

14. Listeria monocytogenes • Listeriosis in sheep -- pyogranulomatous lesions

15. Listeria monocytogenes • Human stillborn -- Granulomaosis infantiseptica

16. Listeria monocytogenes • The Disease Entity:

17. Listeria monocytogenes • Brain lesions in sheep

19. Listeria monocytogenes In addition to professional phagocytes such as macrophages, these organisms can invade a number of cell types: • Epithelial cells • Fibroblasts • Hepatocytes • Endothelial cells • Neurons and possibly other neural cells

20. Listeria monocytogenes Internalization: • Host factors • E-cadherin, • C-Met • Globular C1-q receptor (complement receptors), • glycosaminoglycans • fibronectin and integrin • Listeria adhesins: • Internalin A • Internalin B. • p60 • Ami • Lap • fibronectin binding protein (24.6 kDa).

21. Listeria monocytogenes • Internalin A (InlA) • Binds to E-cadherin in the adherens junction, triggering actin cytoskeleton rearrangements via association with catenins

22. Listeria monocytogenes • Internalin A (InlA) • 800 aa with 14 N-terminal leucine rich repeats • Leucine-rich repeat structure on a serine/threonine receptor kinase • Binds to E-cadherin in the adherens junction,

23. Listeria monocytogenes • Internalin A (InlA) • 800 aa with 14 N-terminal leucine rich repeats • Binds to E-cadherin in the adherens junction, triggering actin cytoskeleton rearrangements via association with catenins

24. Listeria monocytogenes • Vacuole formation, proliferation and spread: • phagosome formation, lysis and release • Listeria hemolysin Hly (also known as listeriolysin or LLO) • Listeria phospholipases: PlcA and PlcB (phospholipase C A and B):

25. Listeria monocytogenes • Phagocytic Vacuole formation • Phagosome acidifies • Lysosome fusion inhibited

26. Listeria monocytogenes • Escape from the Phagocytic Vacuole • Listeria hemolysin, (Hly, Listeriolysin, LLO), • Cholesterol dependent, pore forming weak cytolysin

27. Listeria monocytogenes • Escape from the Phagocytic Vacuole • Listeria phospholipases: PlcA and PlcB (phospholipase C A and B) • Role in escape from the phagosome • Escape from the double membrane vessicle in cell to cell spread • Subvert host cell signalling pathways

28. Listeria monocytogenes

29. Listeria invasion

30. Listeria invasion

31. Gastroenteritis

32. Gut Associated Lymphatic Tissue

33. Peyer’s Patch

34. M Cell

35. Campylobacter jejuni • Campylobacter jejuni is the leading cause of gastroenteritis in the US and probably world-wide. . • Hawai'i has the highest incidence in the country  about 900 reported cases a year with an incidence of 75/100,000, but the thinking is that infections are grossly underreported.

37. Campylobacter jejuni Properties of the organism • Curved s-shaped gram (-) rods, motile with a single polar flagellum at one or both ends. • Defined "viable but not culturable" state. • respiratory metabolism, microaerophilic. • Grow with 10% CO2 / 5% O2 . Some species / strains require additional H2 in the atmosphere • C. jejuni will grow at 42o C and this is used as a selection criterion. • The organism is unusually thin (0.2 - 0.9 )

38. Campylobacter jejuni

39. Campylobacter jejuni Reservoirs and epidemiology • Human cases are associated with: • Poultry - especially eating chicken out • Pets - especially young puppies • Water supply • Raw milk • Most cases occur in the summer months -- late spring to early autumn -- this is also true in Hawai'i.

40. Campylobacter jejuni

41. Campylobacter jejuni • Pathogenesis and Disease Characteristics • Low infectious dose • Two disease entities: • Diarrhea • Dysentery • Associated with Guillaine-Barrè syndrome

42. Campylobacter jejuni • Virulence factors • Cj can invade intestinal epithelial cells. • Cj secretes a number of novel proteins upon cultivation with enterocytes: • CiaB • pVir, present only in some strains of Cj appears to be important for invasion. • Microtubule mediated endocytosis occurs • Cj apparently stays within vacuole • adenyl cyclase activating cholera toxin-like enterotoxin • cytotoxin

43. Campylobacter jejuni • Virulence factors • Microtubule mediated endocytosis occurs and microfilament mechanism may be involved too • Microtubules aggregate into finger-like protrusions with C.j. at the tips

44. Campylobacter jejuni • Virulence factors • Cytolethal Distending Toxin • Irreversable cell cycle arrest • All three CDT genes need to be expressed for activity • Adenyl cyclase activating enterotoxin?

45. Campylobacter jejuni • Guillaine-Barrè Syndrome • Ascending muscle weakness or paralysis, rapidly progressing • 40% of GBS patients have evidence of Campylobacter infection • Penner 1,2,8,17,19,41 are disproportionately represented • LPS oligosaccharides structurally related to human motor neuron gangliosides

46. Bacillus cereus • Causes two types of foodborne illness: • Diarrheal disease • Emetic disease

47. Bacillus cereus

48. Bacillus cereus • Gram positive large (width > 1 um) rod, • spore former -- central spore or paracentral • grows aerobically and anaerobically • beta hemolytic • usually motile • may be present in stools of healthy individuals • grown out of food samples after heat shock --> treat sample at 70o C for 10 minutes; or after ethanol shock --> mix 1:1 with absolute ethanol for 1 hour • Widely disseminated in nature • Rice, spices and dairy products

49. Bacillus cereus • Disease entities: • Two types of food borne illness: • Emetic --- emetic toxin, food intoxication • circular peptide, 1.2 kDa, called cereulide • Stimulates the vagus nerve leading to the emetic response. • Diarrheal --- enterotoxin, food infection • At least three enterotoxins have been described

50. Bacillus cereus