1. 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.

36. Organism
Reservoirs
Human Disease
C. jejuni
Humans, birds, other mammals
Diarrhea, systemic illness, GBS
C. coli
Pigs, birds
Diarrhea
C. lari
Birds, dogs
C. fetus
Cattle, sheep
Systemic illness, diarrhea
Other related organisms include:
C. sputorum, C. concisus, C. curvus, C rectus, C. showae. Arcobacterium butzleri, A. cryaerophilus, A. skirrowii

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 ( )

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 cytotoxin
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 Species Colony morph. Hemolysis Motility
Crystal Inclusions
B. cereus
white + -
B. anthracis
B. thuringensis
White or gray
B. mycoides
Rhizoid
(+)

48. Bacillus cereus Rice, spices and dairy products
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. Diarrheal vs.Emetic Disease
Bacillus cereus
Diarrheal vs.Emetic Disease
Characteristic
Diarrheal
Emetic
Infective Dose
cells
per g
Toxin produced:
In small intestine
In food
Toxin type
Protein-enterotoxin
Cyclic peptide
Incubation period
8-16 hours
30 min-5 hours
Duration
1 to several days
6-24 hours

51. Diarrheal vs.Emetic Disease
Bacillus cereus
Diarrheal vs.Emetic Disease
Characteristic
Diarrheal
Emetic
Symptoms
Abd pain, watery diarrhea, some nausea
Nausea, vomiting,malaise, diarrhea if enterotoxin also produced
Foods
Meat, soups, vegetables, puddings, sauces, milk
Fried rice, cooked rice, pasta and noodles, pastry

52. Clostridium botulinum
Gram positive rod
anaerobic
spore former
seven types based on serologic specificity of neurotoxin named A through G
A, B, E and sometimes F --> causes of human botulism
C and D ---> animal botulism, contaminated feed.
G ---> no clear association with disease

53. Clostridium botulinum

54. Clostridium botulinum
Reservoirs

55. Clostridium botulinum
Food Sources

56. Clostridium botulinum
Disease Characteristics:
Symptoms hit hours after ingestion (sometimes sooner, sometimes weeks later!)
nausea and vomiting (B and E)
visual impairment: blurred, ptosis, dilated pupils
loss of mouth and throat function (A and B)
dry mouth, throat, tongue, sore throat
fatigue and loss of coordination
respiratory impairment
abdominal pain and either diarrhea or constipation

57. Clostridium botulinum
Infant Botulism:
constipation --- days to week after onset
generalized weakness and a weak cry
poor feeding and sucking reflex
lack of facial expression
floppiness
respiratory arrest may occur although death is rare.

58. Clostridium botulinum
Virulence Factors
Neurotoxin (BoNT)
water soluble
produced as a single polypeptide ,000 MW (progenitor)
cleaved by a protease to form two polypeptides which then become S-S bonded : 100,000 and 50,000 MW
There are differences in serotypes:
A=dimer, trimer, and can be larger
E= monomer and dimer
B= dimer
A,B,E, F are chromosomally encoded
C, D are phage encoded
G is plasmid encoded

59. Clostridium botulinum- architecture of the motor end plate
Synaptic cleft
Muscle cell
Motor neuron

60. Clostridium botulinum
Synaptic vessicle
Synaptobrevin (VAMP):
BoTox B, D, F, G
Synaptic cleft
SNAP-25:
BoTox A, E
Syntaxin (HPC-1):
BoTox C
Motor end plate of the muscle cell

61. Clostridium perfringes
Type A food poisoning
Necrotizing enteritis (Enteritis necroticans) also known as Darmbrand or Pigbel - caused by Type C
Gram positive rod
Spore forming
anaerobic but tolerant of some exposure to air
under optimal conditions, is capable of doubling every 10 minutes
ubiquitous distribution --- feces and soil

62. Clostridium perfringes
Type A
Symptoms 8-24 hours after ingestion
Resolution hours later
Diarrhea and cramps (severe)
No vomiting
No fever
May be serious in the elderly

63. Clostridium perfringes
Infection --- organisms multiply and then sporulate in the small intestine.
CPE (Clostridium perfringes enterotoxin) is released during the sporulation process.
CPE is a single polypeptide, Da
heat labile (destroyed by heating 5’ at 60o C)
Binds to membrane receptor which involves 2 membrane proteins on the target cell and 70 kDa -- (Fig 7 and 8).
Inserts into the membrane and is believed to cause a membrane lesion which then alters permeability -- fluid and electrolyte loss and damage to the epithelium. Glucose is still absorbed.

64. Clostridium perfringes

65. Clostridium perfringes

66. Vibrio cholera
Whoops !
sorry

67. Overview of foodborne illness case #'s, illnesses, hospitalizations and deaths - (Tables 1 and 2)

68. Overview of foodborne illness case #'s, illnesses, hospitalizations and deaths - (Tables 1 and 2)