Food-Borne Infections and
Intoxications:
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Listeria monocytogenes
Campylobacter jejuni
Clostridium botulinum
Clostridium perfringes
Bacillus cereus
Vibrio cholera
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Background and History
3,000,000,000 years ago
3,000,000 years ago
20,000 years ago
10,000 BC
5,000 BC
2,000 BC
900 AD
1202
1850 – 1900
1904
1916
1960
1984
1993
2005
First Bacteria
First Humans
Agricultural societies
Soups, breads, beer
Wine
cooking, drying,
smoking, freezing,
marinating, salting,
and pickling
Yogurt, cheeses
Dietary Laws
Popcorn Chocolate
Sausage Outlawed
Assize of Bread
Handwashing
Pasteuriza tion
Germs discovered
Typhoid Mary
Refrigeration
Hazard Analysis and
Critical Control Point
(HACCP)
Rajneeshees
Jack in the Box E.
coli
Staph and money
Overview of foodborne illness case #'s,
illnesses, hospitalizations and deaths (Table 3)
Listeria monocytogenes
• Gram positive rods
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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
Listeria monocytogenes
• Major public health concern because:
– Severe, non-enteric nature of the disease:
– High case fatality rate  can be as high as 2030%
– Long incubation time
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
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
Listeria monocytogenes
• Habitat and sources
Listeria monocytogenes
• The organism is beta hemolytic and is easily
confused with  hemolytic streptococci. Listeria
may also grow in short chains. Do catalase test!
Listeria monocytogenes
• Growth and Laboratory Characteristics
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Facultative anaerobe
The organism is -hemolytic.
It is catalase positive
It is a gram positive rod
It is psychrotropic
The organism is motile
Listeria monocytogenes
• Clinical signs are similar in all hosts:
– Perinatal listeriosis
– Adult listeriosis
• Both are disseminated infection often with
CNS involvement
Listeria monocytogenes
• Neuromeningeal listeriosis in sheep -- Circling
Disease
Listeria monocytogenes
• Listeriosis in sheep -- pyogranulomatous lesions
Listeria monocytogenes
• Human stillborn -- Granulomaosis infantiseptica
Listeria monocytogenes
• The Disease Entity:
Listeria monocytogenes
• Brain lesions in sheep
Listeria monocytogenes
In addition to professional phagocytes such as
macrophages, these organisms can invade a number
of cell types:
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Epithelial cells
Fibroblasts
Hepatocytes
Endothelial cells
Neurons and possibly other neural cells
Listeria monocytogenes
Internalization:
• Host factors
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E-cadherin,
C-Met
Globular C1-q receptor (complement receptors),
glycosaminoglycans
fibronectin and integrin
• Listeria adhesins:
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Internalin A
Internalin B.
p60
Ami
Lap
fibronectin binding protein (24.6 kDa).
Listeria monocytogenes
• Internalin A (InlA)
– Binds to E-cadherin in the adherens junction, triggering actin cytoskeleton
rearrangements via association with catenins
Listeria monocytogenes
• Internalin A (InlA)
– 800 aa with 14 Nterminal leucine rich
repeats
– Leucine-rich repeat
structure on a
serine/threonine
receptor kinase
– Binds to E-cadherin in
the adherens junction,
Listeria monocytogenes
• Internalin A (InlA)
– 800 aa with 14 Nterminal leucine rich
repeats
– Binds to E-cadherin in
the adherens junction,
triggering actin
cytoskeleton
rearrangements via
association with
catenins
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):
Listeria monocytogenes
• Phagocytic Vacuole
formation
– Phagosome acidifies
– Lysosome fusion
inhibited
Listeria monocytogenes
• Escape from the
Phagocytic Vacuole
– Listeria hemolysin,
(Hly, Listeriolysin,
LLO),
• Cholesterol dependent,
pore forming weak
cytolysin
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
Listeria monocytogenes
Listeria invasion
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Listeria invasion
Gastroenteritis
Gut Associated Lymphatic Tissue
Peyer’s Patch
M Cell
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.
Organism
Reservoirs Human Disease
C. jejuni
Humans,
Diarrhea, systemic illness,
birds, other GBS
mammals
C. coli
Pigs, birds
C. lari
Birds, dogs Diarrhea
C. fetus
Cattle,
sheep
Diarrhea
Systemic illness, diarrhea
Other related organisms include:
C. sputorum, C. concisus, C. curvus, C rectus, C. showae.
Arcobacterium butzleri, A. cryaerophilus, A. skirrowii
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 )
Campylobacter jejuni
Campylobacter jejuni
Reservoirs and epidemiology
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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.
Campylobacter jejuni
Campylobacter jejuni
Pathogenesis and Disease Characteristics
– Low infectious dose
– Two disease entities:
• Diarrhea
• Dysentery
– Associated with Guillaine-Barrè syndrome
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
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
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?
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
Bacillus cereus
• Causes two types of foodborne illness:
• Diarrheal disease
• Emetic disease
Bacillus cereus
Species
B. cereus
B.
anthracis
B.
thuringens
is
B.
mycoides
Colony
morph.
white
Hemolysis Motility
+
+
Crystal
Inclusions
-
white
-
-
-
White or
gray
+
+
+
Rhizoid
(+)
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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
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
Bacillus cereus
Diarrheal vs.Emetic Disease
Characteristic
Diarrheal
Emetic
Infective Dose 105 - 107 cells
105 - 108 per g
Toxin produced: In small
In food
intestine
Toxin type
ProteinCyclic peptide
enterotoxin
Incubation
8-16 hours
30 min-5 hours
period
Duration
1 to several days 6-24 hours
Bacillus cereus
Diarrheal vs.Emetic Disease
Characteristic
Diarrheal
Emetic
Symptoms
Abd pain,
Nausea,
watery diarrhea, vomiting,malais
some nausea
e, diarrhea if
enterotoxin also
produced
Foods
Meat, soups,
Fried rice,
vegetables,
cooked rice,
puddings,
pasta and
sauces, milk
noodles, pastry
Clostridium botulinum
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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
Clostridium botulinum
Clostridium botulinum
Reservoirs
Clostridium botulinum
Food Sources
Clostridium botulinum
• Disease Characteristics:
• Symptoms hit 12-36 hours after ingestion (sometimes sooner,
sometimes weeks later!)
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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
Clostridium botulinum
• Infant Botulism:
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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.
Clostridium botulinum
• Virulence Factors
• Neurotoxin (BoNT)
– water soluble
– produced as a single polypeptide --- 150,000 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:
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A=dimer, trimer, and can be larger
E= monomer and dimer
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B= dimer
A,B,E, F are chromosomally encoded
C, D are phage encoded
G is plasmid encoded
Clostridium botulinumarchitecture of the motor end
plate
Motor neuron
Synaptic cleft
Muscle cell
Clostridium botulinum
Synaptic vessicle
Synaptobrevin
(VAMP):
BoTox B, D, F, G
SNAP-25:
BoTox A, E
Syntaxin
(HPC-1):
BoTox C
Motor end plate of the muscle cell
Synaptic cleft
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
Clostridium perfringes
• Type A
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Symptoms 8-24 hours after ingestion
Resolution 12-24 hours later
Diarrhea and cramps (severe)
No vomiting
No fever
May be serious in the elderly
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, 35000 Da
– heat labile (destroyed by heating 5’ at 60o C)
– Binds to membrane receptor which involves 2 membrane
proteins on the target cell --- 50 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.
Clostridium perfringes
Clostridium perfringes
Vibrio cholera
Whoops !
sorry
Overview of foodborne illness case #'s,
illnesses, hospitalizations and deaths (Tables 1 and 2)
Overview of foodborne illness case #'s,
illnesses, hospitalizations and deaths (Tables 1 and 2)