food-borne infections and intoxications:
DESCRIPTION
Food-Borne Infections and Intoxications:. Listeria monocytogenes Campylobacter jejuni Clostridium botulinum Clostridium perfringes Bacillus cereus Vibrio cholera. Background and History. Overview of foodborne illness case #'s, illnesses, hospitalizations and deaths - (Table 3). - PowerPoint PPT PresentationTRANSCRIPT
Food-Borne Infections and Intoxications:
• 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 First Bacteria
3,000,000 years ago First Humans
20,000 years ago Agricultural societies
10,000 BC Soups, breads, beerWinecooking, drying,smoking, freezing,marinating, salting,and pickling
5,000 BC Yogurt, cheesesDietary Laws
2,000 BC Popcorn Chocolate
900 AD Sausage Outlawed 1202 Assize of Bread 1850 – 1900 Handwashing
PasteurizationGerms discovered
1904 Typhoid Mary 1916 Refrigeration 1960 Hazard Analysis and
Critical Control Point(HACCP)
1984 Rajneeshees1993 Jack in the Box E.
coli 2005 Staph and money
Overview of foodborne illness case #'s, illnesses, hospitalizations and deaths -
(Table 3)
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
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
Listeria monocytogenesRisk 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– 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:
• Epithelial cells
• Fibroblasts
• Hepatocytes
• Endothelial cells
• Neurons and possibly other neural cells
Listeria monocytogenesInternalization:
• 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).
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 N-
terminal 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 N-
terminal 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
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, birds, other mammals
Diarrhea, systemic illness, GBS
C. coli Pigs, birds Diarrhea
C. lari Birds, dogs Diarrhea
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
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
• 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 cereusSpecies Colony
morph.Hemolysis Motility Crystal
Inclusions
B. cereus white + + -
B. anthracis
white - - -
B. thuringensis
White or gray
+ + +
B. mycoides
Rhizoid (+) - -
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 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
Bacillus cereusDiarrheal 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
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
Clostridium botulinum
Clostridium botulinumReservoirs
Clostridium botulinumFood Sources
Clostridium botulinum
• Disease Characteristics:
• Symptoms hit 12-36 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
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.
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:
• 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
Clostridium botulinum- architecture of the motor end
plate
Synaptic cleft
Muscle cell
Motor neuron
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
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
• 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)