1. 507 Bacterial Pathogenesis
Botulism
507 Bacterial Pathogenesis

2. History Disease – botulism Agent – botulinum toxin
Source of toxin - Clostridium botulinum
Discovered in 1895
WuDunn S, Miller J, Broad WJ.
How Japan germ terror alerted world.
New York Times.
May 26, 1998:A1, A10.
Tucker JB, ed.
Toxic Terror: Assessing the Terrorist Use of Chemical and Biological
Weapons.
Cambridge, Mass: MIT Press; 2000.

3. Epidemiology All ages and genders equally susceptible Mortality
25% prior to 1960
6% during 1990’s

4. Epidemiology Incubation period Depends on inoculated dose Inhalational
12-18 hours in primate studies
72 hours in 3 known inhalational cases
True incubation period is unknown
Foodborne
6 hours to 8 days
Wound
7.5 days (range 4-18 days) after injury
Schantz EJ, Johnson EA.
Properties and use of botulinum toxin and other microbial neurotoxins
in medicine.
Microbiol Rev.
1992;56:80-99.
Franz DR, Pitt LM, Clayton MA, Hanes MA, Rose KJ.
Efficacy of prophylactic and therapeutic administration of antitoxin for
inhalation botulism.
In: DasGupta BR, ed. Botulinum and Tetanus Neurotoxins:
Neurotransmission and Biomedical Aspects. New York, NY: Plenum
Press; 1993:
Herrero BA, Ecklung AE, Streett CS, Ford DF, King JK.
Experimental botulism in monkeys: a clinical pathological study.
Exp Mol Pathol.
1967;6:84-95.
Scott AB, Suzuki D.
Systemic toxicity of botulinum toxin by intramuscular injection in the
monkey.
Mov Disord.
1988;3:

5. Microbiology C. Botulinum Gram-positive obligate anaerobic bacillus
Spore-forming
Produces botulinum toxin
Heat sensitive as bacillus
Prefers low acid environment
Inglesby, T. The Washington Post
Wednesday, December 9, 1998; Page H01

6. Microbiology C. Botulinum spores Ubiquitous Soil Airborne dust
Surfaces of raw fruits and vegetables
Seafood
WuDunn S, Miller J, Broad WJ.
How Japan germ terror alerted world.
New York Times.
May 26, 1998:A1, A10.
Tucker JB, ed.
Toxic Terror: Assessing the Terrorist Use of Chemical and Biological
Weapons.
Cambridge, Mass: MIT Press; 2000.

7. Microbiology Botulinum toxins Consist of light and heavy chains
Light chain – zinc endopeptidase
The bioactive component
Environmental survival
Inactivated by heat > 85ºC for 5 min
pH <4.5

8. Microbiology Toxin Classification All have same clinical effect
Types A-G, antigenically distinct
Type A- 54%, Type B- 15%, Type E- 27%
Type A- Western U.S., Type B- Eastern
Types C, D reported in animals only
Type G in soil samples only
Humans likely susceptible to all types

9. Pathogenesis Possible routes of exposure
Inhalation of toxin (in a biological attack)
Food or water toxin contamination
Wound infected with C. Botulinum
Ingestion of C. botulinum

10. Pathogenesis crystalline type A toxin 0.09-0.15 g given iv or im
Estimated lethal human dose
crystalline type A toxin
g given iv or im
g inhalationally
70 g given po
Schantz EJ, Johnson EA.
Properties and use of botulinum toxin and other microbial neurotoxins
in medicine.
Microbiol Rev.
1992;56:80-99.
Franz DR, Pitt LM, Clayton MA, Hanes MA, Rose KJ.
Efficacy of prophylactic and therapeutic administration of antitoxin for
inhalation botulism.
In: DasGupta BR, ed. Botulinum and Tetanus Neurotoxins:
Neurotransmission and Biomedical Aspects. New York, NY: Plenum
Press; 1993:
Herrero BA, Ecklung AE, Streett CS, Ford DF, King JK.
Experimental botulism in monkeys: a clinical pathological study.
Exp Mol Pathol.
1967;6:84-95.
Scott AB, Suzuki D.
Systemic toxicity of botulinum toxin by intramuscular injection in the
monkey.
Mov Disord.
1988;3:

11. Pathogenesis Toxin must enter body Does not penetrate intact skin
Direct toxin absorption from mucosal surface
Gut – foodborne
Lungs – inhalational
Via toxin produced by infection with C.botulinum
Skin breaks – wound botulism after trauma, IV drugs
Gut – intestinal botulism
Would not be seen in BT event, as toxin would be used
Does not penetrate intact skin
Schantz EJ, Johnson EA.
Properties and use of botulinum toxin and other microbial neurotoxins
in medicine.
Microbiol Rev.
1992;56:80-99.
Franz DR, Pitt LM, Clayton MA, Hanes MA, Rose KJ.
Efficacy of prophylactic and therapeutic administration of antitoxin for
inhalation botulism.
In: DasGupta BR, ed. Botulinum and Tetanus Neurotoxins:
Neurotransmission and Biomedical Aspects. New York, NY: Plenum
Press; 1993:
Herrero BA, Ecklung AE, Streett CS, Ford DF, King JK.
Experimental botulism in monkeys: a clinical pathological study.
Exp Mol Pathol.
1967;6:84-95.
Scott AB, Suzuki D.
Systemic toxicity of botulinum toxin by intramuscular injection in the
monkey.
Mov Disord.
1988;3:

12. Pathogenesis Wound Botulism from a heroin user.
Jermann M, Hiersemenzel LP, Waespe W Drug-dependent patient with multiple
cutaneous abscesses and wound botulism
Schweiz Med Wochenschr 1999;129:1467

13. Pathogenesis All forms of disease lead to same process
Toxin absorbed into bloodstream
Irreversibly binds peripheral cholinergic synapses
Cleaves fusion proteins used by neuronal vesicles to release acetylcholine into neuromuscular junction
Blocks Acetylcholine release permanently
Results in paralysis of that muscle
Reinnervation via regeneration of axon twigs
Takes weeks to months

14. Pathogenesis
Synaptic vesicle: stores various neurotransmitters that are released at a synapse.
SNARE proteins: Soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins, establish tight membrane contact, formation of a scaffolding on which to build the machine, binding of lipid surfaces and many others.
JAMA. 2001;285:

15. Pathogenesis
JAMA. 2001;285:

16. Clinical Features Symptoms All forms same neuro symptoms
Diplopia / blurred vision
Ptosis (drooping or falling of the eyelid)
Slurred speech
Dysphagia / dry mouth
Muscle weakness

17. Clinical Features Infant botulism specifically Appears lethargic
Feeds poorly
Constipated
Weak cry
Poor muscle tone

18. Clinical Features Classic Triad Bulbar palsies summarized as "4 Ds"
Symmetric, descending flaccid paralysis with prominent bulbar palsies
Afebrile (having no fever)
Clear sensorium
Bulbar palsies summarized as "4 Ds"
Diplopia, dysarthria (speech disorder), dysphonia (impairment in ability to produce voice sound), dysphagia (dry mouth)

19. Clinical Features Symptom progression Descending paralysis
Lose head control
Lose gag – require intubation
Lose diaphragm – mechanical ventilation
Loss of deep tendon reflexes

20. Dilated or unreactive pupils
Clinical Features
Gastrointestinal/
Urinary
Neurologic
Muscular
Nausea
Dry Mouth
Symmetrical skeletal
Muscle weakness
Vomiting
Blurry vision
Respiratory muscle
paralysis
Diarrhea
Diplopia
Fatigue
Abdominal Pain
Dilated or unreactive pupils
Dyspnea
Intestinal ileus
Dysphagia
Urinary retention
Decreased gag reflex

21. Clinical Features 4 clinical forms of botulism
Food-borne (first described in 1897)
Wound (1943)
Infant (1976)
Indeterminate (1977)

22. Clinical Features Infant Occurs in children < one year old
Ingests spores, grows in bowel & release toxin
Intestinal colonization of organisms
Normal intestinal flora not developed

23. Clinical Features Indeterminate
No specific food or wound source identified
Similar to infant but occurs only in adults
Risk factor: surgical alterations of the GI tract and/or antibiotic therapy
Leads to colonization

24. Diagnosis Clinical diagnosis Diagnostic tests help confirm
Toxin neutralization mouse bioassay
Serum, stool, or suspect foods
Infant botulism
C. botulinum organism or toxin in feces

25. Diagnosis What to do at first suspicion of a case
Immediately notify public health department
Acquire therapeutic antitoxin
Send samples for diagnostic testing
Serum, vomit, gastric aspirate, suspect food, stool
Collect serum before antitoxin given
If enema required, use sterile water
Refrigerate samples and suspect foods
Get medication list to rule out anticholinesterases

26. Diagnosis Confirmation Mouse Bioassay Culture Takes 1-4 days
Available only at CDC and state public health labs
Mouse Bioassay
Type-specific antitoxin protects vs. toxin in sample
The assay can detect at minimal 0.03ng of toxin.
Culture
Fecal and gastric specimens cultured anaerobically
Results in 7 to 10 days

27. Diagnosis Differential diagnosis Unique features to help in diagnosis
Guillain-Barre, myasthenia gravis
Unique features to help in diagnosis
Disproportionate cranial nerve palsies
More hyptonia in facial muscles than below neck
Lack of sensory changes

28. Table adopted from:
Botulinum Toxin as a Biological Weapon
(JAMA. 2001;285: )

29. Treatment Supportive care
Enteral tube feeding or parenteral nutrition (via veins)
Mechanical ventilation
Treatment of secondary infections
Avoid aminoglycosides and clindamycin
Worsens neuromuscular blockade

30. Treatment Passive immunization - equine antitoxin
Antibodies to Types A, B and E toxins
Binds and inactivates circulating toxin
Stops further damage but doesn’t reverse
Administer ASAP for best outcome
Dose per package insert
Heptavalent antitoxin
Investigational
Effective against all toxins

31. Treatment Antitoxin action Antitoxin adverse effects
Food-borne botulism
Neutralizing antibody levels exceed toxin levels
Single dose adequate
Large exposure (e.g. biological weapon)
can confirm adequacy of neutralization
recheck toxin levels after treatment
Antitoxin adverse effects
Serum sickness (2-9%), anaphylaxis (2%)

32. Treatment Recovery takes weeks
Until motor axon twigs regenerate
Special groups - same treatment strategy
Children
Pregnant women
Immunocompromised

33. Prevention Natural disease Boil home-canned foods 10 minutes
Follow USDA instructions on home-canning
Restrict honey from < 1 year old
Seek medical care for wounds
Avoid injectable street drugs

34. Prevention Vaccine Botulinum pentavalent toxoid
Not available to general public
Limited supply provided by CDC
In use for laboratory workers, military
Protects vs. types A-E
Long-lasting immunity
Prohibits future therapeutic use of toxin
Onset too slow to be effective PEP

35. Infection Control Standard precautions only
No person-to-person transmission

36. Decontamination Heat all food 85ºC x 5 min Aerosolized toxin viability
Inactivate by 2 days in optimal conditions
Re-aerosolization a theoretical concern
Mask over the face may be protective
Exposed clothing and surfaces
Wash with 1:10 hypochlorite solution