Clostridium tetani

1
Pathogenic anaerobic microorganisms. Clostridia.
Biological characteristics. Laboratory
diagnostics of tetanus, botulism and gas gangrene

Vinnitsa National Pirogov Memorial Medical
University / Department of microbiology
2
General properties of Clostridia

• Taxonomy
• Family Bacillaceae.
• Genus Clostridia.
• 1. Wound infections
• 2. Enteric infections

3
Clostridia causing wound infections are

• C.tetani
• C.perfringens
• Additional agents causing gas gangrene
• C.hystolyticum
• C.novyi
• C.septicum
• C.sporogenes

4
Clostridia causing enteric infection are

• 1. C. botulinum
• 2. C.difficile
• 3. C.perfringens (serogroup A)

5
Cultivation

• Clostridia are strictly obligate anaerobic to
  aerotolerant
• The optimum temperature is 370 C, optimum pH is
  7-7.4
• Special media for anaerobs
• Robertsons cooked meat broth
• Litmus milk media.
• Kitt-Taroccis media
• Blood sugar agar

6
Virulent factors

• Exotoxins.
• Enzymes
• Capsule

7
Clostridium tetani
8
Epidemiology and pathogenesis

• Neurotoxin of C.tetani causes tetanus, a severe
  wound infection characterized by tonic muscular
  spasms, clenching of the jaw (trismus) and
  arching of the back (opistotonus)

9
Clinical forms of tetanus

1. Wounded tetanus (localized, generalized,
   cephalic)
2. Umbilical tetanus (tetanus neonatorum)
3. Postabortive tetanus
4. Cryptic tetanus

10
Laboratory diagnostics of tetanus

1. Microscopy
2. Culture
3. Tetanospasmin detection

11
Prophylaxis and treatment

• Adequate surgery prophylaxis (non-specific)
  Specific prophylaxis
• Treatment. horse antitoxin or human antitetanus
  immuno

12
C.perfringens
13
Pathogenesis

• Initial trauma (muscle damage, blood supply
  impairment and contamination of the soil)
• germination of clostridia releasing exotoxins
  damage necrotic tissue toxic products of tissue
  fermentation and toxemia cause severe shock and
  renal failure

14
Laboratory diagnostics

• Microscopy
• Culture method with neutralizing test

15
Prophylaxis and therapy of gas gangrene

• Surgery prophylaxis
• Passive immunization
• Therapy with corresponding antitoxin

16
Clostridia spp.
17
Closridium botulinum
18
Normal functionality of neuromuscular junction
19
Neurotoxin (botulotoxin)Mechanism of action
20
Epidemiology and pathogenesis

• 3 clinical forms of botulism
• Food poisoning
• Wound botulism
• Infant botulism

21
Pathogenesis of food borne botulism

• Food borne botulism is due to ingestion of
  preformed toxin, usually, in home-canned
  vegetables, fungi, meat.
• Incubation period is about 12-36 hours.
• Toxin is absorbed in the small intestine
• then it reaches to nervous system with blood
  stream,
• and binds to receptor site at the neuromuscular
  synapses of cranial and peripheral motor neurons,
• resulting in blocking nerve impulse transmission
• Clinical symptoms nausea, vomiting, thirst
  (enteric symptoms), double or blurred vision,
  dilatated pupils, slurred speech, dryness and
  pain in the throat, severe weakness, and
• Death may be due to respiratory or cardiac
  failures

22
symmetric descending paralysis
23
Laboratory diagnostics

1. Microscopy
2. Detection of botulotoxin (neutralizing test in
   animals)

24
Detection of botulotoxin in the samples with ELISA