Clostridium Tetani

Question 1

Clostridium Tetani

Answer 1

•Obligate anaerobes

–Oxygen is inhibitory to their growth

–Obtain energy exclusively by fermentation

• Sporeforming
• Found in soil

Anaerobic Gram positive Rods

Clostridium

• Cl. tetani - tetanus
• Cl. difficile – pseudomembranous colitis
• Cl. botulinum - botulism
• Cl. perfringens – gas gangrene

Question 2

Tetanus.

Answer 2

•Clostridium tetani

–Gram positive rod with bulging spores

–(tennis-racquet/drum-stick appearance) *

–anaerobe

•Spores found in:

–Soil, splinters, rusty nails *

–Bacteria in GI tract of humans & animals

•Traumatic implantation of spores into tissues with low oxygenation *

–Puncture wound

–Burns

–Non-sterile surgeries or deliveries

•On implantation – spores germinate vegetative cells potent neurotoxin - Tetanospasmin *

Question 3

Tetanus: Case presentation 1.

Answer 3

• A 12-year-old white male presents with stiffness of the jaw and neck along with inability to swallow
• 12 days ago he stepped on a rusty nail, which produced a small puncture wound; the area is now red, hard, and swollen with pus. He has been experiencing tingling sensations and spasms in his calf muscles. He has not received any immunizations within the last 10 years.
• PE:

–Jaw rigidity; facial muscle spasm; dysphagia; neck rigidity; normal deep tendon reflexes; profuse sweating;

–patient alert, apprehensive, restless, and hyperactive during PE

–Loud noise elicits painful spasms of face, neck, abdomen, and back, the latter producing opisthotonos

•Labs: CBC, CSF, blood chemistries normal.

Question 4

Physical Apperance of Tetanus.

Answer 4

Question 5

Treatment of Tetanus.

Answer 5

• There may be fractures of ribs or vertebrae with sustained spasms.
• Treatment:

–Surgical debridement of the wound

–Tetanus immune globulin intramuscularly or intrathecally

–Tetanus toxoid

–IV Metronidazole

–Diazepam; phenobarbital

Question 6

Tetanus illness is characterized by:

Answer 6

•Illness characterized by:

–Painful muscular contractions

–Periodic muscle spasms

Question 7

The individuals at risk for Cl. Tetanus

Answer 7

•Individuals at high risk:*

–Those with inadequate vaccine-induced immunity*

–Neonates born to unvaccinated mothers (no passive immunity conferred to baby from mother) *

Question 8

Cl. Tetani Pathogenesis

Answer 8

•Spores gain access to tissue (contaminated wound)

•Low oxidation-reduction potential (dead/devitalized tissue)

• Spores germinate → vegetative cells (gram positive rods)
• Secrete tetanospasmin * →

–carried retrograde intra-axonally to CNS + carried in blood

•Acts on motor neurons in CNS

•Blocks release of inhibitory neurotransmitters glycine and GABA (gamma-aminobutyric acid) *

•Unrestrained excitation of motor neurons

•Leads to unopposed muscle contractions and spasms (tetanospasms) → Spastic paralysis *

Question 9

Cl. Tetani- Clinical Diseases

Answer 9

Onset : from a few days to 3-4 weeks (more rapid the onset the poorer the prognosis)

3 clinical forms: general, localized and cephalic (rare)

•Generalized tetanus:*

–Spasms of masseter muscles -trimus/lockjaw –Sustained contraction of facial muscles – risus sardonicus

–Persistent back spasms - opisthotonus

–Drooling, sweating, irritabililty

•Localized tetanus:

–Spasm and increased muscle tone confined to area near wound

•Cephalic tetanus:

–Primary site of infection - head, very poor prognosis

•Neonatal tetanus:*

–Unhygenic conditions during birth and improper umbilical care practices

–Initial local infection of umbilical stump becomes generalized

–Mortality rate 90%

Question 10

Tetanus- Diagnosis

Answer 10

•Clinical diagnosis, * based on:

–History of trauma and no previous tetanus immunization

–Clinical presentation

• Blood cultures and tetanus antibody tests – often negative
• Wound cultures are positive in only 30% cases

–Organism obtained in culture tested for toxin production (only done in reference labs)

Question 11

Tetanus- Treatment

Answer 11

Immediate Prophylaxis

•Tetanus human immune globulin (tetanus antitoxin) *

–Within 72 hours of puncture wound

–Passive immunization (antibodies to tetanus given→ bind toxin in tissues)

•Debridement of wound – removes organism, spores*

•Metronidazole given – kills bacteria *

•Tetanus toxoid*

–active immunization should be given

–Those who have no history of immunization or have not had a booster in last 5 years

•Prevention of tetanus – get immunized (3 shots -tetanus toxoid) and boosters every 10 years

–DtaP, DPT