Clostridium Tetani

Clostridium Tetani

Q. 1

All of the following are true statement regarding clostridium tetani except:

 A

The main reservoir is soil and intestine of animals and humans

 B

Herd immunity is not of much value

 C The main mode of transmission is through trauma and contaminated wound
 D

Seen commonly in winter and dry season

Q. 1

All of the following are true statement regarding clostridium tetani except:

 A

The main reservoir is soil and intestine of animals and humans

 B

Herd immunity is not of much value

 C The main mode of transmission is through trauma and contaminated wound
 D

Seen commonly in winter and dry season

Ans. D

Explanation:

Seen commonly in winter and dry season [Ref. Park 2I/e p284 (20/e p272-273); Harrison 17/e p 898] “Tetanus is common in rural areas, in warm cimates, during summer months and among males” – Harrison

Tetanus:

  • It is caused by tetanospasmin, a powerful exotoxin (second only to botulinum toxin).
  • This toxin is produced by clostridium tetani

an anaerobic, gram positive, spore hearing organism

  • Spores are ‘drum stick’ shaped
  • The bacilli is found in soil, in animal feces (mainly herbivores) & occasionally in human feces.
  • Infection is acquired by contamination of wounds with spores of C. tetani.
  • Incubation period is 6 to 10 days usually.
  • It is not transmitted from person to person and so herd immunity is not protective.
  • Immunity is acquired only by immunization. Even patients who have recovered from tetanus must be actively immunised, because the amounts of toxin responsible for the disease do not stimulate protective immunity.
  • There are 5 types of tetanus:1) Traumatic; 2)Pueperal; 3) Otogenic; 4) Idiopathic; 5) Tetanus neonatorum
  • Trismus or lock jaw, risus sardonicus (sustained spasm of facial muscles) and opisthotonus (spasm causing severe hvperextension) are main clinical features of tetanus with a morality rate of 40-80%.
  • Tetanus neonatorum is known as “8th day disease” as 1s` symptom is seen around 7th to 8th day of birth. It has a marked seasonal incidence in India. More than 50% cases occur in the month of July, August and September.
  • Active immunization is by two doses of tetanus toxoid (0.5 ml each) 1-2 months apart followed by 2 booster doses first after 1 year of initial 2 doses and second after 5 years of 1 booster dose. So total of 4 doses is required in adults including pregnant woman.

Q. 2 C.tetani is:
 A Aerobic, gram-positive, motile bacillus
 B An anaerobic, gram-negative, motile bacillus
 C An anaerobic, gram-positive, nonmotile bacillus
 D An anaerobic, gram-positive, motile bacillus
Q. 2 C.tetani is:
 A Aerobic, gram-positive, motile bacillus
 B An anaerobic, gram-negative, motile bacillus
 C An anaerobic, gram-positive, nonmotile bacillus
 D An anaerobic, gram-positive, motile bacillus
Ans. D

Explanation:

An anaerobic, gram-positive, motile bacillus


Q. 3 Clostridium tetani is:
 A Gram positive spore forming
 B Gram negative spore forming
 C Gram positive non-spore forming
 D Gram negative non-spore forming 
Q. 3 Clostridium tetani is:
 A Gram positive spore forming
 B Gram negative spore forming
 C Gram positive non-spore forming
 D Gram negative non-spore forming 
Ans. A

Explanation:

Gram positive spore forming


Q. 4

Drumstick appearence is seen in –

 A

Cl. tetani

 B

Cl. Tetanomorphum

 C

Cl. Sphenoids

 D

All

Q. 4

Drumstick appearence is seen in –

 A

Cl. tetani

 B

Cl. Tetanomorphum

 C

Cl. Sphenoids

 D

All

Ans. A

Explanation:

Ans. is ‘a’ i.e., Cl. tetani 


Q. 5

Clostridium tetani is –

 A

Gram positive bacilli

 B

Gram negative bacilli

 C

Gram positive cocci

 D

Gram negative cocci

Q. 5

Clostridium tetani is –

 A

Gram positive bacilli

 B

Gram negative bacilli

 C

Gram positive cocci

 D

Gram negative cocci

Ans. A

Explanation:

Ans. is ‘a’ i.e., Gram positive bacilli 

Clostridium tetani

.       Cl. tetani is

–      Gram positive

– Bacillus

–          Non capsulated

–          Sporing

–         The spores are spherical, terminal and bulging, giving the bacillus the characteristic ‘drumstick’ appearance. – Motile by peritrichate flagella except type IV which is non motile.

.      Culture characteristic

–          Obligatory anaerobe

– Shows swarming growth over the surface of agar. This property enables the sepration of Cl. tetani from mixed cultures. – `Filde’s technique’.

– Grows well in Robertson’s cooked meat broth.

On blood agar, a-hemolysis is produced, which later develops into 13-hemolysis, due to the production of hemolysin (tetanolysin).


Q. 6

True about clostridium tetani –

 A

It is gram +ve

 B

Drum stick appearance

 C

Obligate Anaerobe

 D

All

Q. 6

True about clostridium tetani –

 A

It is gram +ve

 B

Drum stick appearance

 C

Obligate Anaerobe

 D

All

Ans. D

Explanation:

Ans:D.)All

Clostridium tetani

  • It is a rod-shaped, anaerobic species of pathogenic bacteria, of the genus Clostridium.
  • Like other Clostridium genus species, it is Gram-positive, and its appearance on a gram stain resembles tennis rackets or drumsticks.
  • C. tetani is found as spores in soil or in the gastrointestinal tract of animals. C. tetani produces a potent biological toxin, tetanospasmin, and is the causative agent of tetanus, a disease characterized by painful muscular spasms that can lead to respiratory failure and, in up to 10% of cases, death.
  • C. tetani is a rod-shaped, obligate anaerobe.
  • During vegetative growth, the organism cannot survive in the presence of oxygen, is heat-sensitive and exhibits flagellar motility.

Q. 7

Swarming growth on culture is characteristic of which Gram positive organism ‑

 A

Clostridium welchii 

 B

Clostridium tetani

 C

Bacillus cereus

 D

Proteus mirabil is

Q. 7

Swarming growth on culture is characteristic of which Gram positive organism ‑

 A

Clostridium welchii 

 B

Clostridium tetani

 C

Bacillus cereus

 D

Proteus mirabil is

Ans. B

Explanation:

Ans. is ‘b’ i.e., Clostridium tetani 

Swarming growth

. Swarming growth is due to motility of bacteria. In young culture discrete colonies are seen but thereafter actively motile cells spread on the surface of the plate in successive waves to form a thin filmy layer in concentric circles.

.                                   Gram positive organism showing swarming growth          —>           C. tetani and Bacillus cereus

.                                   Gram negative organism showing swarming growth        -f                Proteus mirabilis and proteus vulgaris


Q. 8

All of the following statements rearding Clostridium tetani are true, except –

 A

Spores are resistant to heat

 B

Primary immunization consists of three doses

 C

Incubation period is 6-10 days

 D

None

Q. 8

All of the following statements rearding Clostridium tetani are true, except –

 A

Spores are resistant to heat

 B

Primary immunization consists of three doses

 C

Incubation period is 6-10 days

 D

None

Ans. D

Explanation:

Ans. is None 

All of the above statements regarding tetanus and Clostridium tetani are true.

Tetanus spores are highly resistant to a number of injurious agents including boiling and autoclaving for 15 minutes at 120 ( Heat) ‘ —

‘ The incubation period is usually 6-10 days ‘-

Tetanus is not transmitted from person to person ‘—-

‘ The primary series ( of active immunization) for adults consists of three doses. The first and second dose are given 4-8 weeks apart and the third dose is given 6-12 months after the second. Thereafter a booster dose is requires every 10 years’— 


Q. 9

All are features of Neonatal Tetanus except ‑

 A

Refusal to feed is common initial symptom

 B

Caused by clostridium tetani

 C

Usually occurs in 1st 2 days of life

 D

Mortality is 50-75%.

Q. 9

All are features of Neonatal Tetanus except ‑

 A

Refusal to feed is common initial symptom

 B

Caused by clostridium tetani

 C

Usually occurs in 1st 2 days of life

 D

Mortality is 50-75%.

Ans. C

Explanation:

Ans. is ‘c’ i.e., Usually occur in 1ST days of life 

Neonatal Tetanus

o It is caused by clostridium tetani

o Clinical features

          Symptoms of neonatal tetanus starts by 5-15 days after birth, never in the first 2 days of life and rarely after the age of 2 weeks. (It is commonly k/a as 8th  day disease)

          Common initial symptoms are —> Excessive unexplained crying, Refusal offeeds, Apathy

 Prognosis            Mortality rate varies from 50-75%.


Q. 10

Tetanus is caused by

 A

Cl. Tetani

 B

Cl. Welchii

 C

Cl. edematiens

 D

CI. Septicum

Q. 10

Tetanus is caused by

 A

Cl. Tetani

 B

Cl. Welchii

 C

Cl. edematiens

 D

CI. Septicum

Ans. A

Explanation:

Ans. is ‘a’ i.e., Cl. Tetani 


Q. 11

Swarming growth is shown by which gram positive bacilli:     

September 2009

 A

Clostridium tetani

 B

Clostridium welchii

 C

Proteus

 D

All of the above

Q. 11

Swarming growth is shown by which gram positive bacilli:     

September 2009

 A

Clostridium tetani

 B

Clostridium welchii

 C

Proteus

 D

All of the above

Ans. A

Explanation:

Ans. A: Clostridium tetani

C tetani is an anaerobic gram-positive rod that forms terminal spores, giving it a characteristic tennis racquet appearance. Some strains do not sporulate readily, and spores may not appear until the third or fourth day of culture. Most strains are motile with peritrichous flagella; colonies often swarm on agar plates, but some strains are nonflagellated and nonmotile.

The presence of C tetani should be suspected on isolation of a swarming rod that produces indole and has terminal spherical spores, but does not produce acid from glucose.

Toxigenic C tetani contains a plasmid that produces a toxin called tetanospasmin, but nontoxigenic strains also exist. Tetanospasmin is responsible for the infamous toxemia called tetanus.

The two animal species most susceptible to this toxemia are horses and humans.


Q. 12

Virulence factor for clostridium tetani ‑

 A

Endotoxin

 B

Tetanolysin

 C

Tetanospasmin

 D

Bacteremia

Q. 12

Virulence factor for clostridium tetani ‑

 A

Endotoxin

 B

Tetanolysin

 C

Tetanospasmin

 D

Bacteremia

Ans. C

Explanation:

Ans. is ‘c’ i.e., Tetanospasmin

Pathogenicity of CI tetani

  • Cl. tetani has little invasive property and is confined to the primary site of lodgment. Tetanus results from the action of the potent exotoxin it produces.

Toxins of CI tetani

1) Tetanolysin (Hemolysin)

  • Not relevant in the pathogenesis of tetanus.

2) Tetanospasmin (neurotoxin)

  • Responsible for tetanus
  • It is plasmid coded
  • In the brainstem and spinal cord it blocks release of the inhibitory neurotransmitter glycine and ‘y­aminobutyric acid (GABA).
  • It resembles strychnine in its effects, but it acts presynaptically, while strychnine acts postsynaptically. o Tetanus toxin and botulinum toxin resemble each other in their aminoacid sequences.

3) Nonspasmogenic, peripherally active neurotoxin

  • Its role is not known


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