Clostridium Question And Answers

Clostridium Long Essays

Question 1. Discuss in detail about organisms causing gas gangrene.

Gas gangrene is caused by Clostridium perfringes.

  • It is also known as Clostridium Welchii.

The organism causing gas gangrene Morphology:

  • Cl. Perfringes is Gram-positive, capsulated and non- motile bacilli.
  • Size: large, 4 – 6 pm x 1
  • It has subterminal spores.

The organism causing gas gangrene  Culture:

  • Cl. Perfringes is anerobic.
  • It grows within a temperature range of 20 – 50°C and pH -5.5-8.

Clostridium Organism causing gas gangrene culture

The organism causing gas gangrene Biochemical Reaction:

It undergoes the following biochemical reactions.

  • Ferments glucose, lactose, sucrose and maltose.
  • It is indole negative.
  • It leads to stormy fermentation.

The organism causing gas gangrene Toxins:

Clostridium Organism causing gas gangrene Toxins

Organism causing gas gangrene Pathogenesis:

Clostridium Organism causing gas gangrene Pathogenesis.

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Clostridium Organism causing gas gangrene Pathogenesis

Organisms causing gas gangrene Diseases caused by them:

  • Gas gangrene
  • Food poisoning.
  • Necrotising enteritis.

The organism causing gas gangrene Complications:

  • Profound toxemia.
  • Prostration
  • Death due to circulatory failure.

The organism causing gas gangrene Laboratory diagnosis.

1. Specimens collected are

  • Muscles – At the edge of the affected area.
  • Tissue – In necrotic area.
  • Exudate – In deeper parts of the wounds – in active regions.

2. Cultures:

  • Aerobic and anaerobic cultures are made on fresh and heated blood agar.
  • A plate of serum or egg yolk agar with C. Perfringes antitoxin spread on one half is used for Nagler re-action.
  • Four tubes of Robortson’s cooked meat broth are inoculated and heated at 100oC for 5, 10, 15, and 20 min and then incubated at 45°C for 4 – 6 hours bacterial isolates are identified.

Clostridium - Clostridium Perfringens

Question 2. Classify Clostridium. Describe lab diagnosis and prophylaxis of gas gangrene.

Clostridium Classification:

1. Based on the shape and position of spores.

  • Central or subterminal.
  • C. Perfringes. o C. Botulinum
  • Oval and terminal -C. Tertium.
  • Spherical and terminal – C. Tetani.

2. Based on biochemical properties.

  • Both proteolytic and saccharolytic.
    • Proteolytic – predominating – C. histolyticum, C. Botulinum.
    • Saccharolytic predominating – C. Welchii.
  • (Slighly proteolytic but not saccharolytic – C. Tetani.
  • Saccharolytic but not proteolytic -Botulinum.
  • Neither proteolytic nor sacharolytic – C. Cochlearum.

2. Based on the disease.

  • Gas gangrene – C. Welchii, C. Histolyticum
  • Tetanus – C. Tetani.
  • Food poisoning – C. Botulinum.
  • Acute colitis – C. Difficile.

Clostridium Prophylaxis:

1. Surgical prophylaxis.

  • Prompt removal of all damaged tissue.
  • Irrigation of wound with an antiseptic solution.
  • Uncompromising excision of all affected tissue.

2. Antibiotics – includes.

  • Metronidazole.
  • Penicillin.
  • Sulphonamide.
  • Tetracycline.
  • Amoxycillin.

3. Antitoxin.

  • Anti-gas gangrene serum provides passive immunization.

4. Introduction of hyperbaric oxygen.

Question 3. Describe morphology, cultural characteristics, toxins liberated, and lesions produced by clostridial stains:

Some of the clostridial strains are as follows:

Clostridium Organism causing gas gangrene Clostridial strains

Question 4. Enumerate the various pathogenic Clostridia. Describe morphology, cultural characteristics and laboratory diagnosis of Clostridium tetani.

Pathogenic Clostridia:

  • C. Welchii.
  • C. Tetani.
  • C. Botulinum.
  • C. Septicum.
  • C. histolyticum.
  • C. Bifermentans.
  • C. Difficle.

Pathogenic Clostridia Morphology:

  • Cl. Tetani is gram-positive, slender bacilli.
  • Size – 4 – 8 pm x 0.5 pm.
  • It has a straignt axis, parallel sides, and rounded ends.
  • It is non-capsulated.
  • It has spherical terminal spores which gives it a drum-stick appearance.
  • It is motile and possess peritrichate flagella.
  • It occurs singly and occasionally in chains.

Pathogenic Clostridia Cultural characteristics:

  • Cl. Tetani is strictly an anaerobe.
  • It grows at 37°C and pH. 7.4.

1. Robertson cooked meat broth.

  • Growth occurs as turbidity.
  • Some gas formation occurs.
  • Meat is not digested but turns black on prolonged incubation.

2. Blood agar media.

  • Produces swarming growth.

3. Horse blood agar media.

  • Produces alpha-hemolytic colonies.
  • These develop into beta-hemolytic due to the production of hemolysin.

Pathogenic Clostridia Laboratory diagnosis:

1. Direct microscopy.

  • Gram staining shows gram-positive bacilli with drums tick appearance.

2. Culture.

  • Blood agar media.
    • The specimen is inoculated on one-half of blood agar plate at 37oC for 24 – 48 hours anaerobically.
    • It shows swarming growth.
  • Cooked meat broth (CMB)
    • The specimen is inoculated in three tubes of CMB.

Clostridium Three tubes of CMB

    • Heating kills vegetative bacteria.
    • These tubes are incubated at 37°C and subcultured on blood agar plates for 4 days.

3. Pathogenicity test.

  • Blood agar plates are used.
  • Tetanus antitoxin – 1500 units/ml is spread over one-half of the plate.
  • The suspected C. Tetani strains are stab-inoculated on each half of the plate.
  • This is incubated anaerobically for 2 days.

Pathogenicity test Result:

  • Toxigenic strains shows hemolysis around colonies in one half of the plate which does not contain antitoxin.

4. Animal inoculation.

  • 0.2 ml of 2 – 4 days old cooked meat culture is injected into the tail of 2 mice.
  • One of them that has received tetanus antitoxin – 1000 units one hour before acting as a control.

Animal inoculation Result:

  • Test animal (without antitoxin)
    • Symptoms begin within 12 – 24 hours.
    • Stiffness of tail occurs.
    • Rigidity then proceeds to one leg, another leg, the trunk, and the forelimb.
    • Death occurs within 2 days.
  • Control animal (with antitoxin)
    • No change occurs due to neutralization of toxin with antitoxin.

Clostridium - Clostridium tetani

Clostridium Short Essays

Question 1. Immunization against tetanus
Prophylaxis of tetanus.

1. Surgical prophylaxis.

  • Aims at the removal of foreign bodies, blood clot, etc.
  • It involves procedures like simple cleansing to radical excision.

2. Antibiotic prophylaxis.

  • It destroys or inhibits tetanus bacilli.
  • By this production of toxins is prevented.
  • It involves use of long-acting penicillin or erythromycin.

3. Immunization.

  • Active immunization.
    • It is achieved by tetanus toxoid which is available as a plain toxoid or adsorbed on aluminum hydroxide or phosphate (APT),
    • Three doses of 0.5 ml are given intramuscularly.

Clostridium Three doses of 0.5 mi are intramuscularly

    • Booster dose is given after 10 years.
    • Tetanus toxoid is given along with diphtheria toxoid and pertussis vaccine (DPT).
      • First dose       – 6 weeks
      • Second dose  – 10 weeks
      • Third dose      – 14 weeks
      • Booster dose  – 18 months or 5 years
  • Passive immunization.
    • It is achieved by antitetanus serum (ATS) prepared from hyperimmune horses.
    • 1500 IU of it is given intramuscularly immediately after wounding.
    • It may cause hypersensitivity, to avoid it human antitetanus immunoglobulin (HTIG) is given as 250 units.
  • Combined immunization.
    • It involves the first dose of
      • Tetanus toxoid – on one arm.
      • ATS or HTIG – on another arm.
    • Second and third doses of tetanus toxoid are given at monthly intervals.

Question 2. Tetanus OR lockjaw.

Tetanus is an acute infection of the nervous system characterized by intense activity of motor neurons and resulting in severe muscle spasms.

Tetanus Etiopathogenesis:

  • It is caused by an exotoxin produced by Clostridium tetani bacilli.
  • This acts at the synapse of the interneurons of inhibitory pathways and motor neurons to produce a blockade of spinal inhibition.

Tetanus Clinical features:

Incubation period – 6 – 10 days.

Clostridium Tetanus clinical features

Tetanus Treatment:

1. General measures.

  • Cardiopulmonary monitoring.
  • Sedation.
  • Airway maintenance.

2. Antibiotics.

  • Includes antibiotics like metronidazole.

3. Antitoxin.

  • HTIG is given, 3000 – 6000 units 1M

4. Prophylaxis – includes.

  • Wound debridement.
  • Booster doses of tetanus toxoid.

5. Unimmunised individuals are given.

  • ATS – 1500 units or
  • HTIG – 250 units.

Clostridium Short Question And Answers

Question 1. Prophylaxis and treatment of gas gangrene.

Clostridium Prophylaxis and Treatment of gangrene

Question 2. Toxins of Cl. Tetani.

1. Tetanolysis.

  • Heat labile
  • Oxygen labile
  • Causes hemolysis on blood agar.
  • May act as leukotoxin.

2. Tetanospasmin.

  • Heat labile.
  • Oxygen stable.
  • Gets rapidly destroyed by proteolytic enzymes.
  • Blocks release of neurotransmitters.
  • Neurotoxin.
  • Responsible for manifestations of tetanus.

Question 3. Nagler’s reaction.

It is a cultural characteristic of C. Welchii.

Nagler’s reaction Method:

  • Cl. Welchoi is grown on a media containing.
    • 6 % agar.
    • 5 % hide’s peptic digest of sheep blood.
    • 20% human serum or 5% egg yolk.
    • Neomycin sulphate
    • It is collected in a plate, half of which contains antitoxin.
    • It is incubated at 37oC for 24 hours.

Nagler’s reaction Result:

1. Colonies without antitoxin.

  • Surrounded by opacity.

2. Colonies with antitoxin.

  • Do not show any opacity.

Nagler’s reaction Mechanism:

  • Alpha toxin splits lecithin into phosphorylcholine and diglyceride.
  • This lipid deposit results in opacity.

Question 4. Prevention and treatment of botulism.

1. Spore germination prevented by

  • Maintaining food in an acid pH, by use of fruit preservatives.
  • Storage of food at 4°C or colder.

2. Prevention of infant botulism.

  • Preventing consumption of honey or food containing it in infants younger than 1 year.

Botulism Treatment:

  • Administration of metronidazole or penicillin
  • Trivalent botulinium antitoxin.
  • Ventilatory support.

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