Clostridium

Clostridium

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

  • Gas gangrene is caused by Clostridium perfringes.
  • Gas gangrene is also known as Clostridium Welchii.

The Organism Causing Gas Gangrene Morphology:

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

Clostridium Perfringens

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.

Read And Learn More: Microbiology Question and Answers

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.

Clostridium Organism causing gas gangrene Pathogenesis

Clostridium Perfringens

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.
Answer:

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.
  • Slightly proteolytic but not saccharolytic – C. Tetani.
  • Saccharolytic but not proteolytic -Botulinum.
  • Neither proteolytic nor saccharolytic – 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 the 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:
Answer:

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.
Answer:

Pathogenic Clostridia:

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

Pathogenic Clostridia Morphology:

  • Cl. Tetani is a gram-positive, slender bacilli.
  • Size – 4 – 8 pm x 0.5 pm.
  • Pathogenic Clostridia has a straight axis, parallel sides, and rounded ends.
  • Pathogenic Clostridia is non-capsulated.
  • Pathogenic Clostridia has spherical terminal spores which gives it a drum-stick appearance.
  • Pathogenic Clostridia is motile and possesses peritrich flagella.
  • Pathogenic Clostridia 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 BloodAgar Media.

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

Clostridium Perfringens

Pathogenic Clostridia Laboratory Diagnosis:

1. Direct Microscopy.

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

2. Culture.

  • Blood Agar Media.
    • The specimen is inoculated on one-half of the blood agar plate at 37°C 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 show 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 the 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
(or)
Prophylaxis of tetanus.
Answer:

1. Surgical Prophylaxis.

  • Aims at the removal of foreign bodies, blood clots, 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 the 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

    • A 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.
Answer:

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

Clostridium Perfringens

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.
Answer:

Clostridium Prophylaxis and Treatment of gangrene

Question 2. Toxins of Cl. Tetani.
Answer:

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.
Answer:

Nagler’s Reaction 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 sulfate
    • 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 Without 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.
Answer:

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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