Clostridium Question And Answers

Clostridium Long Essays

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

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.

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:

Organism causing gas gangrene Pathogenesis:

Read And Learn More: Microbiology Question and Answers

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.

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.
• (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:
Answer:

Some of the clostridial strains are as follows:

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 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.

• • 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 Short Essays

Question 1. Immunization against tetanus
(or)
Prophylaxis of tetanus.
Answer:

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.

• • 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.

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.

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:

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:

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.
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.