Non-Sporing Anaerobes Question And Answers

Non-Sporing Anaerobes Short Essays

Question 1. Lactobacillus.

Lactobacilli are non-sporing, anaerobic, Gram-positive bacilli.

  • They are acidophilic and grow best at pH 5 or less.
  • They show bipolar and barred staining.
  • They are normally present in

1. Mouth.

  • Lactobacilli cause dental caries.
  • They form lactic acid by fermentation of sugar which destroys enamel and dentin.

2. Intestine.

  • L-acidophilus synthesize vitamins such as biotin, B12, K

3. Vagina.

  • Lactobacillus is called Doderleins bacilli to ferment the glycogen deposited in the vaginal epithelial cells forming lactic acid.
  • This results in highly acidic pH of the vagina.
  • They protect the adult vagina from infections.

Lactobacillus Culture:

Lactobacillus grow in media enriched with glucose or blood in the presence of 5% CO2 and at pH 6

Lactobacillus Pathogenicity:

  • Lactobacilli are non-pathogenic.
  • Involved in serious infections in immune-compromised individuals.
  • Associated with advanced dental caries.

Question 2. Bacteroides.

Bacteroides are non-sporing, non-motile, obligate anaerobes, gram-negative bacilli.

  • They possess capsular polysaccharides
  • They are pleomorphic.
  • They occur normally in the mouth, gastrointestinal, and female genital tracts.

Bacteroides Common species:

  • B. Fragilis – isolated from the large intestine.
  • B. Maleninogenicus – isolated from or pharynx, gut, and vagina.

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Bacteroides Culture:

  • Bacteroides require enriched media containing blood for growth.
  • They grow readily in brain-heart infusion agar.
  • P. Melaninogenica causes black or brown-coloured colonies.
  • It results in characteristic red fluorescence when exposed to ultraviolet light.

Diseases caused by them:

  • Peritonitis.
    • Occurs following bowel injury and pelvic inflammatory disease.
  • Brain and abdominal abscess.
  • Empyema.
  • Periodontal disease – caused by P. Gingivalis.
  • Dental root canal infections – caused by P. endodon- talis.

Non-Sporing Anaerobes Short Question And Answers

Question 1. Fusobacterium.

Fusobacterium Morphology:

  • Gram-negative bacilli.
  • Long slender rods that are wide at the center and taper towards ends.
  • Non-motile.

Fusobacterium Culture:

  • Fusobacterium are strictly anaerobes.
  • They grow on blood agar containing neomycin and vancomycin.

Fusobacterium Pathogenicity:

  • They are commensals in the mouth, gastrointestinal and genitourinary tracts

Fusobacterium Causes:

  • Head and neck infections.
  • Dental and periodontal infections.
  • Cerebral abscess.
  • Intraabdominal infections.
  • Osteomyelitis.
  • Soft tissue infection.

Question 2. Antibiotics are used against anaerobic bacteria.

  1. Penicillin.
  2. Tetracycline
  3. Chloramphenicol
  4. Metronidazole.

Question 3. Enumerate four non-sporing anaerobes.

1. Cocci.

  • Gram-positive – streptococcus.
  • Gram negative – veillonella.

2. Bacilli.

  • Gram positive – eubacterium, lactobacillus.
  • Gram negative – bacteroides, fusobacterium.

3. Spirochaetes – Treponema, borrelia.

Question 4. Name four anaerobic bacteria.

  1. Gram positive cocci – peptococci, peptostreptococci
  2. Gram negative cocci – Veillonella
  3. Gram positive bacilli – Clostridium
  4. Gram negative bacilli – Bacteroides, fusobacterium

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