Non-Sporing Anaerobes Short Essays
Question 1. Lactobacillus.
Answer:
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.
Answer:
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.
Read And Learn More: Microbiology Question and Answers
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.
Answer:
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.
Answer:
- Penicillin.
- Tetracycline
- Chloramphenicol
- Metronidazole.
Question 3. Enumerate four non-sporing anaerobes.
Answer:
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.
Answer:
- Gram positive cocci – peptococci, peptostreptococci
- Gram negative cocci – Veillonella
- Gram positive bacilli – Clostridium
- Gram negative bacilli – Bacteroides, fusobacterium