Question

discuss the importance of spore staining and names a few examples of bateria which are spore formers and nonspore formers

Answer 1

Answer : Spores are highly resistant resting or dormant stage of the bacteria formed in unfavourable conditions.

Main purpose of spore staining is differentiation and identification of the organism.

Spore staining helps to differentiate between bacterial spores from other vegetative cells and also differentiate spore formers from non-spore formers.

Spore characteristics are consistent within the spore-forming species and helps to identify species. For a given species, the precise position , shape and relative size of the spore are constant .

Demonstration of spores

1. Gram staining : Spores appear as unstained refractile bodies within the cells.

2. Modified Ziehl-Neelsen staining : Spores are weakly acid-fast and appear red colour when ZN staining is performed using 0.25% sulfuric acid as decolorizer.

3. Special staining techniques : Schaeffer-Fulton stain , Moeller stain ans Ashby's method ( Bacillus anthracis).

Examples of Spore forming bacteria-  

1. Bacillus genera eg. Bacillus anthracis , Bacillus cereus , Bacillus stearothermophilus , Bacillus subtilis etc.

2. Clostridium genera eg. Clostridium perfringens , Clostridium tetani , Clostridium botulinum , Clostridium difficile etc.

Examples of Non-spore forming bacteria-

A. Anaerobic bacteria

1. Gram-positive cocci eg. Peptostreptococcus , Peptococcus

2. Gram-positive bacilli eg. Bifidobacterium , Eubacterium , Propionibacterium etc.

3. Gram-negative cocci eg. Veillonella

4. Gram-negative bacilli eg. Bacteroides , Prevotella , Porphyromonas etc.

5. Spirochete eg. Treponema , Borrelia

B. Aerobic bacteria

Corynebacterium diphtheriae , Streptococcus pyogenes , Staphylococcus aureus , Neisseria meningitids etc .