Bacterial spore

1. SPORE
Dr Nivedita Mohan

2. • Definition
• Structure of a Spore
• Sporulation
• Germination
• Shape and Position of Spores
• Demonstration of Spores
• Sporicidal Agents
• Applications

3. DEFINITION
• Spores are highly resistant resting stage of
bacteria formed in unfavourable environmental
conditions as a result of depletion of exogenous
nutrients.
• Bacterial spores are formed within the parent cell,
and are called endospores. The remaining part of
the bacterium is called sporangium.

4. STRUCTURE OF SPORE

6. SHAPE AND POSITION OF
SPORES

8. DEMONSTRATION OF SPORES
• UNSTAINED PREPARATIONS: Refractile bodies
• GRAM STAIN: Unstained refractile bodies
• MODIFIED ZIEHL NEELSON STAINING: Spore appears
red when stained with ZN Staining and 0.25% sulphuric
acid is used as decolourizer.
• SPECIAL STAINS: Schaeffer Fulton Staining, Moeller
Staining

9. SCHAEFFER-FULTON GRAM STAIN

10. SPORICIDALAGENTS
• HEAT: Autoclave, Hot Air Oven, Incineration
• ALDEHYDES: Formaldehyde, Glutaraldehyde,
Orthophthaldehyde
• Ethylene Oxide
• Oxidising Agents: Hydrogen peroxide, Peracetic Acid
(Plasma Sterilization)

11. APPLICATIONS
• Spores of certain bacteria are employed as indicators for
proper sterilization. Absence of spores after autoclaving
or processing in hot air oven indicates proper sterilization.
Spores of Geobacillus staerothermophilus are used as sterilization
control for autoclave
Spores of Bacillus atropheus are used as Sterilization control for hot air
oven.
•Spores have also been used as agents of bioterrorism
(e.g. Bacillus anthracis)

12. TO SUMMARIZE
• Spores are some of the most resistant forms of life
• Structure: Core->Cortex->Coat->Exosprium
• Stages of sporulation and germination
• Shapes an position of spores
• Demonstration of spores
• Sporicidal Agents
• Applications

13. THANK YOU