Microbiology - Shape of Bacteria

1. SHAPE OF BACTERIA
V.S.RASHMI PRIYEM
ULTRA’S BEST DENTAL SCIENCE COLLEGE, MADURAI

2. COCCI
 Spherical or Oval Cells.
G +ve G -ve

3. BACILLI
 Rod-Shaped Cells.
G -veG +ve

4. VIBRIOS
 Comma-Shaped, Curved Rods.
 Derive their Name from their Characteristic
Vibratory Motility.

5. SPIRILLA
 Rigid Spiral Forms.

6. SPIROCHETES
 Flexuous Spiral Forms.

7. ACTINOMYCETES
 Branching Filamentous Bacteria.
 Because of a Fancied Resemblance to the
Radiating Rays of the Sun when seen in Tissue
Lesions.

8. MYCOPLASMAS
 Bacteria that are Cell Wall Deficient.
 Hence Do Not Possess Stable Morphology.
 They Occur as Round or Oval Bodies and as Interlacing Filaments.
 When Cell Wall Synthesis becomes Defective, either Spontaneously or
as a Result of Drugs like Penicillin, Bacteria Lose their Distinctive
Shape.
 Such Cells are called Protoplasts, Spheroplasts or L Forms.

9. CELLULAR ARRANGEMENT
 Bacteria sometimes show Characteristic Cellular Arrangement or
Grouping.
 Cocci may be Arranged in Pairs (Diplococci), Chains(Streptococci), Groups
of Four (Tetrads) or Eight (Sarcina), or as Grape-like Clusters
(Staphylococci).
 Bacilli may be Arranged in Chains (Streptobacilli), Others are Arranged at
Angles to Each Other, presenting a Cuneiform or Chinese Letter Pattern
(Corynebacteria).

10. DIPLOCOCCI

11. STREPTOCOCCI

12. TETRADS

13. SARCINA

14. STAPHYLOCOCCI

15. STREPTOBACILLI

16. CUNEIFORM OR CHINESE LETTER
PATTERN (CORYNEBACTERIA)

17. CELLULAR ARRANGEMENT
 The Type of Cellular Arrangement is Determined by the
Plane through which Binary Fission Takes Place and by the
Tendency of the Daughter Cells to Remain Attached Even
After Division.