Classification of bacteria

 Classification of Bacteria

Shape of bacteria

Shape of bacteria due to rigid cell wall.

On the basis of shape and arrangement, bacteria are-

1. Cocci

2. Bacilli

1. Cocci

These are spherical, round and oval shape.

Some cocci are gram positive and some are gram negative.

Types of Cocci

1. Diplococci- cocci occurs in pairs

2. Streptococci- cocci occurs in chains

3. Staphylococci- cocci in cluster

4. Tetrads- cocci occur in group of four

5. Octads - cocci occurs in group of eight

6. Micrococci- cocci in single

2. Bacilli

These are rod or stick shaped bacteria.

On the basis of arrangement of an individual organism, Bacilli are-

1. Coccobacilli, length of bacilli may be equal to its width. For example, brucella

2. Streptobacilli, bacilli occurs in form of chain. For example, lactobacilli

3. Microbacilli, bacilli occurs in single.

4. Diplobacilli, bacilli occurs in pairs.

5. Comma shaped Bacilli, appears like comma shaped, for example, vibriocholera

6. Spirilla, (single spirillum), have helical shaped with thick, rigid cell wall, non-flexible spiral forms. For example, Spirillum

7. Spirochaetes, these are slender spiral filament coil.

They are flexible

Live in soil and stagnant pools. Example , Treponema pallidium

8. Mycoplasma, theses have lack of cell wall, not posses stable shape and are pleomorphic.

9. Chinese letter pattern, example, corynebacterium