This document discusses the classification of bacteria based on morphology, gram staining, flagella, and spore formation. Bacteria are classified as cocci, bacilli, mycoplasma, spirilla, or actinomycetes based on their shape and arrangement. Gram staining distinguishes between gram positive and gram negative bacteria based on cell wall composition. Flagella classification is based on number and location of flagella. Spore formation separates bacteria into spore forming or non-spore forming types.

3. CLASSIFICATION OF
BACTERIA

4. BASED ON SEVERAL MAJOR
PROPERITIES
• Morphology
• Flagella
• Gram staining
• Spore Formation

5. CLASSIFICATION OF BACTERIA ON
THE BASIS OF MORPHOLOGY
1. Coccus:
• These bacteria are spherical or oval in shape
• On the basis of arrangement, cocci are further classified as-
i. Diplococcus: coccus in pair. E.g., Neissseria gonorrhoae,
Pneumococcus
ii. Streptococcus: coccus in chain. E.g.. Streptococcus salivarius
iii. Staphylococcus: coccus in bunch. E.g.. Staphylococcus aureus
iv. Tetrad: coccus in group of four.
v. Sarcina: coccus in cubical arrangement of cell. E.g.. Sporosarcina

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2. Bacilli:
• These are rod shaped bacteria
• On the basis of arrangement, bacilli are further classified as-
i. Single bacillus: E.g. Bacillus cereus
ii. Coccobacilli: E.g.. Brucella
iii. Streptobacillus: chain of rod shape bacteria: E.g.. Bacillus subtilis,
iv. Diplobacillus: E.g. Moraxella bovis
v. Palisades: Corynebacterium dephtherae

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3. Mycoplasma
• They are cell wall lacking bacteria
• Also known as PLO (Pleuropneumonia like organism)
• E.g. Mycoplasma pneumonia
4. Spirillus:
• They are spiral shaped bacteria
• E.g. Triponema palladium

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5. Rickettsia and Chlamydia:
• They are obligate intracellular parasites resemble more closely to
viruses than bacteria
6. Actinomycetes:
• They have filamentous or branching structure
• They resemble more closely to Fungi than bacteria
• Example: Streptomyces

13. CLASSIFICATION OF BACTERIA ON THE
BASIS OF GRAM STAINING
1. Gram positive bacteria:
• cell wall of these bacteria is composed of peptidoglycan layer only.
• They give purple color on staining
• E.g. Staphylococcus, Streptococcus, micrococcus
2. Gram negative bacteria:
• cell wall of these bacteria is composed of Peptidoglycan and outer
membrane.
• They give pink color on staining
• E.g.. E. coli, Salmonella

16. CLASSIFICATION OF BACTERIA ON THE
BASIS OF FLAGELLA
1. Monotrichous bacteria:
• bacteria having single flagella in one end of cell.
• E.g. Vibrio cholera, Pseudomonas aeruginosa
2. Lophotrichous bacteria:
• bacteria having bundle of flagella in one end of cell.
• E.g. Pseudomanas fluorescence
3. Amphitrichous bacteria:
• bacteria having single or cluster of flagella at both end of cell.
• E.g. Aquaspirillium

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4. Peritrichous bacteria:
• bacteria having flagella all over the cell surface.
• E.g. E.coli, Salmonella, Klebsiella
5. Atrichous bacteria:
• bacteria without flagella.
• E.g. Shigella

19. Classification of bacteria on the basis of Spore
1. Spore forming bacteria:
• Those bacteria that produce spore during unfavorable condition.
• These are further divided into two group
i. Endospore forming bacteria:
• Spore produced within the bacterial cell.
• Bacillus, Clostridium, Sporosarcina etc.
ii. Exospore forming bacteria:
• Spore produced outside the cell
• Methylosinus

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2. Non sporing bacteria:
• those bacteria which do not produce spore.
• E.g.. E. coli, Salmonella