Classification on the basis of shape all
- 1. Classification On the basis Of shape 1. Cocci Cocci are round or oval in shape. (singular coccus) For example miningococci and gonococci. cocci are further classified in to following groups on the basis of their microscopic arrangement. Diplococci: arranged in pairs Streptococci: arranged in chains Staphylococci: form grape like clusters. 2. Bacilli Bacilli are rod shaped bacteria. Forexample E. coli, Salmonela, C. Tatani. B. anthrax etc. 3.Spirochetes Spirochetes are spiral shaped they have flexible cell wall. for example, treponema, borrelia, laptospora etc. 4. Vibro Vibro are comma shaped, for example vibro cholera and vibro vulnificus etc.
- 2. Classification On the basis Of Staining 1. Gram Positive Bacteria Gram positive bacteria are those which hold the crystal violet dye after being washed with the alcohol. They are stained dark purple in color. They have this Property because they contain higher quantity of peptidoglycan in their cell wall For example. Streptococci, Clostridium, Bacillus anthrax etc. 2. Gram Negative Bacteria Gram negative Bacteria lose the crystal violet dye when they are washed with alcohol. Then the are counter stained and give pink or red color in Gram staining technique. For example E. coli, Salmonella Typhi. etc 3. Acid Fast Bacilli. Acid Fast bacilli are those which hold the dye even after being washed with an acid. These bacteria are not stained by gram staining technique. These are stained Using special type of staining procedure called
- 3. Zeihl Nelson Staining technique Classification On the basis Of Temperature 1. Thermophiles Thermophiles are those bacteira which grow best in higher temperature. for example Campylobacter jejuni which grows best at 42 degree centigrade. 2. Mesophiles Mesophiles grow best at moderate temperature. many bacteria belong to this group 3. Psychrophiles Psychrophiles Grows best at lower temperature. Classification On the basis Of Oxygen Requirement 1. Aerobes Aerobes are those bacteria which can grow only in the presence of normal concentration of oxygenFor example Mycobacterium Tuberculosis 2. Anaerobes An aerobes are those bacteria which can grow only in
- 4. absence of Oxygen for example bacteroides. 3. Facultative Anerobes These bacteria are capable of growing both in the presence and absence of Oxygen for example E. coli 4. Micro-aero phillic These bacteria require extremely low concenteration of Oxygen for their growth. Classification On the basis Of Cell Wall 1. Thick Walled Bacteria These bacteria have thick cell wall for example All gram positive and gram negative bacteria 2. Thin walled Bacteria these have thin flexible cell wall for example spirochetes 3. Wall less Bacteria e.g Mycoplasma Classification On the basis Of Spore Formation 1. Spore Forming Rods Aerobic: Bacillus Anthrax Anerobic: Clostridium
- 5. 2. Non Spore Forming Rods Non Filamentous: Corynebacterium Filamentous: Listeria Actinomyces Nocardia