Detailed Classification Of Bacteria - Microbiology

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.
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  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 oxygen For example Mycobacterium Tuberculosis
2. Anaerobes	An aerobes are those bacteria which can grow only in 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
2. Non Spore  Forming Rods	Non Filamentous: Corynebacterium Filamentous:          Listeria                             Actinomyces                             Nocardia