Motility in a bacteria is because of the flagella and types of flagellar arrangement. Gram-negative bacteria are classified based on their shapes. These are – bacilli, cocci, spirilla. Gram-negative bacteria are considered pathogenic to humans. They cause infections in humans which include wound infection, blood-stream infection, pneumonia, etc. Some of the commonly known diseases caused by Gram-negative bacteria are typhoid fever, cholera, shigellosis etc.

Gram-negative bacterial infections are caused by E.coli, Klebsiella, Pseudomonas aeruginosa, etc. There are many different types of motile Gram-negative bacteria, but we will be focusing on bacilli. Gram-negative bacilli are motile and they can do so by using their own energy for movement. Below is the list of motile Gram-negative bacilli :

Pseudomonas – These are aerobic motile Gram-negative bacilli that are non-enteric. They have a tail-like structure called flagella which helps them to move around. There are almost 140 types of Pseudomonas which are found in soil, water and plants

Escherichia – These are enteric coliform Gram-negative bacilli that are motile. They have helical-thread-like structures known as flagella for their movement. They move in a clockwise or anticlockwise direction with the help of a rotary motor present at the base of the flagellum.

Proteus – They are enteric Gram-negative bacilli that are facultative anaerobic, but are not coliforms. They are motile in nature and show swarming motility with their peritrichous flagella.

Related Links:

• Structure, Types and Function of Flagella
• Motile and Non-Motile Bacteria – Examples

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