Motility of Bacteria: Introduction, List of Motile and Non-motile Bacteria, Keynotes, and Related Videos

Introduction For Motility of Bacteria

Bacteria are motile due to having flagella (singular -flagellum). Some common motile bacteria are E.coli, Salmonella, Proteus, Pseudomonas, Citrobacter, and Enterobacter while non-motile are Klebsiella, Shigella, and Acinetobacter.

Motility Types of Different Microbes

S.No	Motility Types	Microbes
1.	Darting Motility	Vibrio cholerae
2.	Swarming	Proteus
3.	Stately	Clostridium
4.	Tumbling	Listeria
5.	Spinning	Fusobacterium gyrans
6.	Gliding	Mycoplasma
7.	Sluggish	Entamoeba coli

Types of Flagella

Monotrichous-Single flagellum at one end e.g. Vibrio cholerae, Caulobacter crescentus and Campylobacter

Lophotrichous-Group of flagella at one end e.g. Helicobacter

Amphitrichous- Single flagellum at both ends e.g. Alcaligenes faecalis,Aquaspirillum serpens.
Nitrosomonas,Campylobacter jejuni, and Rhodospirillum rubrum

Perotrichous-Flagella all around the body e.g. Salmonella, E. coli

Atrichous-No flagellaa e.g. Klebsiella, Shigella

List of motile bacteria

Gram-positive bacteria-

• Bacillus species ( except Bacillus anthracis)
• Enterococcus casseliflavus
• Enterococcus  gallinarum

Gram Negative bacteria

• Escherichia coli
• Proteus species
• Citrobacter species
• Enterobacter species
• Salmonella species ( except Salmonella enterica serotype gallinarum biotype pullorum)
• Serratia marcescens
• Pseudomonas aeruginosa

List of non-motile bacteria

Gram-positive bacteria

• Staphylococcus species
• Enterococcus species (Except E. casseliflavus and E. gallinarum )
• Streptococcus species

Gram-negative bacteria

• Klebsiella species
• Shigella species
• Acinetobacter species

Keynotes on Motility of Bacteria

1. Hanging drop preparation is the preferred method of motility test of bacteria.
2. Wet mount preparation is also useful for the motility test of bacteria.
3.  Enterococcus casseliflavus and E. gallinarum are motile.
4. Listeria organisms are motile at 25°C but not at 35°C, with a characteristic umbrella-shaped growth at the top of the tube. On wet mount, they exhibit tumbling motility.
5. Bacillus spp. should be motile but a lack of motility could indicate Bacillus anthracis.
6. Yersinia enterocolitica is motile at 25°C but non-motile at 35°C.
7. Acinetobacter species are non-motile.
8. Non-fermenting, gram-negative rods, and Enterobacteriaceae vary in their motility.
9. Wet mount preparation of broth is also a method of motility test.
10. Agar-based motility tests of bacteria are SIM, TSI, and MIU tests.

Motility of Bacterial Videos

• Motile bacteria under the hanging drop preparation

Proteus mirabilis motility in Wet mount of broth culture

Bacteria motility of Enterobacter aerogenes

Darting motility-positive Vibrio cholerae in the stool of Cholera patient

Tumbling Motility of Listeria monocytogenes

Brownian motion of Bacteria

Motile and non-motile bacteria under the Microscope

Bacteria Motility -Serratia marcescens

Citrobacter freundii in Wet mount of Culture Microscopy

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