Introduction For Motility of Bacteria
Table of Contents
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
- Hanging drop preparation is the preferred method of motility test of bacteria.
- Wet mount preparation is also useful for the motility test of bacteria.
- Enterococcus casseliflavus and E. gallinarum are motile.
- 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.
- Bacillus spp. should be motile but a lack of motility could indicate Bacillus anthracis.
- Yersinia enterocolitica is motile at 25°C but non-motile at 35°C.
- Acinetobacter species are non-motile.
- Non-fermenting, gram-negative rods, and Enterobacteriaceae vary in their motility.
- Wet mount preparation of broth is also a method of motility test.
- Agar-based motility tests of bacteria are SIM, TSI, and MIU tests.
Motility of Bacterial Videos
- Motile bacteria under the hanging drop preparation