When you read about the structure of Bacterial cells, you might have learnt about flagella and different types of flagellar arrangements that are found in gram-negative bacteria. Most of the Gram-positive bacteria are atrichous (without flagella) so they are non-motile (Enterococcus gallinarum and E. casseliflavus/E. flavescens, the gram-positive, catalase negative cocci, generally are motile. )
So when it’s about bacterial motility, we mostly discuss Gram-negative bacteria. Motility patterns of Gram-negative bacteria is also used for the identification of bacteria.
So in this blog post, I am sharing information about characteristic motility patterns of some bacteria. You will also find information about those bacteria which become non-motile in specific conditions and about some great exceptions about motility characteristics;
Characteristics types of Bacterial Motility
|Types of Motility||Bacteria|
|Darting motility||Vibrio cholerae, Campylobacter jejuni|
|Swarming motility||Proteus spp. Clostridium tetani|
|Corkscrew motility (lashing, flexion extension motility)||Spirochete|
Alcaligenes are motile by peritrichous flagella.
Campylobacters are small delicate, spirally curved, motile Gram-negative bacteria. They show characteristic rapid corkscrew-like motility.
E. coli: Most are motile by peritrichous flagella. Alkalescens-Dispar group i.e. A-D group is non-motile.
Helicobacter: Helicobacter spp is motile by a tuft of flagella (up to 4-7 sheathed flagella are present at one end).
Listeria spp: It is motile with a characteristic tumbling and rotating motility in broth cultures. when grown at 18- 25°C but not motile or minimally motile when grown at 35-37°C.
Proteus spp: P. mirabilis and P. vulgaris are actively motile (swarming motility). Motility is not as easily observed at 35–37 ºC as at room temperature (20–28 ºC).
Pseudomonas spp: Most species of Pseudomonas are motile except Pseudomonas malli by means of one or more flagella.
Salmonella spp: Most strains are motile except Salmonella Gallinarum and Salmonella Pullorum
Spirilla are motile with groups of flagella at both ends.
Spirochaetes (Treponema, Borrelia, Leptospira): Are motile by bending and rotating body movements.
Vibrio cholerae: Vibrio cholerae are motile with the single polar flagellum and shows rapid darting (“Shooting Star”) type of motility.
Yersinia enterocolitica is motile when grown at 20- 28°C but non-motile when grown at 35-37°C.