Question: How many body lengths per second can swimming bacteria travel?
About the article "Bacteria", section "Movement".

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Many bacteria can move using a variety of mechanisms: flagella are used for swimming through fluids; bacterial gliding and twitching motility move bacteria across surfaces; and changes of buoyancy allow vertical motion.
Swimming bacteria frequently move near 10 body lengths per second and a few as fast as 100.
This makes them at least as fast as fish, on a relative scale.
In bacterial gliding and twitching motility, bacteria use their type IV pili as a grappling hook, repeatedly extending it, anchoring it and then retracting it with remarkable force (>80 pN).
Flagella are semi-rigid cylindrical structures that are rotated and function much like the propeller on a ship.
Objects as small as bacteria operate a low Reynolds number and cylindrical forms are more efficient than the flat, paddle-like, forms appropriate at human-size scale.
Bacterial species differ in the number and arrangement of flagella on their surface; some have a single flagellum (monotrichous), a flagellum at each end (amphitrichous), clusters of flagella at the poles of the cell (lophotrichous), while others have flagella distributed over the entire surface of the cell (peritrichous).
The bacterial flagella is the best-understood motility structure in any organism and is made of about 20 proteins, with approximately another 30 proteins required for its regulation and assembly.
The flagellum is a rotating structure driven by a reversible motor at the base that uses the electrochemical gradient across the membrane for power.
This motor drives the motion of the filament, which acts as a propeller.
Many bacteria (such as "E. coli") have two distinct modes of movement: forward movement (swimming) and tumbling.
The tumbling allows them to reorient and makes their movement a three-dimensional random walk.
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The flagella of a unique group of bacteria, the spirochaetes, are found between two membranes in the periplasmic space.
They have a distinctive helical body that twists about as it moves.
Motile bacteria are attracted or repelled by certain stimuli in behaviors called taxes: these include chemotaxis, phototaxis, energy taxis, and magnetotaxis.
In one peculiar group, the myxobacteria, individual bacteria move together to form waves of cells that then differentiate to form fruiting bodies containing spores.
The myxobacteria move only when on solid surfaces, unlike "E. coli", which is motile in liquid or solid media.
Several "Listeria" and "Shigella" species move inside host cells by usurping the cytoskeleton, which is normally used to move organelles inside the cell.
By promoting actin polymerization at one pole of their cells, they can form a kind of tail that pushes them through the host cell's cytoplasm.
There are several ways bacteria avoid contact with phagocytes.
First, they can grow in sites that phagocytes are not capable of traveling to (e.g., the surface of unbroken skin).
Second, bacteria can suppress the inflammatory response; without this response to infection phagocytes cannot respond adequately.
Third, some species of bacteria can inhibit the ability of phagocytes to travel to the site of infection by interfering with chemotaxis.
Fourth, some bacteria can avoid contact with phagocytes by tricking the immune system into "thinking" that the bacteria are "self".
"Treponema pallidum"—the bacterium that causes syphilis—hides from phagocytes by coating its surface with fibronectin, which is produced naturally by the body and plays a crucial role in wound healing. 
"Pseudobiceros hancockanus" can travel long distances, swimming by undulating the edges of its body. 
Krill typically follow a diurnal vertical migration.
Until recently it has been assumed that they spend the day at greater depths and rise during the night toward the surface.
The deeper they go, the more they reduce their activity, apparently to reduce encounters with predators and to conserve energy.
Swimming activity in krill varies with stomach fullness.
Satiated animals that had been feeding at the surface swim less actively and therefore sink below the mixed layer.
As they sink they produce faeces which implies a role in the Antarctic carbon cycle.
Krill with empty stomachs swim more actively and thus head towards the surface.
Vertical migration may be a 2-3 times daily occurrence.
Some species (e.g., "Euphausia superba", "E. pacifica", "E. hanseni", "Pseudeuphausia latifrons", and "Thysanoessa spinifera") form surface swarms during the day for feeding and reproductive purposes even though such behaviour is dangerous because it makes them extremely vulnerable to predators.
Dense swarms can elicit a feeding frenzy among fish, birds and mammal predators, especially near the surface.
When disturbed, a swarm scatters, and some individuals have even been observed to moult instantaneously, leaving the exuvia behind as a decoy.
Krill normally swim at a pace of 5–10 cm/s (2–3 body lengths per second), using their swimmerets for propulsion.
Their larger migrations are subject to ocean currents.
When in danger, they show an escape reaction called lobstering – flicking their caudal structures, the telson and the uropods, they move backwards through the water relatively quickly, achieving speeds in the range of 10 to 27 body lengths per second, which for large krill such as "E. superba" means around .
Their swimming performance has led many researchers to classify adult krill as micro-nektonic life-forms, i.e., small animals capable of individual motion against (weak) currents.
Larval forms of krill are generally considered zooplankton. 
Calls Per Second or CPS refers to how many telephone calls can be handled in a second.CPS is one measure of the performance of Switching systems.