Non-motile bacteria are

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

species that lack the ability and structures that would allow them to propel themselves, under their own power, through their environment. When non-motile bacteria are cultured in a stab tube, they only grow along the stab line. If the bacteria are mobile, the line will appear diffuse and extend into the medium. The cell structures that provide the ability for locomotion are the

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

and

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

. Coliform and

Streptococci ''Streptococcus'' is a genus of gram-positive spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs along a sing ...

are examples of non-motile bacteria as are ''

Klebsiella pneumoniae ''Klebsiella pneumoniae'' is a Gram-negative, non-motile, encapsulated, lactose- fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar. Although found in the normal flora of the mo ...

'', and ''

Yersinia pestis ''Yersinia pestis'' (''Y. pestis''; formerly ''Pasteurella pestis'') is a Gram-negative bacteria, gram-negative, non-motile bacteria, non-motile, coccobacillus Bacteria, bacterium without Endospore, spores. It is related to pathogens ''Yer ...

''. Motility is one characteristic used in the identification of bacteria and evidence of possessing structures: peritrichous flagella, polar flagella and/or a combination of both. Though the lack of motility might be regarded a disadvantage, some non-motile bacteria possess structures that allow their attachment to

eukaryotic cells The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of li ...

, like GI mucousal cells. Some genera have been divided based upon the presence or absence of motility. Motility is determined by using a motility medium. The ingredients include motility test medium, nutrient broth powder, NaCl and distilled water. An inoculating needle (not a loop) is used to insert the bacterial sample. The needle is inserted through the medium for a length of one inch. The media tube incubated at . Bacteria that are motile grow away from the stab, and toward the sides and downward toward the bottom of the tube. Growth should be observed in 24 to 48 hours. With some species, the bacterium is inconsistent related to its motility.

References

Bacteria Bacteriology {{bacteria-stub