Klebsiella pneumoniae in the context of "Enterobacteriaceae"

Non-motile bacteria are bacteria 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 and flagella. Coliform and Streptococci are examples of non-motile bacteria as are Klebsiella pneumoniae, and Yersinia pestis. 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, like GI mucousal cells.

Diazotrophs are organisms capable of nitrogen fixation, i.e. converting the relatively inert diatomic nitrogen (N₂) in Earth's atmosphere into bioavailable compound forms such as ammonia. Diazotrophs are typically microorganisms such as bacteria and archaea, with examples being rhizobia and Frankia and Azospirillum. All diazotrophs contain iron-molybdenum or iron-vanadium nitrogenase systems, and two of the most studied systems are those of Klebsiella pneumoniae and Azotobacter vinelandii due to their genetic tractability and their fast growth.