| Klebsiella pneumoniae | |
|---|---|
| |
| K. pneumoniae on a MacConkey agar plate | |
Scientific classification 
| |
| Domain: | Bacteria |
| Phylum: | Pseudomonadota |
| Class: | Gammaproteobacteria |
| Order: | Enterobacterales |
| Family: | Enterobacteriaceae |
| Genus: | Klebsiella |
| Species: | K. pneumoniae
|
| Binomial name | |
| Klebsiella pneumoniae (Schroeter 1886) Trevisan 1887
| |
| Subspecies | |
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 mouth, skin, and intestines,[1] it can cause destructive changes to human and animal lungs if aspirated, specifically to the alveoli, resulting in bloody, brownish or yellow colored jelly-like sputum. In the clinical setting, it is the most significant member of the genus Klebsiella of the Enterobacteriaceae. K. oxytoca and K. rhinoscleromatis have also been demonstrated in human clinical specimens. In recent years, Klebsiella species have become important pathogens in nosocomial infections.
It naturally occurs in the soil, and about 30% of strains can fix nitrogen in anaerobic conditions.[2] As a free-living diazotroph, its nitrogen-fixation system has been much-studied, and is of agricultural interest, as K. pneumoniae has been demonstrated to increase crop yields in agricultural conditions.[3]
It is closely related to K. oxytoca from which it is distinguished by being indole-negative and by its ability to grow on melezitose but not 3-hydroxybutyrate.
- ^ Ryan KJ, Ray CG, eds. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 978-0-8385-8529-0.
- ^ Postgate J (1998). Nitrogen Fixation (3rd ed.). Cambridge University Press. ISBN 978-0-521-64047-3.
- ^ Riggs PJ, Chelius MK, Iniguez AL, Kaeppler SM, Triplett EW (2001). "Enhanced maize productivity by inoculation with diazotrophic bacteria". Australian Journal of Plant Physiology. 29 (8): 829–836. doi:10.1071/PP01045.