Klebsiella pneumoniae

From Wikipedia, the free encyclopedia

**Klebsiella pneumoniae**
*Classifications and external resources*
ICD-10	B 96.1, G 00.8, J 15.0, P 23.6
ICD-9	041.3, 320.82, 482.0
DiseasesDB	7181
eMedicine	med/1237
MeSH	C01.252.400.310.503

iKlebsiella pneumoniae

Image:Klebsiella pneumoniae 01.png

K. pneumoniae on a MacConkey agar plate.

Scientific classification

Kingdom:	Bacteria
Phylum:	Proteobacteria
Class:	Gamma Proteobacteria
Order:	Enterobacteriales
Family:	Enterobacteriaceae
Genus:	Klebsiella
Species:	K. pneumoniae

Binomial name

Klebsiella pneumoniae
(Schroeter 1886)
Trevisan 1887

Klebsiella pneumoniae is a Gram-negative, nonmotile, encapsulated, lactose-fermenting, facultatively anaerobic, rod-shaped bacterium found in the normal flora of the mouth, skin, and intestines. It is clinically the most important member of the Klebsiella genus of Enterobacteriaceae; it is closely related to K. oxytoca from which it is distinguished by being indole-negative and by its ability to grow on both melezitose and 3-hydroxybutyrate. It naturally occurs in the soil and about 30% of strains can fix nitrogen in anaerobic condition.<ref>Postgate J (1998). Nitrogen fixation, 3rd ed.. Cambridge University Press.</ref> As a free-living diazotroph, its nitrogen fixation system has been much studied.

1 Pathogenesis
2 Treatment
3 History
4 References
5 External links

[edit] Pathogenesis

K. pneumoniae can cause bacterial pneumonia, typically due to aspiration by alcoholics, though it is more commonly implicated in hospital-acquired urinary tract and wound infections, particularly in immunocompromised individuals. Klebsiella ranks second to E. coli for urinary tract infections in older persons. It is also an opportunistic pathogen for patients with chronic pulmonary disease, enteric pathogenicity, nasal mucosa atrophy, and rhinoscleroma. Feces are the most significant source of patient infection, followed by contact with contaminated instruments. K. pneumoniae is an increasingly a nosocomial infection as antibiotic resistant strains continue to appear.

Members of the Klebsiella genus typically express 2 types of antigens on their cell surface. The first, O antigen, is a lipopolysaccharide of which 77 varieties exist. The second is K agent, a capsular polysaccharide with 9 varieties. Both contribute to pathogenicity and form the basis for subtyping.

[edit] Treatment

Klebsiella possesses a chromosomal class A beta-lactamase giving it inherent resistance to ampicillin. Many strains have acquired an extended-spectrum beta-lactamase with additional resistance to carbenicillin, ampicillin, quinolones, and increasingly to ceftazidime. The bacteria remain largely susceptible to aminoglycosides and cephalosporins. Varying degrees of inhibition of the beta-lactamase with clavulanic acid have been reported.

[edit] History

The Danish scientist Hans Christian Gram (1853–1938), developed the technique now known as Gram staining in 1884 to discriminate between K. pneumoniae and Streptococcus pneumoniae.

Klebsiella was named after the German bacteriologist Edwin Klebs (1834–1913).

Community-acquired pneumonia caused by Klebsiella pneumoniae may be called Friedländer's Pneumonia, after Carl Friedländer.