Klebsiella pneumoniae
From Wikipedia, the free encyclopedia
| ICD-10 | B96.1, G00.8, J15.0, P23.6 | |
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| ICD-9 | 041.3, 320.82, 482.0 | |
| DiseasesDB | 7181 | |
| eMedicine | med/1237 | |
| MeSH | C01.252.400.310.503 | |
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 K. pneumoniae on a MacConkey agar plate.
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| Klebsiella pneumoniae (Schroeter 1886) Trevisan 1887 |
Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose fermenting, facultative_anaerobic, rod shaped bacterium found in the normal flora of the mouth, skin, and intestines.[1] 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.[2] As a free-living diazotroph, its nitrogen fixation system has been much studied.
New antibiotic resistant strains of K. pneumoniae are appearing, and it is increasingly found as a nosocomial infection.
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[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.
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
Research conducted at King's College, London has implicated molecular mimicry between between HLA-B27 and two molecules in Klebsiella microbes as the cause of ankylosing spondylitis.[3]
[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.
[edit] References
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0838585299.
- ^ Postgate J (1998). Nitrogen fixation, 3rd ed.. Cambridge University Press.
- ^ Rashid T, Ebringer A (2006). "Ankylosing spondylitis is linked to Klebsiella-the evidence (Epub ahead of print)". Clin Rheumatol. PMID 17186116.
[edit] External links
- Diseases, symptoms, diagnosis of K. pneumoniae (University of Florida)
- Virtual museum of bacteria page on K. pneumoniae
- What're the complications of pneumonia? (health-cares.net)
- Klebsiella Infection (emedicine.com)
