Klebsiella pneumoniae

A Microbial Biorealm page on the genus Klebsiella pneumoniae

Classification

Higher order taxa

Domain: Bacteria;

Phylum: Proteobacteria;

Class: Gammaproteobacteria;

Order: Enterobacteriales;

Family: Enterobacteriaceae;

Genus: Klebsiella;

Species: K. pneumoniae

NCBI: Taxonomy

Species

Klebsiella pneumoniae

NCBI: Complete genome here

Description and significance

K. pneumoniae is a gram negative bacterium. It is rod-shaped and measures 2 µm by 0.5 µm. In 1882, Friedlander C. Uber first discovered Klebsiella to be a pathogen that caused pneumonia (8). It was isolated and sequenced from a patient in 2004. K. pneumoniae is commonly found in the gastrointestinal tract and hands of hospital personnel (3). The reason for its pathogenicity is the thick capsule layer surrounding the bacterium. It is 160 nm thick of fine fibers that protrudes out from the outer membrane at right angles (6) (5). Another site on the human body that this bacteria can be found is the nasopharynx. Its habitat is not limited to humans but is ubiquitous to the ecological environment. This includes surface water, sewage, and soil (4).

Genome structure

The complete genome was determined in 2006 at the Genome Sequencing Center at Washington University in St. Louis. The genome was named Klebsiella pneumoniae subsp. pneumoniae MGH 78578. It includes one chromosome of 5.3 Mbp. There are five plasmids, pKPN3, pKPN4, pKPN5, pKPN6, and pKPN7. Respectively, each plasmid length is 0.18 Mbp, 0.11 Mbp, 0.089 Mbp, 0.0043 Mbp, and 0.0035 Mbp. The DNA is circular. The sequence of K. pneumoniae genome was found to be closely related that of Escherichia coli K-12 (1).

Cell structure and metabolism

In 1992, K. pneumoniae could be determined apart from other species of Klebsiella. Two oligonucleotide probes and the hydroxylated fatty acid C14:0-2OH are distinctive of K. pneumoniae (2). Nitrogen fixation (nif) is utilized by K. penumoniae. This was discovered by analysis of hisD-linked nif genes and hisD-unlinked nif genes (9). It was later found that the structural gene for glutamine synthetase (G.S.), glnA, and a closely related glnG regulates the nif genes for nitrogenase (10).

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

K. pneumoniae is an important cause of human infections. (See Description and significance) Infections or diseases are usually nosocomial or hospital-acquired. In 1998, K. pneumoniae and K. oxytoca accounted for 8% of nosocomial bacterial infections in the United States and in Europe. Diseases include urinary tract infections, pneumonia, septicemias, and soft tissue infections (3). The diseases caused by K. pneumoniae can result in death for patients who are immunodeficient. CPS and LPS O side chain are two of the most important virulence factors of K. pneumoniae (7). They serve to protect the bacterium from phagocytosis by the host.

Current Research

Enter summaries of the most recent research here--at least three required

References

(1) McClelland, M., Florea, L., Sanderson, K., Clifton, S., Parkhill, J., Churcher, C., Dougan, G., Wilson, R., Miller, W. "Comparison of the Escherichia coli K-12 genome with sampled genomes of a Klebsiella pneumoniae and three Salmonella enterica serovars, Typhimurium, Typhi and Paratyphi". Nucleic Acids Res.. 2000. Volume 28(24). p. 4974–4986.

(2) Spierings, G., van Silfhout, A., Hofstra, H., and Tommassen, J. "Identification of Klebsiella pneumoniae by DNA hybridization and fatty acid analysis". International Journal of Systematic Bacteriology. 1992. Volume 42. p. 252-256.

(3) Podschun, R. and Ullmann U. "Klebsiella spp. as Nosocomial Pathogens: Epidemiology, Taxonomy, Typing Methods, and Pathogenicity Factors". Clinical Microbiology Reviews. 1998. Volume 11, No. 4. p. 589-603.

(4) Brisse, S. and Verhoef, J. "Phylogenetic diversity of Klebsiella pneumoniae and Klebsiella oxytoca clinical isolates revealed by randomly amplified polymorphic DNA, gyrA and parC genes sequencing and automated ribotyping". International Journal of Systematic and Evolutionary Microbiology. 2001. Volume 51. p. 915–924.

(5) Lawlor, M., Hsu, J., Rick, P., Miller, V. "Identification of Klebsiella pneumoniae virulence determinants using an intranasal infection model". Molecular Microbiology. 2005. Volume 58, Issue 4. p. 1054–1073.

(6) Amako, K., Meno, Y., and Takade, A. "Fine Structures of the Capsules of Klebsiella pneumoniae and Escherichia coli K1". Journal of Bacteriology. 1988. Volume 170, No. 10. p. 4960-4962.

(7) Cortés, G., Borrell, N., de Astorza, B., Gómez, C., Sauleda, J., and Albertí, S. "Molecular Analysis of the Contribution of the Capsular Polysaccharide and the Lipopolysaccharide O Side Chain to the Virulence of Klebsiella pneumoniae in a Murine Model of Pneumonia". Infection and Immunity. 2002. Volume 70, No. 5. p. 2583-2590.

(8) Friedlander C. Uber die scizomyceten bei der acuten fibrosen pneumonie. Arch Pathol Anat Physiol Klin Med 1882. 87:319-24.

(9) Hsueh CT, Chin JC, Yu YY, Chen HC, Li WC, Shen MC, Chiang CY, Shen SC. "Genetic analysis of the nitrogen fixation system in Klebsiella pneumoniae. Sci Sin. 1977. Volume 20, No. 6. p. 807-17.

(10) Espin G, Alvarez-Morales A, Merrick M. "Complementation analysis of glnA-linked mutations which affect nitrogen fixation in Klebsiella pneumoniae. Mol Gen Genet. 1981. Volume 184, No. 2. p. 213-7.

Edited by Allyson Flores, student of Rachel Larsen