Corynebacterium jeikeium

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A Microbial Biorealm page on the genus Corynebacterium jeikeium

Classification

Higher order taxa

Domain: Bacteria

Phylum: Actinobacteria

Class: Actinobacteria

Sub-Class: Actinobacteridae

Order: Actinomycetales

Family: Corynebacterineae

Genus: Corynebacterium

Species: jeikeium

Genus

Corynebacterium jeikeium strain K411

Description and significance

Corynebacteria are gram positive, catalase-positive, aerobic, mostly non-motile rods. Corynebacterium jeikeium, an opportunistic pathogen, commonly colonizes in the skin, especially in immunocompromised hosts. Because of its broad-spectrum resistance to antimicrobial agents, the susceptibility of C. jeikeium strains is studied to a wide range of antibiotics. The strains were separated into two groups depending on the susceptibility to erythromycin, with one group representing resistant organism and the other representing susceptible organisms.

Genome structure

The genome of C. jeikeium K411 consists of a circular chromosome of 2,462,499 base pairs, and around 14,000 of them are bacteriocin-producing plasmids. Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strains. The chromosome of C. jeikeium K411 contains more than two thousand predicted coding sequences, 52% of which were considered to originate from the same ancestor as in the Corynebacterium glutamicum, Corynebacterium efficiens, and Corynebacterium diphtheriae genomes.

Cell structure and metabolism

Corynebacterium jeikeium is a "lipophilic" bacterial species, meaning its growth is generally enhanced by the presence of lipids. Anaylyses of the genome sequence indicated that this feature most likely originated from the absence of fatty acid synthase, which leads to lipids becoming an essential nutritional requirement.

Fatty acids are building blocks for the synthesis of cell walls, which are organized with other lipids to form a permeable barrier that contributes to the natural resistance of C. jeikeium to different types of antibiotics. Another special metabolic feature in C. jeikeium is their utilization of carbohydrates. Since the components of phosphotranferase systems (PTS) are not encoded by C. jeikeium, carbohydrate uptake may be mediated by a putative sodium:solute symporter, or by putative sugar-specific ATP-binding cassette(ABC) transporter. The restricted carbohydrate use reflects their adaptation to the availability of nutrients in the predominantly colonized areas of human skin.

Ecology

Corynebacterium jeikeium is commonly found in the human skin flora. Over colonization of C. jeikeium occurs in severely immunocompromised hosts, which cause infections, especially in patients with skin disruption.

Pathology

Corynebacterium jeikeium is a multidrug-resistant bacteria of the human skin flora that causes infection in severely immunocompromised patients with indwelling medical devices. This pathogenic characteristic is particularly common in neutropenic patients with intravasular catheter, prolonged neutropenia, and/or those undergoing multiple antibiotic regiments.

Patients who are diagnosed with Corynebacterium jeikeium show signs of normal bacterial infection such as fever. The predicted virulence factors of Corynebacterium jeikeium are mainly involved in ensuring the availability of exogenous fatty acids by damaging the host tissue. Studies done on the presence of plasmids in C. jeikeium have shown that, instead of extrachromosomal DNA, it's the bacterial chromosome that encode most of the multiresistance phenotype.

Application to Biotechnology

Reasearch has not found any useful compounds or enzymes produced by C. jeikeium; however, its metabolic features have provided the fundamental understanding of multidrug-resistant bacteria.

Current Research

1. The most current research done in 2005 by Tauch et al. presented "the complete genome sequence and bioinformatics analysis of multiresistant clinical isolate C. jeikeium K411" from bone marrow transplant patients who received immunosuppressive therapy and broad-spectrum antibiotics. The results allowed us to understand not only the physiology and lifestyle of C. jeikeium, but also "the molecular and biochemical basis for multiresistance as well as the pathogenic potential of this clinically important species".

2. Another study on the multidrug-resistant characteristic of C. jeikeium was done by Rosato et al. in 2001. This study focused on the susceptibility of clinical strains to a range of antimicrobial agents. "The strains were separated into two groups depending on the susceptibility to erythromycin (ERY)." Even though the molecular basis was not completely understood, the results of the study indicated that the phenotype of multidrug resistance was a result of the accumulation of individual genetic events.

3. C C Wang et al. also studied C. jeikeium bacteremia in bone marrow transplant patients who had indwelling catheters. The results showed that removal is not necessary to rid the infection as long as patients are treated with vancomycin.

References

C C Wang, D Mattson and A Wald. February 2001. " Corynebacterium jeikeium bacteremia in bone marrow transplant patients with Hickman catheters". Proceedings of Nature.com, Volume 27, Number 4, Pages 445-449

Adriana E. Rosato,† Bonnie S. Lee, and Kevin A. Nash* 2001. "Inducible Macrolide Resistance in Corynebacterium jeikeium" Proceedings of Antimicrobial Agents and Chemotherapy, vol.45

Andreas Tauch, Olaf Kaiser, Torsten Hain, Alexander Goesmann, Bernd Weisshaar, Andreas Albersmeier, Thomas Bekel, Nicole Bischoff, Iris Brune, Trinad Chakraborty, Jörn Kalinowski, Folker Meyer, Oliver Rupp, Susanne Schneiker, Prisca Viehoever, and Alfred Pühler. 2005. "Complete Genome Sequence and Analysis of the Multiresistant Nosocomial Pathogen Corynebacterium jeikeium K411, a Lipid-Requiring Bacterium of the Human Skin Flora."Proceedings of Journal of Bacteriology, vol. 187; July 2005


Edited by Michelle Ku, student of Rachel Larsen and Kit Pogliano