Enterococcus faecium: Difference between revisions

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==Genome structure==
==Genome structure==
Describe the size and content of the genomeHow many chromosomes?  Circular or linear?  Other interesting features?  What is known about its sequence?
The sequencing of a vacomycin resistant E. faecium strain, Enterococcus faecium V583, revealed 1 circular chromosome and 3 plasmids. The chromosome consists of 3218031 base pairs and each plasmid, pTEF1, pTEF2, pTEF3, consists of 66320, 57660, and 17963 base pairs respectively.
Does it have any plasmids?  Are they important to the organism's lifestyle?
 
Two of the plasmids are pheromone-sensing conjugative plasmids. Also found was a mobile conjugative transposon that encodes vacomycin resistance. Over a quarter of E. faecium’s 3337 open reading frames are mobile and/or exogenously acquired DNAThese mobile and/or exogenously acquired DNA include seven integrated phage regions, 38 insertion elements, conjugative and composite transposons, a patheogenicity island, and integrated plasma genes. Its ability to acquire outside DNA contributes to E. faecium’s multiple drug resistance. The genes encoding vacomycin resistance in E. faecium’s are similar to E. faecalis’ vanB vancomycin-resistance conjugative transposon Tn1549 and were probably transferred as a cassette by lateral gene transfer. (5)


==Cell structure and metabolism==
==Cell structure and metabolism==

Revision as of 19:45, 4 June 2007

A Microbial Biorealm page on the genus Enterococcus faecium

Classification

Higher order taxa

Domain: Bacteria; Phylum Firmicutes; Class: Bacilli; Order: Lactobacillales; Family: Enterococcus(1)

Species

NCBI: Taxonomy

Enterococcus faecium(2)

Description and significance

E. faecium is a human pathogen that causes nosocomial bacteremia, surgical wound infection, endocarditis, and urinary tract infections. Nosocomial infections are those acquired in medial setting during treatment of a prior complaint. The normal habitat includes the gastrointestinal tract of a multitude of animals but it can also be found in the oral cavity and vaginal tract.(3) The microbe can survive for long periods of time in soil, sewage, and inside hospitals on a variety of surfaces.(6) It can grow in temperatures ranging from 10 to 45 degrees Celsius, in basic or acidic environments, and in environments which are isotonic or hypertonic.(3)

E. faecium is a Gram-positive, spherical cell that can occur in pairs or chains. The colonies formed are 1-2 mm in length and appear wet. The cells are non-motile. (8)

E. faecium is highly drug resistant and acquires its drug resistance by plasmids and conjugative transposons as well as chromosomal genes that encode resistance. Some strains have become resistant to vancomycin, penicillin, gentamicin, tetracycline, erythromycin and teicoplanin. Spread of the disease occurs between patients in hospitals due to transfer of the pathogen by hands or medical instruments. Also antibiotic use can decrease the number of other intestinal bacteria that are susceptible to the antibiotic and decrease competition for the drug resistant E. faecium. (3)

E. faecium was known as Streptococcus faecium until its name changed in 1984 due to a re-categorization. (2)

Genome structure

The sequencing of a vacomycin resistant E. faecium strain, Enterococcus faecium V583, revealed 1 circular chromosome and 3 plasmids. The chromosome consists of 3218031 base pairs and each plasmid, pTEF1, pTEF2, pTEF3, consists of 66320, 57660, and 17963 base pairs respectively.

Two of the plasmids are pheromone-sensing conjugative plasmids. Also found was a mobile conjugative transposon that encodes vacomycin resistance. Over a quarter of E. faecium’s 3337 open reading frames are mobile and/or exogenously acquired DNA. These mobile and/or exogenously acquired DNA include seven integrated phage regions, 38 insertion elements, conjugative and composite transposons, a patheogenicity island, and integrated plasma genes. Its ability to acquire outside DNA contributes to E. faecium’s multiple drug resistance. The genes encoding vacomycin resistance in E. faecium’s are similar to E. faecalis’ vanB vancomycin-resistance conjugative transposon Tn1549 and were probably transferred as a cassette by lateral gene transfer. (5)

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Ecology

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

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

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

References

1. Skerman, V.B.D., McGowan, V., and Sneath, P.H.A. (editors): "Approved lists of bacterial names." Int. J. Syst. Bacteriol. (1980) 30:225-420. Schleifer KH & Kilpper-Balz R (1984) 2. Schleifer, K.H., and Kilpper-Balz, R. "Transfer of Streptococcus faecalis and Streptococcus faecium to the genus Enterococcus nom. rev. as Enterococcus faecalis comb. nov. and Enterococcus faecium comb. nov." Int. J. Syst. Bacteriol. (1984) 34:31-34.


Edited by Morgan Feori