Enterococcus faecalis
Wesley Glick

Enterococcus faecalis is a nonmotile, gram-positive, spherical bacterium. It can be observed singly, in pairs, or in short chains, and is most often found in the large intestine of humans. It is a facultative anaerobe with a fermentative metabolism. It can often be confused with S. pneumonia, but E. faecalis contains many identification features that can be verified with testing.

E. faecalis is listed as the first to the third leading cause of nosocomial infections. Most of these infections occur after surgery of the abdomen or a puncturing trauma, but can also be linked to the increased use of IV’s and catheters, which are considered compromising devises. It is also responsible for urinary tract infections, bacterimia, endocarditis, meningitis, and can be found in wound infections along with many other bacteria.

E. faecalis was first identified as a Strep D bacterium (Streptococcus faecalis) because of its characteristic Strep D specific cell wall carbohydrate. It wasn’t until 1984, that it was classified as an Enterococcus.
E. faecalis is among the most antibiotic resistant bacteria known. It contains many natural antibiotic resistances, along with several acquired immunities transferred in R-plasmids among promiscuous bacteria. More than 25% of the E. faecalis genome is exogenously acquired, leading to its resistance to the stongest antibiotics and in some cases all antibiotics. It is also considered to be a carrier of vancomycin resistance for other genera of bacteria. With E. faecalis occurring frequently in hospital secondary infections, these multiple drug resistant strains create a scary concept.

Treatment of E. faecalis consists of a synergistic combination of aminoglycoside and cell wall-active antibiotics. In trying to prevent further antibiotic resistant strains, drug susceptibility testing is strongly recommended. New stronger, and more specific antibiotics are being developed. Multistage resistance has already been observed in laboratory testing. There are also current studies looking into inactivating cytolysin toxin.

Cytolysin toxin is responsible for rupturing a variety of target membranes and contributes to the toxicity/lethality of the infection. By inactivating the cytolysin, they are hoping to reduce number of this bacterium in circulation, while not harming many of the natural microorganisms in the body. This can be accomplished because of its highly specific targeting. Resistance to this treatment is not likely due to the fact that the organism is not being directly attacked. Since the irreversible damage of antibiotic resistance has already been created, hopefully this new therapy will make great strides in the fight against multiple drug resistant E. faecalis.

References:

http://www.life.umd.edu/classroom/bsci424/PathogenDescriptions/Enterococcus.htm
–University of Maryland
http://biology.kenyon.edu/Microbial_Biorealm/bacteria/gram-positive/enterococcus/enterococcus.htm
http://www.cdc.gov/ncidod/eid/vol4no2/huycke.htm
–Center for Disease Control
http://w3.ouhsc.edu/enterococcus/images.asp
http://www.phac-aspc.gc.ca/msds-ftss/msds146e.html
–PHAC

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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