Enterococcus faecalis

Taxobox
color = lightgrey
name = "Enterococcus faecalis"

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image_width = 240px
image_caption = "Enterococcus faecalis" as viewed through a scanning electron microscope
regnum = Bacteria
phylum = Firmicutes
classis = Bacilli
ordo = Lactobacillales
familia = Enterococcaceae
genus = "Enterococcus"
species = "E. faecalis"
binomial = "Enterococcus faecalis"
binomial_authority = (Orla-Jensen 1919)
Schleifer & Kilpper-Bälz 1984

"Enterococcus faecalis" – formerly classified as part of the Group D "Streptococcus" system – is a Gram-positive commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals.cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | pages = p. 294––5 | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 ] A commensal organism like other species in the genus "Enterococcus", "E. faecalis" can cause life-threatening infections in humans, especially in the nosocomial (hospital) environment, where the naturally high levels of antibiotic resistance found in "E. faecalis" contribute to its pathogenicity.

Physiology

"E. faecalis" is a non-motile microorganism and facultatively anaerobic; it ferments glucose without gas production, and does not produce a catalase reaction with hydrogen peroxide. "E. faecalis" displays gamma hemolysis (γ-hemolysis). It produces a reduction of litmus milk, but does not liquefy gelatin. Growth of nutrient broth is consistent with being facultatively anaerobic.

Pathogenesis

"E. faecalis" can cause endocarditis, as well as bladder, prostate, and epididymal infections; nervous system infections are less common.cite book | author = Pelletier LL | title = Microbiology of the Circulatory System. "in:" Baron's Medical Microbiology "(Baron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=Lancefield&rid=mmed.section.5077 | isbn = 0-9631172-1-1 ]

Antibacterial resistance

"E. faecalis" is resistant to many commonly used antimicrobial agents (aminoglycosides, aztreonam, cephalosporins, clindamycin, the semi-synthetic penicillins nafcillin and oxacillin, and trimethoprim-sulfamethoxazole). Resistance to vancomycin is also becoming more common. [cite journal |author=Amyes SG |title=Enterococci and streptococci |journal=Int. J. Antimicrob. Agents |volume=29 Suppl 3 |issue= |pages=S43–52 |year=2007 |month=May |pmid=17659211 |doi=10.1016/S0924-8579(07)72177-5 |url=http://linkinghub.elsevier.com/retrieve/pii/S0924-8579(07)72177-5] [cite journal |author=Courvalin P |title=Vancomycin resistance in gram-positive cocci |journal=Clin. Infect. Dis. |volume=42 Suppl 1 |issue= |pages=S25–34 |year=2006 |month=January |pmid=16323116 |doi=10.1086/491711 |url=http://www.journals.uchicago.edu/doi/abs/10.1086/491711?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov] Exposure to cephalosporin is a particularly important risk factor for colonization and infection with enterococci.

Historical

Prior to 1984, enterococci were members of the genus "Streptococcus": thus "E. faecalis" was known as "Streptococcus faecalis".cite journal | author = Schleifer KH; Kilpper-Balz R | title = Transfer of "Streptococcus faecalis" and "Streptococcus faecium" to the genus "Enterococcus" nom. rev. as "Enterococcus faecalis" comb. nov. and "Enterococcus faecium" comb. nov | journal= Int. J. Sys. Bacteriol. | year= 1984 | volume= 34 | issue= | pages= 31–34 | url= ]

References