Enterococcus faecalis is a Bacteria
Yes, Enterococcus faecalis is definitively a Gram-positive bacterium that belongs to the genus Enterococcus. 1
Taxonomic Classification and Characteristics
Enterococcus faecalis is classified as:
- A Gram-positive bacterium
- Facultative anaerobic (can grow with or without oxygen)
- Part of the genus Enterococcus
- Commonly found in the gastrointestinal tract, oral cavity, and periodontal tissue 2
Clinical Significance
E. faecalis has a dual lifestyle as both a commensal organism and a pathogen:
- As a commensal: It is normally present in the human gut microbiota 3
- As a pathogen: It can cause various infections including:
E. faecalis is particularly concerning in healthcare settings due to its ability to:
- Acquire antimicrobial resistance, including vancomycin resistance (VRE) 1
- Express virulence factors such as cytolysin, a pore-forming exotoxin 4
- Invade and replicate within host cells 3
- Tolerate harsh environmental conditions including wide temperature and pH ranges 2
Antimicrobial Resistance
E. faecalis can develop resistance to multiple antibiotics:
- Ampicillin resistance
- High-level aminoglycoside resistance
- Vancomycin resistance (VRE) 1
For vancomycin-resistant E. faecalis infections, treatment options include:
- Linezolid (600 mg IV or PO every 12h) for monomicrobial infections 1
- Tigecycline (100 mg IV loading dose then 50 mg IV q12h) for polymicrobial intra-abdominal infections 1
- Daptomycin (at higher doses of 8-12 mg/kg/day) for bacteremia, sometimes in combination with β-lactams 1, 5
Biological Properties
E. faecalis possesses several notable biological characteristics:
- Ability to form biofilms
- Production of lanthionine-containing bacteriocins 4
- Metal homeostasis systems that help it respond to fluctuations in extracellular metal levels (iron, manganese, zinc, and copper) 6
- Fe-S cluster biosynthesis that is essential for anaerobic growth and gastrointestinal colonization (similar to E. faecium) 7
Clinical Implications
In intra-abdominal infections:
- E. faecalis is among the most prevalent Gram-positive bacteria isolated in intra-operative samples (15.9% of all aerobic isolates) 1
- More prevalent in hospital-acquired IAIs (22.3%) than in community-acquired IAIs (13.9%) 1
- Empirical coverage against Enterococci is generally not recommended for community-acquired IAIs but should be considered for postoperative IAIs 1
Understanding the bacterial nature of E. faecalis is crucial for appropriate antimicrobial selection and infection control strategies in clinical settings.
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