Usage
Streptococcus faecalis, now known as Enterococcus faecalis, is a bacterium, not a medicine. It is a common cause of infections, particularly in hospitalized patients. Therefore, this entry will discuss the treatment of infections caused by E. faecalis. Antibiotics are the primary treatment.
Pharmacological Classification: Antibiotics are used to treat E. faecalis infections. Specific choices depend on the infection type and antibiotic susceptibility profile of the bacterial strain.
Mechanism of Action (of Antibiotics Used): Various antibiotics target different aspects of bacterial function. Common mechanisms employed against E. faecalis include:
* Inhibition of cell wall synthesis: Examples include ampicillin, penicillin, and vancomycin. These antibiotics interfere with peptidoglycan synthesis, a crucial component of the bacterial cell wall, leading to cell lysis.
* Inhibition of protein synthesis: Aminoglycosides (like gentamicin or streptomycin) bind to bacterial ribosomes, disrupting protein production, resulting in bacterial death.
* Disruption of cell membrane function: Daptomycin, a lipopeptide antibiotic, inserts into the bacterial cell membrane, causing depolarization and ultimately cell death.
Alternate Names
- Enterococcus faecalis (current scientific name)
- Group D Streptococcus (older classification)
How It Works (Pathogenesis of E. faecalis)
E. faecalis is a commensal bacterium found in the human gastrointestinal tract. However, it can become opportunistic, causing infections when it enters normally sterile sites like the bloodstream, urinary tract, or surgical wounds. Its virulence factors enable it to adhere to host tissues, evade the immune system, and form biofilms that enhance its resistance to antibiotics.
Pharmacodynamics/Pharmacokinetics (of Antibiotics Used): This varies considerably depending on the specific antibiotic prescribed.
- Ampicillin/Penicillin: These beta-lactam antibiotics are typically administered intravenously or orally. They are time-dependent killers, meaning their efficacy is related to the duration of time the drug concentration remains above the minimum inhibitory concentration (MIC). They are primarily renally excreted.
- Vancomycin: A glycopeptide antibiotic usually administered intravenously. It’s a time-dependent killer and eliminated renally.
- Aminoglycosides: These are concentration-dependent killers, meaning their efficacy is related to peak drug concentration. They exhibit synergistic effects when combined with cell wall-active agents against E. faecalis. They are primarily renally excreted.
- Daptomycin: Administered intravenously and is concentration-dependent. It is eliminated through both renal and non-renal pathways.
Dosage (for Antibiotics Targeting E. faecalis)
Dosage will depend on the specific antibiotic, the infection site and severity, and patient-specific factors.
Standard Dosage
The information below are some examples. The specific dosing regimen will vary based on the chosen antibiotic and patient factors. Always consult local guidelines and microbiology results to determine the appropriate antibiotic choice and dosage.
Adults:
- Ampicillin: 2 grams every 4-6 hours IV.
- Vancomycin: 15-20 mg/kg every 8-12 hours IV.
Children:
Pediatric dosing should be determined based on weight and the specific antibiotic chosen. Always consult pediatric dosing guidelines.
Special Cases:
Dose adjustments are required based on renal function, hepatic function, and other patient-specific factors.
Clinical Use Cases:
Antibiotics are chosen based on the specific clinical scenario and bacterial susceptibility.
Dosage Adjustments:
Dose adjustments are based on renal and hepatic function. Therapeutic drug monitoring may be necessary for some antibiotics like vancomycin.
Side Effects (of Antibiotics Used)
Side effects vary depending on the antibiotic. Common side effects can include gastrointestinal upset (nausea, vomiting, diarrhea), allergic reactions (rash, itching), and pain at the injection site. More serious but rarer side effects can include kidney damage (with aminoglycosides and vancomycin), hearing loss (aminoglycosides), Clostridium difficile infection, and severe allergic reactions (anaphylaxis).
Contraindications (for Antibiotics Used)
Contraindications vary depending on the specific antibiotic. For instance, penicillin is contraindicated in patients with a known penicillin allergy.
Drug Interactions (for Antibiotics Used)
Drug interactions vary by antibiotic. For example, aminoglycosides can interact with other nephrotoxic drugs, increasing the risk of kidney damage.
Pregnancy and Breastfeeding (Considerations for Antibiotics Used)
Many antibiotics are considered safe during pregnancy and breastfeeding, while others should be used with caution. Always consult resources like the FDA’s pregnancy categories and lactation databases.
Drug Profile Summary
This section would summarize the key information for the specific antibiotic chosen.
Popular Combinations
Aminoglycosides are often combined with cell wall-active agents like ampicillin or vancomycin for synergistic effects against E. faecalis, especially in serious infections like endocarditis.
Precautions
Precautions vary depending on the antibiotic chosen. Renal and hepatic function should be monitored. Drug allergies should be assessed.
FAQs
Q1: What is the recommended dosage for treating Streptococcus faecalis infections?
A: Dosage depends on the antibiotic chosen, the infection type and severity, and patient-specific factors. Consult guidelines and microbiology results for appropriate dosing.
Q2: What is the first-line treatment for E. faecalis endocarditis?
A: Ampicillin or penicillin combined with an aminoglycoside is often the first-line treatment for E. faecalis endocarditis.
Q3: What are common side effects associated with antibiotics used against E. faecalis?
A: Common side effects can include gastrointestinal upset, allergic reactions, and pain at the injection site.
Q4: What are the contraindications for ampicillin?
A: Ampicillin is contraindicated in patients with a known penicillin allergy.
Q5: What are the drug interactions to be aware of with aminoglycosides?
A: Aminoglycosides can interact with nephrotoxic drugs, increasing the risk of kidney damage.
Q6: Can antibiotics used to treat E. faecalis be used during pregnancy?
A: Consult specific resources like the FDA pregnancy categories and lactation databases for guidance on antibiotic use during pregnancy and breastfeeding.
Q7: What are the monitoring parameters when using vancomycin?
A: Vancomycin trough levels should be monitored to ensure therapeutic levels and minimize the risk of nephrotoxicity. Renal function should also be closely monitored.
Q8: What is the mechanism of action of daptomycin?
A: Daptomycin disrupts bacterial cell membrane function, causing depolarization and cell death.
Q9: What is the difference between Streptococcus faecalis and Enterococcus faecalis?
A: Enterococcus faecalis is the current and correct name. Streptococcus faecalis is an outdated name.
A: Susceptibility testing, such as broth microdilution or disk diffusion, is performed to determine the MIC of various antibiotics against the specific strain of E. faecalis causing the infection. This helps guide antibiotic selection.
