From the Guidelines
Ampicillin is an effective treatment option for Enterococcus faecium infections that demonstrate sensitivity to this antibiotic, with a recommended oral dosage of 500 mg every 8 hours for uncomplicated urinary tract infections, as suggested by the most recent guidelines 1. For oral treatment of ampicillin-sensitive E. faecium, the typical adult dosage is 500 mg orally every 6 hours (or 1 gram every 8 hours for more severe infections), usually for 7-14 days depending on the site and severity of infection. Some key points to consider when treating E. faecium infections with ampicillin include:
- Antibiotic susceptibility testing should be performed to confirm sensitivity before initiating treatment 1.
- Patients should complete the full course of antibiotics even if symptoms improve before completion.
- Common side effects include diarrhea, nausea, and rash.
- Patients with penicillin allergy should avoid ampicillin and use alternative agents based on susceptibility testing.
- The effectiveness of ampicillin against sensitive E. faecium stems from its ability to inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins, ultimately causing bacterial cell death. Other treatment options for E. faecium infections include linezolid, daptomycin, tigecycline, fosfomycin, and nitrofurantoin, as outlined in the guidelines 1. However, ampicillin remains a viable option for infections that demonstrate sensitivity to this antibiotic.
From the Research
Effective Oral Antibiotics Against Enterococcus faecium
- The provided studies do not directly address oral antibiotics effective against Enterococcus faecium sensitive to ampicillin 2, 3, 4, 5, 6.
- However, some studies mention antibiotics that can be used against Enterococcus faecium, including:
- Linezolid, an oxazolidinone compound that acts by inhibiting the bacterial pre-translational initiation complex formation, has bacteriostatic activity against vancomycin-resistant E. faecium (MIC(90) = 2 to 4 microg/ml) 5.
- Quinupristin/dalfopristin, a streptogramin, which impairs bacterial protein synthesis, has bacteriostatic activity against vancomycin-resistant E. faecium (MIC(90) = 2 microg/ml) 5.
- It is essential to note that these antibiotics may not be suitable for all cases, and their use should be guided by infectious diseases consultation and based on the specific circumstances of each patient.
Limitations and Future Directions
- The current evidence does not provide a clear answer to the question of effective oral antibiotics against Enterococcus faecium sensitive to ampicillin.
- Further studies are needed to explore the potential of combination therapies and to establish clear guidelines for the treatment of Enterococcus faecium infections 3, 4, 5, 6.