Does Linezolid (oxazolidinone antibiotic) treat Enterococcus faecalis (E. faecalis) infection?

From the Guidelines

Linezolid is effective against Enterococcus faecalis infections, and the recommended dosing for adults is 600 mg orally or intravenously every 12 hours, as stated in the most recent guidelines 1. The treatment duration may vary depending on the site and severity of infection. Linezolid is an oxazolidinone antibiotic that works by inhibiting bacterial protein synthesis, and it demonstrates good activity against gram-positive organisms including E. faecalis. When using linezolid, patients should be monitored for potential side effects including myelosuppression (particularly thrombocytopenia with prolonged use), peripheral neuropathy, and serotonin syndrome if combined with serotonergic medications. Complete blood counts should be monitored weekly, especially for treatments lasting longer than two weeks. Linezolid also has nearly 100% oral bioavailability, allowing for convenient transition from IV to oral therapy without dose adjustment when clinically appropriate. Some studies have compared the effectiveness of linezolid and daptomycin in treating VRE infections, with mixed results 1. However, the most recent and highest-quality study suggests that linezolid may be associated with a lower mortality rate compared to daptomycin 1. Key points to consider when treating Enterococcus faecalis infections with linezolid include:

• Monitoring for potential side effects
• Adjusting treatment duration based on the site and severity of infection
• Considering alternative treatments, such as daptomycin, in certain cases
• Being aware of the potential for resistance and adjusting treatment accordingly. It is essential to follow the most recent guidelines and consult with a healthcare professional to determine the best course of treatment for each individual patient. In terms of specific treatment recommendations, the guidelines suggest that linezolid is a suitable option for enterococcal infections, including those caused by vancomycin-resistant Enterococcus faecalis (VRE) 1. Overall, linezolid is a valuable treatment option for Enterococcus faecalis infections, and its use should be guided by the most recent clinical guidelines and evidence-based recommendations.

From the FDA Drug Label

The linezolid resistance in these organisms was associated with a point mutation in the 23S rRNA (substitution of thymine for guanine at position 2576) of the organism. Linezolid has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections, as described in the INDICATIONS AND USAGE section Aerobic and facultative Gram-positive microorganisms Enterococcus faecium (vancomycin-resistant strains only) Staphylococcus aureus (including methicillin-resistant strains) Streptococcus agalactiae Streptococcus pneumoniae (including multi-drug resistant isolates [MDRSP]1) Streptococcus pyogenes The following in vitro data are available, but their clinical significance is unknown At least 90% of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for linezolid. However, the safety and effectiveness of linezolid in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials Aerobic and facultative Gram-positive microorganisms Enterococcus faecalis (including vancomycin-resistant strains) Enterococcus faecium (vancomycin-susceptible strains) Staphylococcus epidermidis (including methicillin-resistant strains) Staphylococcus haemolyticus Viridans group streptococci

Linezolid treats Enterococcus faecalis (E. faecalis) infection.

• The drug label states that linezolid has been shown to be active against Enterococcus faecalis (including vancomycin-resistant strains).
• However, it is noted that the safety and effectiveness of linezolid in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials 2.

From the Research

Linezolid Treatment for Enterococcus faecalis Infection

• Linezolid is an oxazolidinone antibiotic that has been used to treat infections caused by vancomycin-resistant enterococci, including Enterococcus faecalis (E. faecalis) 3.
• However, there have been reports of linezolid resistance among E. faecalis, which can develop after long courses of linezolid therapy 4, 5, 6.
• A study found that the combination of daptomycin and linezolid had a synergistic or indifferent effect against multidrug-resistant enterococci, including E. faecalis 7.
• Risk factors for the acquisition of linezolid-resistant E. faecalis include prior linezolid use, prior clindamycin use, and previous surgery 6.
• The mortality rate for patients with linezolid-resistant E. faecalis was higher compared to controls, highlighting the need for alternative treatment options 6.

Mechanism of Resistance

• Linezolid resistance in E. faecalis has been associated with a G2576U mutation in domain V of the 23S rRNA 4, 5.
• The emergence of resistance to linezolid in E. faecalis can occur during linezolid treatment, and the isolate can revert to susceptibility after discontinuation of therapy 5.

Clinical Implications

• Linezolid sensitivity should be verified as soon as possible in patients who have recently been treated with linezolid and have an identified new systemic enterococcal isolate 4.
• Alternative treatment options, such as the combination of daptomycin and linezolid, may be effective against multidrug-resistant E. faecalis 7.
• The use of linezolid should be carefully monitored, and alternative antibiotics should be considered in patients with risk factors for linezolid-resistant E. faecalis 6.