From the Guidelines
Ertapenem is not the preferred agent for the treatment of persistent Methicillin-Sensitive Staphylococcus aureus (MSSA) bacteremia due to its limited activity against MSSA 1.
Treatment Options
- Nafcillin or oxacillin are recommended at a dose of 1.5-2 grams every 4-6 hours, with treatment duration typically ranging from 4-6 weeks 1.
- Cefazolin may be used at a dose of 1-2 grams every 8 hours, also for 4-6 weeks 1.
Key Considerations
- Ertapenem is a carbapenem antibiotic with limited activity against MSSA and is not typically used for this indication 1.
- The choice of antibiotic should be based on the severity of the infection, the susceptibility of the organism, and the clinical response of the patient 1.
- Repeat imaging studies should be performed in the patient with persistent bacteremia to identify undrained foci of infection 1.
- Antibiotics should be administered intravenously initially, but once the patient is clinically improved, oral antibiotics are appropriate for patients in whom bacteremia cleared promptly and there is no evidence of endocarditis or metastatic abscess 1.
From the FDA Drug Label
Ertapenem has in vitro activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria. The bactericidal activity of ertapenem results from the inhibition of cell wall synthesis and is mediated through ertapenem binding to penicillin binding proteins (PBPs) Gram-positive bacteria: Staphylococcus aureus (methicillin susceptible isolates only)
The treatment for persistent Methicillin-Sensitive Staphylococcus aureus (MSSA) bacteremia with Ertapenem is Ertapenem 1 g IV once daily 2.
- Key points:
- Ertapenem has in vitro activity against MSSA
- The recommended dose is 1 g IV once daily
- Ertapenem is effective against methicillin-susceptible isolates of Staphylococcus aureus
From the Research
Treatment for Persistent Methicillin-Sensitive Staphylococcus aureus (MSSA) Bacteremia with Ertapenem
- The use of ertapenem in combination with other antibiotics, such as cefazolin or oxacillin, has been described as a successful treatment for persistent MSSA bacteremia 3, 4, 5, 6.
- A multicentre, retrospective study found that combination therapy with ertapenem and standard treatment (cefazolin, oxacillin, or nafcillin) resulted in faster time to blood culture sterilization compared to standard treatment alone 3.
- In vitro and in vivo studies have demonstrated synergy between ertapenem and cefazolin against MSSA, with the combination showing bactericidal activity and enhanced clearance of bacteremia 4, 5, 6.
- The combination of ertapenem and cefazolin has been used to successfully clear refractory MSSA bacteremia, including in cases of endocarditis 4, 5, 6.
- Ertapenem plus cefazolin has also been shown to have potent activity against Staphylococcal biofilms, which may contribute to its effectiveness in treating MSSA endocarditis 6.
Comparison to Other Treatments
- A study comparing daptomycin plus oxacillin to ertapenem-based combination therapy found that the former may be an effective, well-tolerated salvage regimen for persistent MSSAB, and could represent a carbapenem-sparing option 7.
- However, the majority of the evidence suggests that ertapenem-based combination therapy is a viable option for treating persistent MSSA bacteremia, particularly in cases where standard treatment has failed 3, 4, 5, 6.
Key Findings
- Ertapenem in combination with cefazolin or oxacillin is a potential treatment option for persistent MSSA bacteremia 3, 4, 5, 6.
- The combination of ertapenem and cefazolin has been shown to have synergistic activity against MSSA, both in vitro and in vivo 4, 5, 6.
- Further studies are needed to fully evaluate the effectiveness and safety of ertapenem-based combination therapy for persistent MSSA bacteremia 3, 4, 5, 6.