From the Guidelines
Cephalosporins do not cover Enterococcus species effectively, and alternative antimicrobials such as ampicillin, vancomycin, linezolid, or daptomycin should be used instead. The lack of coverage is due to the intrinsic resistance mechanisms in enterococci, including low-affinity penicillin-binding proteins and the production of beta-lactamases 1. Most cephalosporins, including first-generation, second-generation, third-generation, and fourth-generation, have poor activity against Enterococcus faecalis and Enterococcus faecium.
When treating infections where Enterococcus is suspected or confirmed, the following alternative antimicrobials can be used:
- Ampicillin (for susceptible strains)
- Vancomycin
- Linezolid
- Daptomycin, depending on susceptibility patterns 1. In serious infections where enterococcal coverage is needed, such as intra-abdominal infections or endocarditis, combination therapy with ampicillin plus an aminoglycoside (for synergy) or a glycopeptide like vancomycin may be required 1.
It's worth noting that some studies suggest that combination therapy with daptomycin and ampicillin or ceftaroline may be effective for enterococcal infections 1, and ceftriaxone-ampicillin combination therapy is reasonable for IE caused by aminoglycoside-resistant enterococcal strains 1. However, the most effective treatment approach should be determined based on the specific susceptibility patterns of the enterococcal strain and the severity of the infection.
From the Research
Cephalosporins and Enterococcus Coverage
- Cephalosporins are a class of antibiotics that are effective against a wide range of bacterial infections, but their coverage against enterococci is limited 2, 3.
- Third-generation cephalosporins, such as cefotaxime, have poor activity against enterococci and may even lead to enterococcal superinfection 2.
- However, some newer cephalosporins, such as ceftobiprole and ceftaroline, have shown potential activity against certain resistant enterococcal strains, including Enterococcus faecalis 4.
- It is essential to note that enterococci are inherently resistant to many antibiotics, including beta-lactams (penicillins and cephalosporins), and have developed resistance to various other antimicrobial agents 5, 3.
Treatment Options for Enterococcal Infections
- The treatment of enterococcal infections, particularly those caused by multidrug-resistant strains, is challenging and often requires the use of alternative antibiotics, such as vancomycin, linezolid, daptomycin, and tigecycline 4, 5, 6.
- The choice of antibiotic should be based on the specific strain of enterococcus, its susceptibility pattern, and the severity of the infection 5, 6.
- In some cases, combination therapy with a cell-wall active agent and an aminoglycoside may be necessary, particularly for the treatment of endocarditis 5.