From the Guidelines
No, Enterococcus species are not usually sensitive to cephalosporins. According to the most recent and highest quality study 1, Enterococci have intrinsic resistance to cephalosporins, including first-generation, second-generation, third-generation, and fourth-generation cephalosporins. This resistance occurs because these bacteria have altered penicillin-binding proteins (PBPs) with low affinity for cephalosporins, and they can continue cell wall synthesis even in the presence of these antibiotics.
Some key points to consider when treating Enterococcus infections include:
- The use of other antibiotic classes such as ampicillin (often combined with an aminoglycoside for synergy) or vancomycin (for ampicillin-resistant strains) 1
- The potential use of linezolid or daptomycin, depending on the susceptibility pattern of the specific isolate 1
- The importance of infectious disease consultation as the standard of care for managing patients with enterococcal infections 1
It's also worth noting that some Enterococcus species produce beta-lactamases that can inactivate beta-lactam antibiotics, further complicating treatment choices. The combination of ampicillin plus ceftriaxone has been reported to be effective for aminoglycoside nonsusceptible Enterococcus faecalis strains, but cephalosporins used alone are not an option for treatment of enterococcal endocarditis 1.
From the Research
Enterococcus Sensitivity to Cephalosporins
- Enterococci are characterized by natural resistance to numerous antibiotics, including cephalosporins 2, 3.
- Studies have shown that Enterococcus faecalis and Enterococcus faecium are inherently resistant to cephalosporins, which are a type of beta-lactam antibiotic 3.
- The natural resistance of enterococci to cephalosporins is due to their intrinsic properties, making them less susceptible to these antibiotics compared to other bacterial species 2.
- Acquired resistance to cephalosporins can also occur in enterococci, further reducing their effectiveness against these bacteria 3.
Antibiotic Resistance in Enterococci
- Enterococci have a wide range of intrinsic and acquired resistance determinants, making them resistant to multiple antibiotics, including cephalosporins 4, 3.
- The high genome plasticity of Enterococcus faecium allows it to acquire numerous resistances, including resistance to cephalosporins and other beta-lactam antibiotics 3.
- The diffusion of hospital-adapted strains belonging to the clonal complex CC17 has contributed to the increasing resistance of Enterococcus faecium to various antibiotics, including cephalosporins 3.
Treatment Options for Enterococcal Infections
- Due to the natural and acquired resistance of enterococci to cephalosporins, alternative treatment options are often necessary 2, 5.
- Vancomycin, daptomycin, and ampicillin-gentamicin combinations have been shown to be effective against enterococcal infections, including those caused by penicillin-resistant strains 5.
- The choice of treatment depends on the specific strain of enterococci, the mechanism of resistance, and the severity of the infection 5.