Cefepime Coverage of Staphylococcus epidermidis
Cefepime does provide coverage against Staphylococcus epidermidis, but only for methicillin-susceptible strains. The FDA label explicitly states that at least 90% of S. epidermidis (methicillin-susceptible isolates only) exhibit in vitro MICs at or below the susceptible breakpoint for cefepime 1.
Spectrum of Activity Against Coagulase-Negative Staphylococci
Cefepime demonstrates activity against methicillin-susceptible S. epidermidis, with the FDA noting this organism among those with documented in vitro susceptibility, though clinical efficacy data from adequate controlled trials are limited 1.
In clinical studies of severe bacterial infections including osteomyelitis, cefepime achieved a 100% eradication rate (4/4 patients) for S. epidermidis infections 2.
Cefepime retains high potency against coagulase-negative staphylococci, whether they are beta-lactamase producers or not, as long as they remain methicillin-susceptible 3, 4.
Critical Limitations
Methicillin-resistant S. epidermidis strains are resistant to cefepime 1. This is a crucial caveat, as coagulase-negative staphylococci, particularly S. epidermidis, frequently exhibit methicillin resistance in healthcare settings.
The FDA label explicitly warns that most methicillin-resistant staphylococci are resistant to cefepime 1.
Clinical Context for S. epidermidis Infections
S. epidermidis has an established pathogenic role primarily in infections associated with prosthetic devices and indwelling catheters 5.
The prevalence of coagulase-negative staphylococcal native valve endocarditis appears to be increasing, with 8% of cases in large observational studies 6.
Practical Recommendation
Use cefepime for S. epidermidis infections only when susceptibility testing confirms methicillin susceptibility (oxacillin-susceptible). For empiric therapy of suspected S. epidermidis infections, particularly those associated with prosthetic devices or healthcare exposure where methicillin resistance is common, vancomycin or daptomycin should be considered instead until susceptibilities are known 6.