Does Ceftaroline Fosamil Cover Gram-Positive Bacteria?
Yes, ceftaroline fosamil exhibits broad-spectrum activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), multidrug-resistant Streptococcus pneumoniae, and other streptococci. 1, 2
Spectrum of Gram-Positive Coverage
Ceftaroline is the only cephalosporin with reliable activity against MRSA, earning its designation as a fifth-generation or "advanced-generation" cephalosporin. 2 Its bactericidal action against Gram-positive organisms is mediated through high-affinity binding to essential penicillin-binding proteins (PBPs), specifically PBP2a in S. aureus and PBP2x in S. pneumoniae. 3, 4
FDA-Approved Gram-Positive Coverage
The FDA label confirms ceftaroline's activity against the following Gram-positive bacteria in clinical infections: 3
- Staphylococcus aureus (both methicillin-susceptible and methicillin-resistant isolates) 3
- Streptococcus pyogenes 3
- Streptococcus agalactiae 3
- Streptococcus pneumoniae (including penicillin- and ceftriaxone-resistant strains) 3, 5
- Streptococcus dysgalactiae (≥90% susceptible in vitro) 3
Clinical Efficacy Data
In Phase III trials for community-acquired bacterial pneumonia, ceftaroline demonstrated by-pathogen microbiological response rates of 87.3% for S. pneumoniae and 76.0% for S. aureus. 6 Against β-hemolytic streptococci, ceftaroline showed greater activity (MIC₉₀ 0.015 μg/mL) than penicillin (MIC₉₀ 0.06 μg/mL). 7
Critical Coverage Gap: Enterococcus
A major caveat is that ceftaroline has poor activity against enterococcus species and should not be used empirically for vancomycin-resistant enterococcus (VRE) infections. 1 This represents a significant limitation in its Gram-positive coverage, as enterococci are common Gram-positive pathogens in healthcare-associated infections. 1
Clinical Positioning
The Infectious Diseases Society of America lists ceftaroline as an option for MRSA skin and soft tissue infections alongside vancomycin, linezolid, and daptomycin. 2 However, ceftaroline occupies niche roles rather than first-line empiric therapy, including culture-directed treatment of documented MRSA infections when vancomycin alternatives are needed. 2
Standard Dosing
- Adults: 600 mg IV every 12 hours 2, 3
- Pediatrics: 10 mg/kg/dose IV every 8 hours (maximum 600 mg/dose) 2
Resistance Considerations
Ceftaroline is not active against Gram-negative bacteria producing extended-spectrum beta-lactamases (ESBLs), serine carbapenemases (such as KPC), class B metallo-beta-lactamases, or class C (AmpC) cephalosporinases. 3 Development of resistance to ceftaroline occurs rarely in Gram-positive bacteria. 4