Bacterial Spectrum of Activity of Cefuroxime
Cefuroxime demonstrates broad-spectrum activity against common respiratory pathogens, with excellent coverage of Streptococcus pneumoniae (including penicillin-susceptible and intermediate strains), Haemophilus influenzae, Moraxella catarrhalis, methicillin-susceptible Staphylococcus aureus, and most Enterobacteriaceae, though it has limited activity against drug-resistant S. pneumoniae and no activity against Pseudomonas aeruginosa, enterococci, or anaerobes like Bacteroides fragilis. 1, 2
Gram-Positive Coverage
- Streptococcal species: Cefuroxime axetil has activity against S. pneumoniae similar to cefpodoxime and cefdinir, achieving approximately 75-85% coverage based on pharmacokinetic/pharmacodynamic breakpoints 1
- Staphylococci: Active against methicillin-sensitive S. aureus and S. epidermidis at concentrations ≤2 mg/L for ≥90% of strains 2, 3
- Group A, B, and G streptococci: Highly susceptible with MIC90 <0.015 mg/L 3
- Notable resistance: No activity against enterococci (group D streptococci) 4, 5
Gram-Negative Coverage
Respiratory pathogens:
- Haemophilus influenzae: Cefuroxime axetil achieves 70-85% coverage based on PK/PD breakpoints, though it is less active than cefpodoxime 1
- Moraxella catarrhalis: Approximately 50% coverage, significantly lower than third-generation cephalosporins or fluoroquinolones 1
- Both beta-lactamase-positive and beta-lactamase-negative strains are covered 6, 7
Enterobacteriaceae: Excellent activity against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella spp., and Shigella spp. with MIC90 ≤1 mg/L 2, 5, 3
Moderate activity: Enterobacter spp., Citrobacter spp., Morganella morganii, and Providencia rettgeri show variable susceptibility 2, 3
Resistant organisms: Serratia spp., indole-positive Proteus, Pseudomonas aeruginosa, and Acinetobacter spp. are resistant 5, 3
Other Pathogens
- Neisseria species: Active against N. gonorrhoeae and N. meningitidis 2, 5
- Anaerobes: Bacteroides fragilis is resistant 5
Clinical Context and Limitations
Critical limitation: Cefuroxime has no clinically significant activity against drug-resistant S. pneumoniae (DRSP), which is a major consideration when selecting empiric therapy for respiratory infections 1. This contrasts with high-dose amoxicillin (95-97% coverage) and respiratory fluoroquinolones (99% coverage) 1.
Comparative positioning: Among oral cephalosporins for respiratory pathogens, cefuroxime axetil ranks in the middle tier—superior to cefaclor and loracarbef but inferior to cefpodoxime proxetil for H. influenzae coverage 1. For S. pneumoniae, it achieves similar activity to cefdinir and cefprozil 1.
Beta-lactamase stability: Cefuroxime has activity in the presence of some beta-lactamases (both penicillinases and cephalosporinases), making it effective against beta-lactamase-producing strains of H. influenzae and M. catarrhalis 2, 6.
Pharmacokinetic Considerations
- Approximately 50% protein-bound with therapeutic concentrations achieved in pleural fluid, joint fluid, bile, sputum, bone, aqueous humor, and CSF (in meningitis) 2
- 89% excreted unchanged by kidneys, resulting in high urinary concentrations (1,150-2,500 mcg/mL after IV doses) 2
- Serum half-life approximately 80 minutes with therapeutic levels maintained for 5.3-8 hours depending on dose 2