Cephalosporins: Overview (quick reference table)
Cephalosporins are β-lactam antibiotics categorized into five generations, each with varying spectrums of activity. Their coverage extends to both Gram-positive and Gram-negative bacteria, with certain generations being more effective against specific pathogens.
1. First-Generation Cephalosporins
- Examples: Cefazolin (IV), Cephalexin (oral)
- Spectrum:
- Gram-positive: Excellent coverage against MSSA and Streptococcus. No enterococcus
- Gram-negative: Limited, effective against E. coli, Proteus, and Klebsiella.
- Anaerobes: No anaerobic coverage.
- Key Notes:
- Commonly used for surgical prophylaxis and skin infections.
- Great for MSSA, but not effective against MRSA.
- No CNS penetration!
2. Second-Generation Cephalosporins
- Examples: Cefuroxime, Cefoxitin, Cefotetan
- Spectrum:
- Gram-positive: Similar to 1st generation, covers MSSA and Streptococcus. No enterococcus
- Gram-negative: Extended to include H. influenzae, Moraxella, and more E. coli strains.
- Anaerobes: Cefoxitin and Cefotetan provide some anaerobic coverage.
- Key Notes:
- Cefuroxime is commonly used for respiratory infections like pneumonia and sinusitis.
- Cefoxitin and Cefotetan are used for intra-abdominal surgeries due to their anaerobic activity (less reliable nowadays).
3. Third-Generation Cephalosporins
- Examples: Ceftriaxone, Ceftazidime
- Spectrum:
- Gram-positive: MSSA and Streptococcus (Ceftriaxone); limited Gram-positive coverage (Ceftazidime). No enterococcus
- Gram-negative: Broad, including Enterobacteriaceae, H. influenzae, and Neisseria.
- Ceftazidime covers Pseudomonas, but lacks Gram-positive activity.
- Anaerobes: No reliable anaerobic coverage.
- Key Notes:
- Ceftriaxone is the go-to for community-acquired pneumonia, meningitis, gonorrhea, and Lyme. It requires no renal dose adjustment.
- Ceftazidime is for Pseudomonas infections but lacks Gram-positive coverage.
- Ceftriaxone does not cover resistant gram negatives and Pseudomonas.
4. Fourth-Generation Cephalosporins
- Example: Cefepime (improved version of Ceftriaxone and Ceftazidime)
- Spectrum:
- Gram-positive: Similar to earlier generations, effective against MSSA and Streptococcus. No enterococcus
- Gram-negative: Broad coverage, including Pseudomonas and Enterobacteriaceae.
- Anaerobes: No anaerobic coverage.
- Key Notes:
- Excellent for severe infections, including febrile neutropenia, sepsis, and pneumonia.
- Good CNS penetration, making it effective for meningitis.
- Covers Pseudomonas, making it a great broad-spectrum option for empiric therapy.
- May cause seizures and encephalopathy with higher doses
5. Fifth-Generation Cephalosporins
- Example: Ceftaroline
- Spectrum:
- Gram-positive: Broad, including MRSA, MSSA, and Streptococcus. No enterococcus
- Gram-negative: Extended coverage but no Pseudomonas activity.
- Anaerobes: No anaerobic coverage.
- Key Notes:
- The only cephalosporin effective against MRSA.
- Used for skin infections and pneumonia, particularly when MRSA is suspected.
- No Pseudomonas or anaerobic coverage.
6. Cephalosporin/β-lactamase Inhibitor Combinations
- Examples: Ceftazidime/Avibactam, Ceftolozane/Tazobactam
- Spectrum:
- Enhanced activity against ESBL-producing Gram-negative organisms, CRE.
- Covers multi-drug resistant bacteria, including Pseudomonas.
- Key Uses:
- Reserved for serious infections due to multi-drug resistant organisms, especially in hospital settings.
Summary
- First-Generation Cephalosporins: Great for MSSA and surgical prophylaxis, with limited Gram-negative activity.
- Second-Generation Cephalosporins: Expanded Gram-negative coverage, particularly for respiratory infections. Some anaerobic coverage with Cefoxitin and Cefotetan.
- Third-Generation Cephalosporins: Broader Gram-negative activity. Ceftriaxone is ideal for meningitis and pneumonia, while Ceftazidime covers Pseudomonas.
- Fourth-Generation Cephalosporins: Cefepime, broad-spectrum, including Pseudomonas, but no anaerobic coverage. Used for severe infections.
- Fifth-Generation Cephalosporins: Ceftaroline, Effective against MRSA, but lacks Pseudomonas and anaerobic activity.
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