ID Board Review/Antimicrobial Therapy/Antibacterials/β-Lactams/Cephalosporins

Cephalosporins are a large and varied class of antibiotics that is conceptually split into five different "generations." As the generations progress, so do their gram-negative coverages.

First Generation

The 1st generation has a fair amount of gram-positive coverage (including S. aureus) with very basic gram-negative coverage. This is why 1st generation cephalosporins are often used for surgical prophylaxis to prevent skin/surgical site infections.

• Cefazolin (Ancef)
• Cefalexin (Keflex)

Second Generation

The 2nd generation has less gram-positive coverage than the 1st generation, but has better gram-negative coverage.

• Cefuroxime
• Cefoxitin

Third Generation

The 3rd generation has more gram-negative coverage than the 2nd generation, but less gram-positive coverage. Ceftazidime stands out as the only 3rd generation cephalosporin with antipseudomonal coverage.

• Ceftriaxone (Rocephin)
• Cefdinir (Omnicef)
• Cefpodoxime (Vantin)
• Cefixime
• Cefotaxime
• Ceftazidime Antipseudomonal

Fourth Generation

The 4th generation, while small, has good pseudomonal spp coverage (hence why many patients are started on a 4th generation cephalosporin, then de-escalated once pseudomonas is ruled out).

• Cefepime

Fifth Generation

The 5th generation has the same gram-negative coverage as the 3rd and 4th generations, but has significantly better gram-positive coverage, including MSSA, MRSA and S. pneumoniae, and is considered to be a very broad-spectrum.

• Ceftaroline
• Ceftolozane-Tazobactam (Zerbaxa)
• Ceftobiprole-Avibactam (Avycaz)