Cephalosporins

WIKIDRUGS ANTIBIOTICS

The Core Structure of Cephalosporins

Mechanism of Action

Cephalosporins are beta-lactams just like penicillins and work by disrupting the peptidoglycan in the cell wall of bacteria. As such they are bacteriocidal and time dependent killers.

Spectrum of Activity

Unlike penicillins it is hard to make broad generalisations about the spectrum of activity of the cephalosporin sub-groups. The two common points are that they are all stable to Staphylcococal beta lactamase and are effective against most obligate anaerobes.

First Generation Cephalosporins - Cefalexin, Cefalonium

• Active against gram positive organisms
• Active aginst many gram negatives. Pseudomonas species are resistant.

Second Generation Cephalosporins - Ceftiofur

• Very broad spectrum with very high activity against enterobacteriaeceae.
• Struggle against the most difficult gram negative organisms

Third Generation Cephalosporins - Cefoperazone

• Very active against gram negatives, especially the hardier species, including Pseudomonas
• Less active against gram positives compared to other cephalosporins; Staphylococci and enterococci can be resistant.

Fourth Generation Cephalosporins - Cefquinome

• Very broad spectrum, only the very hardiest of gram negatives aren't susceptible. It is still active againts Pseudomonas.