Q: Why in comparison to others in same group Cefepime is considered 4th generation Cephelosporin? 


Answer: Cefepime is an extended-spectrum cephalosporin active against a broad spectrum of gram-positive and gram-negative aerobic bacteria. The gram-positive spectrum is similar to that of cefotaxime, the gram-negative spectrum is similar to that of ceftazidime, and many, though not all, organisms resistant to these two agents remain susceptible to cefepime, prompting it to have fourth-generation designation. The reason thought to be as Cefepime has a decreased propensity to induce beta-lactamases compared with other beta-lactam antibiotics.

 Cephalosporins are β-lactam antibiotics, which are grouped into four generations according to their antibiotic spectrum of activity. The first generation has mainly gram-positive activity. The second and third generation has more gram-negative activity with mostly decreased activity against gram-positive bacteria. Few examples are: 

 •First Generation: cefazolin, cefalexin, cefadroxil 
•Second Generation: cefamandole, cefoxitin, cefuroxime, cefotetan
 •Third generation: cefotaxime, ceftriaxone, ceftazidime 
 •Fourth generation: cefepime, cefozopran, cefpirome, cefquinome