Which antibiotic is considered best for GNRs among the beta-lactams?

Cefepime is recognized as one of the most effective beta-lactam antibiotics for treating gram-negative rods (GNRs). This is largely due to its broad-spectrum activity against various GNRs, including some that are resistant to other antibiotics. Cefepime is a fourth-generation cephalosporin that not only covers a wide range of GNRs but also has enhanced stability against beta-lactamases, which are enzymes produced by some bacteria to resist the effects of beta-lactam antibiotics.

In particular, cefepime is effective against organisms such as Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, making it a preferred choice in serious infections where these pathogens are suspected. Its pharmacokinetic properties allow for good tissue penetration, and it is typically well-tolerated by patients.

Other beta-lactam antibiotics mentioned, like ampicillin, penicillin, and ticarcillin, have a narrower spectrum and are less effective against many of the resistant strains often encountered in clinical practice. For example, while ampicillin can be used against certain GNRs, it is less effective against Pseudomonas and other more resistant strains compared to cefep