Antibacterial Spectrum

The cephalosporins are classified into generations (Table 45.2) according to their antibacterial spectrum and stability to p-lactamases. The first-generation cephalosporins have in vitro antimicrobial activity against streptococci, methicillin-sensitive S. aureus, and a few gram-negative bacilli. The second-generation cepha-losporins have greater stability against p-lactamase inac-tivation and possess a broader spectrum of activity to include gram-positive cocci, gram-negative organisms, and anaerobes. Among the second-generation cephalo-sporins, the cephamycins (cefoxitin [Mefoxin], cefotetan [Cefotan], and cefmetazole [Zefazone]) have the most activity against Bacteroides fragilis. The extended-spectrum, or third-generation, cephalosporins possess a high degree of in vitro potency and p-lactamase stability and a broader spectrum of action against many common gram-negative bacteria and anaerobes while retaining good activity against streptococci. Third-generation cephalosporins are less active against staphylococci than the earlier generations. The agents with the greatest activity against P. aeruginosa are cefepime, cefoperazone, and ceftazidime. Cefepime has been called a fourth-generation cephalosporin because of its great in vitro activity against several gram-positive and gram-negative organisms. The distinction between third and fourth

Was this article helpful?

0 0
Nicotine Support Superstar

Nicotine Support Superstar

Stop Nicotine Addiction Is Not Easy, But You Can Do It. Discover How To Have The Best Chance Of Quitting Nicotine And Dramatically Improve Your Quality Of Your Life Today. Finally You Can Fully Equip Yourself With These Must know Blue Print To Stop Nicotine Addiction And Live An Exciting Life You Deserve!

Get My Free Ebook


Post a comment