New cephalosporins

Abstract

The cephalosporins are broad-spectrum beta lactam antibiotics. They have been categorized as first, second, third and fourth generation agents based mainly on their spectrum of activity. First generation cephalosporins are most active against aerobic gram-positive cocci. Second generation cephalosporins are more active against selected gram-negative organism. Third generation cephalosporins are the most active against gramnegative organisms and fourth generation has the widest spectrum including Pseudomonas aeruginosa. The oral cephalosporins which include cefdinir, cefditoren pivoxil, cefixime, cefpodoxime proxetil and ceftibuten are used for oral therapy of mild to moderate respiratory infections such as otitis media, sinusitis and acute exacerbations of chronic bronchitis. However, methicillin resistant Staphylococcus aureus (MRSA) species are resistant to all the cephalosporins. Recently, fifth generation cephalosporins with enhanced activity against MRSA are under investigation in clinical trials. Among them, ceftobiprole has been approved in Canada and Switzerland, and ceftaroline in the US.