Gram-positive/negative bacteria cephalosporins

First-generation cephalosporins, introduced into human medicine in the 1960 s and 1970 s, are basically similar in antibacterial activity and differ mainly in their pharmacokinetic properties. These include all of the currently available orally active cephalosporins, and are relatively susceptible to beta-lactamase, active against most Gram-positive bacteria and have a limited spectrum of activity against the Gram-negative organisms. 

P-Lactam group of antibiotics. More effective against Gram-positive than Gramnegative bacteria but some cephalosporins, such as ceftazidime, are very effective against Gram-negative bacteria. 

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