<unk>  (sometimes abbreviated<unk> N) refers to a group of beta-lactam antibiotics used in the treatment of bacterial infections caused by susceptible, usually Gram-positive, organisms. The name<unk> ” can also be used in reference to a specific member of the<unk>  group<unk> am Skeleton, which has the molecular formula R-C9H11N2O4S, where R is a variable side chain.
Penicillin
Carbenicillin
Quinolone
Anthracycline
Tetracycline 
Phenoxymethylpenicillin
Piperacillin
Methicillin