New antibiotics for infections caused by resistant organisms

A continued increase in the expression of resistance among bacterial pathog ens has prompted the development of a variety of new compounds directed aga inst resistant strains of bacteria. Recently, the most dramatic increase in resistance has been among gram-positive organisms, and the predominant are as of development have been within a few classes of agents. Expanded spectr um fluoroquinolones offer advantages against many resistant gram-positive o rganisms, including S. pneumoniae and S, aureus. Newly developed classes of antimicrobials offer some unique activity against resistant staphylococci and enterococci. The first classes approved for use in the US are the strep togramins, specifically quinupristin/dalfopristin (Synercid), and the oxazo lidinone linezolid (Zyvox). Other new classes of agents, including the keto lides, everninomycins, and newer glycopeptides, such as LY-333328, are in t he early stages of development.