Streptogramin analogues

Abstract

Among the large number of antibiotics that inhibit protein synthesis in prokaryotic cells, the streptogramins are unique in that they consist of two kinds of structurally unrelated molecules (group A and group B) [1,2]. The synergy between the two types of molecule confers real advantages over other classes of antibiotics. Since their discovery, intensive efforts have been made to elucidate the mechanism of action of the streptogramins and to synthesise modified analogues of the two groups of constituents [3,4]. In spite of their effectiveness, these naturally occurring antibiotics have not been extensively used: their poor water solubility means that they cannot be applied to treat severe bacterial infections. This problem was solved by intensive work leading to the synthesis of water-soluble derivatives of the two groups. It was only recently that the first water-soluble, injectable semisynthetic streptogramin, RP 59500 (Rhône-Poulenc Rorer), was selected as a candidate for clinical trials [5,6]. The efficacy of this compound has revived interest in this family of antibiotics, which was first discovered thirty years ago. RP 59500 has excellent activity against Gram-positive bacteria and is currently in phase II clinical trials. Published data concerning its in vitro and in vivo antibacterial efficacy suggest that this new streptogramin can be useful for the treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and staphylococci, pneumococci, and Enterococcus faecium resistant to macrolides-lincosamides-streptogramin B (MLS_B).