ABSTRACT
Pristinamycin is a mixture of water-insoluble pristinamycin IA (PIA, 90–97%) and pristinamycin IIA (PIIA, 3–10%), derived from Streptomyces pristinaespiralis. The former is a group B streptogramin (a peptidic macrolactone or depsipeptide), whereas the latter is a group A streptogramin (a macrolide: polyunsaturated macrolactone). Structurally similar to pristinamycin, virginiamycin is derived from Streptomyces virginiae and is composed of virginiamycin S and virginiamycin M—respectively, a peptidic macrolactone and a macrolide. Group A and group B streptogramins are bacteriostatic by reversible binding of the 50S subunit of 70S bacterial ribosomes (Pechere, 1997). The molecular structure of the two pristinamycin components is shown in Figure 78.1. Chemical structure of pristinamycins. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315152110/08d8042d-9481-4a8d-8c27-9bd589f6de6b/content/fig78_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
