Streptogramin B is a macrolide antibiotic.1 It inhibits the growth of Clostridium, Peptostreptococcus, and Propionibacterium bacterial species (MIC90s = 2, 0.5, and 8 μg/ml, respectively).2 Streptogramin B inhibits protein synthesis by interacting with the 50S ribosome.1 Resistance to streptogramin B is conferred by erythromycin ribosome methylation (erm) genes, which code for methylases that methylate the 50S ribosome, interfering with streptogramin B binding.
1.Roberts, M.C., Sutcliffe, J., Courvalin, P., et al.Nomenclature for macrolide and macrolide-lincosamide-streptogramin B resistance determinantsAntimicrob. Agents Chemother.43(12)2823-2830(1999) 2.Laforest, H., Fourgeaud, M., Richet, H., et al.Comparative in vitro activities of pristinamycin, its components, and other antimicrobial agents against anaerobic bacteriaAntimicrob. Agents Chemother.32(7)1094-1096(1988)