Abstract
The resistance of Staphylococcus aureus MS-9610 to tylosin and 3-O-acetyltylosin was due to the decreased affinity of its ribosome system to these macrolides. However, 3-O-acetyl-4''-3-O-isovaleryltylosin was found to bind to ribosomes of the strain about three times more than 3-O-acetyltylosin. This binding was not interfered by tylosin and 3-O-acetyltylosin. The 4''-O-acyl group and the mycinose moiety were suggested to have an important role in the binding of tylosin derivatives to ribosomes of resistant strains.
