[Kasugamycin methylase modified by ribosomal RNA from group A streptococci]

Kasugamycin sensitivity in Escherichia coli depends on the specific enzyme methylating rRNA. Native group A streptococci (GAS) were found to be sensitive to kasugamycin. After introduction of the erythromycin gene located on the transposon Tn916E into GAS some of the strains obtained kasugamycin resistance together with erythromycin resistance (erm). One of these strains carrying the transposon in its chromosome was tested for methylase activity. It was demonstrated to be deficient in kasugamycin methylase (ksg). The presented data proves the presence of ksg methylase in GAS. Evolutionary relationship between erm and ksg genes is discussed.